NOTIZIARIO Neutroni e Luce di Sincrotrone - Issue 10 n.1, 2005

NOTIZIARIONeutroni e Luce di SincrotroneVol. 10 n. 1 2005

EDITORIALC. Andreani

SCIENTIFIC REVIEWSInvestigating large scale structures by combiningsmall angle and ultra small angle neutron scatteringF. Lo Celso, I. Ruffo, A. Riso and V. Benfante

Star-Like polymer solutions studies by light andneutron scatteringG. Di Marco, N. Micali, R. Ponterio, V. Villari and A. Hainemann

Inelastic ultraviolet scattering beamline at ElettraC. Masciovecchio, A. Gessini, S. Di Fonzo and S.C. Santucci

µ &N& SR NEWS

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Cover photo:Conformation of the pPEGMA graft-polymer, that, in a selective solvent,mimes a star-polymer. Differently fromstar polymers, however, its interactionpotential is described by an adhesivehard-sphere model.

Il è pubblicato a

cura del C.N.R. in collaborazionecon la Facoltà di Scienze M.F.N. e ilDipartimento di Fisica dell’Universitàdegli Studi di Roma “Tor Vergata”.

Vol. 10 n. 1 Gennaio 2005Autorizzazione del Tribunale diRoma n. 124/96 del 22-03-96

DIRETTORE RESPONSABILE:

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HANNO COLLABORATO

A QUESTO NUMERO:

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om graficavia Fabrizio Luscino 7300174 RomaFinito di stamparenel mese di Gennaio 2005

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Vol. 10 n. 1 January 2005


S U M M A R Y


EDITORIAL .................................................................................................................................................. 2C. Andreani

SCIENTIFIC REVIEWS

Investigating large scale structures bycombining small angle and ultra small angleneutron scattering ....................................................................................................... 3F. Lo Celso, I. Ruffo, A. Riso and V. Benfante

Star-Like polymer solutions studies by light and neutron scattering........................................................................... 8G. Di Marco, N. Micali, R. Ponterio, V. Villari, A. Hainemann

Inelastic ultraviolet scattering beamline at Elettra ....... 13C. Masciovecchio, A. Gessini, S. Di Fonzo and S.C. Santucci

BRISP - A New Thermal Neutron BrillouinScattering Spectrometer at the InstitutLaue-Langevin ............................................................................................................. 20D. Aisa, E. Babucci, F. Barocchi, A. Cunsolo, F. D’Anca,A. De Francesco, F. Formisano, T. Gahl, E. Guarini, S. Jahn,A. Laloni, H. Mutka, W.-C. Pilgrim, A. Orecchini, C. Petrillo,F. Sacchetti, J.-B. Suck, G. Venturi

µ & N & SR NEWS ........................................................................................................................... 32

MEETING REPORTS........................................................................................................................... 37

CALENDAR .............................................................................................................................................. 42

CALL FOR PROPOSAL ................................................................................................................. 43

FACILITIES ............................................................................................................................................... 44



EDITORIAL

2

NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE • Vol. 10 n. 1 January 2005

Developments occurred at synchrotron ra-

diation and neutron facilities during 2004

have been impressive. The construction of

Diamond, the new synchrotron, is pro-

gressing as scheduled, in South Oxfordshire on the

Chilton/ Harwell science campus. The ‘super micro-

scope’ is housed in a striking doughnut-shaped

building over half a kilometre in circumference, cov-

ering the size of 5 football pitches, with first users ex-

pected at the new X ray source in early in 2007. This

will occur shortly before first neutrons on the Second

Target Station, which is also making great progress.

With a choice of first day instruments suite at the cut-

ting edge of technology, and that can adapt to meet

the changing needs of our research communities.

Both initiatives are destined to transform the RAL site

in a major centre for condensed matter science, open-

ing up new opportunities in bio-molecular science,

nanoscale science, advanced materials and soft con-

densed matter.

The other two important projects in progress are J-

PARC and SNS. They are quite impressive too. The

JAERI-KEK, the Joint Facility for High Intensity Pro-

ton Accelerators in Japan, is the new and exciting ac-

celerator project aiming to produce MW-class high

power proton beams at both 3 GeV and 50 GeV. Con-

struction of J-PARC started in 2001 and the anticipat-

ed first beam is planned for in the summer of 2007.

The SNS source construction continues at Oak Ridge,

Tennessee and the Central Laboratory and Office

(CLO) Building is now completed, complete occupan-

cy of the SNS staff officially occurred in fall 2004.

A last year event is the award of the FEL prize 2004

announced during the the Free-Electron Laser (FEL)

conference, the annual event where the FEL commu-

nity gathers to discuss progress and new ideas in the

field. The 2004 edition was hosted by the Sincrotrone

Trieste and took place in the “Stazione Marittima” at

the waterfront in the centre of Trieste. The prize was

awarded to Vladimir Litvinenko from BNL and Hi-

royuki Hama from Tohoku University in Japan, for

their fundamental and pioneering contributions in the

development of Storage Ring Free Electron Lasers.

The scientific reports of this issue summarize recent

investigations of rocks and marbles, by the combina-

tion use of SANS and USANS techniques, and of

polymer solutions by light and neutron scattering,

and recent highlights from the IUVS and BRISP

beamlines installed at ELETTRA and ILL, respective-

ly. All these studies confirm the increasing dynamism

of the neutron and synchrotron radiation community.

Carla Andreani

FOR INFORMATION ON:

Advertising for Europe and US, rates and insertsplease see:


Conference Announcements please contact:

Ms. Desy CatenaTel. +39 6 72594100Fax +39 6 2023507e-mail: [email protected]

SCIENTIFIC REVIEWS

3

Vol. 10 n. 1 January 2005 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

AbstractSmall Angle Neutron Scattering (SANS) and Ultra SmallAngle Neutron Scattering (USANS) are used to investigate avariety of systems from rocks and marbles to biological sam-ples and block copolimer solutions. The importance of combin-ing the two techniques as well as the different models to fit thecombined experimental data are here highlighted.

IntroductionInvestigation of large scale structures requires experi-ments involving small values of the momentum transferq (q = 4πsinθ/λ, with 2θ the scattering angle and λ thewavelength of the scattered neutrons). Conventionallythe small q neutron scattering technique is divided intotwo regions: the Small Angle Neutron Scattering (SANS)region corresponding to Q > 0.001 Å-1, and the UltraSmall Angle Neutron Scattering (USANS) region corre-sponding to Q< 0.001 Å-1. By combining the two tech-niques, today is possible to investigate structures withdimensions varying from nanometers all the way to sev-eral ten microns. Many natural and industrial materialsare characterized by structures in the same range of di-mensions. So combined SANS-USANS experiments arebound to become more and more common. Only recent-ly, following the AWT [1,2] tail reduction method, US-ANS has developed into a powerful standard methodfor the investigation of large scale structures. Today US-ANS instruments reach a peak to noise ratio better than105 coupled with a Q range from 10-5 to 10-2 Å-1, allowingfull overlap with many SANS instruments. In additionmeasuring time of less than 30’ allows slow kinetics tobe followed with time resolved USANS experiments. Inthis article we shall present a few cases ranging fromnatural materials (rocks, biogenic platforms, bones) toman made materials (block copolymers). We shall pre-sent some isothermal and also variable temperatureTime Resolved Ultra Small Angle Neutron Scattering(TR-USANS) data which give the possibility to test theunimer-aggregate transition of an aqueous solution of atri-block copolymer in a wide range of thermodynamic

conditions. By combining SANS and USANS experi-ments scattering data covering five orders of magnitudein momentum transfer can be carried out. This is partic-ularly important to gain information about fractal aggre-gation and in general, to distinguish between surfaceand mass fractals.

ExperimentalUSANS and SANS measurements were performed at theKWSIII and KWSII instrument of the neutron scatteringfacility FRJ-2 of the Forschungszentrum Jülich (Ger-many) [3], which covers the range 1.6x10-5<q<1.4x10-3Å-1

(λ =12.7Å) for the USANS and 10-3<q<0.2 Å-1 (λ =7Å) forthe SANS. Experimental data were collected also at theHFIR USANS facility of the Oak Ridge National Labora-tory (USA) which is a Bonse-Hart double-crystal diffrac-tometer equipped with triple-bounce Si(111) channel-cutcrystals, which have been modified by cutting an addi-tional groove for a cadmium adsorber [1] and by verydeep surface etching . Data obtained in three sectionscharacterized by different theta-steps and accumulationtimes, have been desmeared, normalized by the primaryincident neutron beam fluctuations, intensity variationsdue to monochromator positioning, sample thicknessand sample transmission and then spliced to the highangle portion by means of standard techniques. USANSexperiments were also performed at the neutron opticalbench instrument S18 installed at the 58 MW high fluxreactor at the Institut Laue-Langevin (Grenoble, France)[4]. In the double crystal spectrometer configuration,triple bounce channel cut perfect Silicon crystals areused as monochromator and analyzer, covering therange 2x10

-5< q <5x10

-2Å

-1. SANS measurements on the

LOQ spectrometer of the Rutherford Appleton Laborato-ry (Chilton, UK) were performed with a fixed sample-to-detector distance of 4.3 m and variable wavelength (2.2-10.0 Å, determined by time-of-flight), providing an effec-tive q-range 0.01-0.22 Å-1 in a single measurement. Theintensity of neutrons was recorded on a position-sensi-tive 64 x 64 pixel 2-D detector.

INVESTIGATING LARGE SCALE STRUCTURESBY COMBINING SMALL ANGLE AND ULTRA SMALLANGLE NEUTRON SCATTERING

Fabrizio Lo Celsoa*, Irene Ruffob , Angelo Riso and Valerio Benfante a

aDipartimento di Chimica Fisica “F. Accascina”Università degli Studi di Palermoviale delle Scienze, 90128 Palermo (Italy)

bIstituto Superiore “U. Mursia”, Carini (Italy)*corresponding author email: [email protected]: (+39) 091 590015, phone: (+39) 091 6459841

Paper received June 2004

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ResultsFigure 1 shows USANS experimental data for a sampleof rock called norite (coming from South Africa), whichis granular crystalline rock consisting essentially of a tri-clinic feldspar (as labradorite) and hypersthene . Best fitto the experimental data were obtained by using the ex-pression for a mass fractal as highlighted in eq. 1 [5]

I(q) = q–1Γ(β)Lβcut [1+(qLcut)

2]–β/2 sin[β arctan(qLcut)] (1)

with β = Dm – 1.

In this case the experimental data, considering the fractalbehaviour, span more than two decades in momentumtransfer and more than four decades in intensity (refer-ring to the single power law) with fractal dimensionDm=2.1 and upper cut-off length Lcut = 62000 Å.A different behavior is observed when different kind of“rocks” are taken into account. In particular we will con-sider a marble sample and its strictly related parent, a

sample of limestone. Marbles can be considered as theresult of the isochemical metamorphic evolution, in dif-ferent conditions, of a parent rock (protolith): normally asedimentary carbonate with a highly variable calcitic-dolomitic composition, or a previous marble. This in-volves the destruction of the originating minerals (most-ly calcite-dolomite) and their recycling through a furthercrystallization process. Figure 2 shows the scatteringcross section (open circles), obtained by means of US-ANS experiment, of such protolith, a sample of lime-stone. Lines are best fit of the data to a hierarchical struc-

ture model which takes into account the existence of anetwork of fractal aggregates of size R formed bymonodispersed solid primary particles of radius r [6].The scattering intensity as a function of the scatteringvariable q reads:

I(q) µ P(q, r, Ds) S(q, r, D, R) (2)

where

and

P(q, r, Ds) being the form factor referring to the singleprimary particle and S(q, r, D, R) the structure factor thatreflects the degree of order of primary particles along theaggregates.Ds is related to the dimensionality of the interfacial re-gion of the primary particles, and its value must be be-tween 2 and 3 (Ds = 2 is for smooth particles followingthe Porod law I µ q-4).D is the power law exponent of the fractal aggregates.

( )[ ])qRarctan(1DsinqR

11

qr)1D(D

1)R,D,r,q(S2D1

2D−⎟⎟

⎠

⎞⎜⎜⎝

⎛+

−Γ+=

−

2

6Ds

22rq32

1Ds)r,P(q,

−

⎟⎟⎠

⎞⎜⎜⎝

⎛+=

Figure 1. USANS data for a sample of norite (South Africa). Solid linesrepresents best fit to the eq. 1.

Figure 2. USANS data for a sample of grey limestone. Solid lines repre-sents best fit to the eq. 2.

Figure 3. USANS and SANS data for a sample of white italian marble(Carrara). Solid lines represents best fit to the eq. 2.

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Figure 3 shows the combined USANS-SANS experimen-tal data for a white italian marble (Carrara); best fit wereobtained according to eq. 2, applying the same modelused for the limestone. Accordingly to the marble forma-tion process, previously highlighted, the parameter val-ues obtained from the fit procedure show the dimensionof the primary particles increases going from the pro-tolith (limestone, r = 800 Å, Ds = 2.9) to a marble of medi-um metamorphic degree (Carrara, r = 4600 Å, Ds = 2).The thin section photograph (thickness of about 20 µm)observed in transmitted polarized light is reported infigure 4; it shows the macroscopic structure of the Car-

rara sample which is characterized by a homogeneouslygranoblastic fabric (i.e. homeoblastic) with very regularcrystal boundaries, giving an overall polygonal to mosa-ic configuration (average grain size 0.35 mm). This isdue to metamorphic equilibrium reached over very longtime at the metamorphic temperature (300-400° C) [7]. USANS-SANS combined measurements were carriedout to reveal fractal patterns in biogenic platforms, inparticular the case of reefs built by Dendropoma petraeum.A typical feature of many tropical and temperate rockyshores is the development of biogenic platforms at tidelevel resulting from a massive overgrowth of the cylin-drical shells of vermetid gastropods. In the Mediter-ranean area, the vermetid gastropod Dendropoma pe-traeum is the dominant reef building species along thelower midlittoral fringe. Preliminary observations onmacroscopic samples suggested that vermetid growthfollows a fractal pattern (figure 5a). SANS and USANSmeasurements have been performed on a series of sam-ples coming from different locations along the shorelinenear Palermo (Sicily, Italy). Preliminary investigation bymeans of X rays diffraction and scanning electron mi-

croscopy (SEM) have shown that vermetid shells aremainly constituted by calcium carbonate in the form ofaragonite. SEM pictures clearly show both the structuralunits of the vermetid shells and, at progressive magnifi-cation, aragonite crystals (figure 5b,c and d). Experimen-tal data concerning both solid sample and powders haveshown a power law dependence, typical of fractal be-haviour. Samples are probably constituted by fractal ag-gregates at different length scales or, in other words, anetwork of fractal clusters formed by solid primary par-ticles with a rough surface. Experiments have been alsoperformed doing contrast matching of the solid matrix

(calcium carbonate) with a mixture of D2O and H2O inorder to obtain structural information on the interfacialstructure of wet sample. If a pore network is totally filledby the solvent and the contrast matching condition isreached, then the scattering from this system would benegligible but when the solvent partially fills a pore net-work then scattering from the part of the network filledby the liquid is negligible and only the scattering fromthe porosity that is effectively closed to the liquid will bemeasured. One contrast matching condition has beenmeasured and a network of fractal clusters has been ob-served. In figure 6 it is reported the combined USANS-SANS pattern in the best contrast match condition(D2O/H2O 70% w/w). Best fit were obtained by consid-ering the system characterized by two length scales Lmax

and Lmin. Above Lmax (about 1600 Å) the system is char-acterized by a surface fractal structure and experimen-tal data have been fitted using eq. 3 [8,9] with a outercut-off length of 5000 Å and Ds = 2.7. At shorther lengththe system shows a power law I µ q-α) with α < 3 char-acteristic of a pore (or mass) fractal and therefore eq. 4can be used.

Figure 4. Thin section photograph showing the macrostructural charac-teristics (i.e. fabric) of the Carrara marble sample (polarized light,crossed Nicols). Actual size is 3.5 x 2.6 mm.

Figure 5. a) Macroscopic detail of a section of the vermetid gastropodDendropoma petraeum shell. b), c) and d) SEM pictures of the latter sampleat different magnification.

I(q) = q–1Γ(β)Lβcut [1+(qLcut)

2]–β/2 sin[(Ds-1) arctan(qLcut)] (3)

where β = 5 – Ds .

I(q) = Ip [1+(qLmin/2)–Dp]e–q2L2min

/20 (4)

The latter equation can be used for a network as a conse-quence of the aggregation of spherical pores of diameterLmin and fractal dimension Dp (in this case Lmin = 88 Åand Dp = 2.48). The structure factor is represented by theterm in brackets while the form factor is represented bythe Guinier approximation for the scattering from asphere of diameter Lmin.

Figure 7 reports another example of neutron scatteringfrom a biological sample: a dinosaur bone tissue. Thecombined USANS-SANS experimental data were fittedusing a linear combination of equation 1 and 3. At lengthscales above 1300 Å the system exhibit a mass fractal

structure with fractal dimension Dm = 2.65 and outer cut-off limit of 20000 Å, while at shorter distances a surfacefractal structure can be seen (Lcut = 47.5 Å and Ds = 2.65)Finally, we present time and temperature resolved US-ANS experiments on a 25.3% w/v (indicated as B25) ofthe tri-block 25R5 reverse pluronicTM in D2O. In thecoblock each ethylene oxide (EO) segment are linked totwo propylene oxide (PO) moieties. The polymer 25R5corresponds to (PO)18-(EO)48-(PO)18 formulation. Previ-ous time-of-flight (TOF) SANS experiments performedon this solution indicated a dramatic change of the for-ward scattering, upon heating the solution betweenroom temperature and 60 °C. In particular, between 20

°C and 50 °C the system showed a gradual change in thedegree of order. Figure 8 shows some selected time re-solved scattering patterns of the tri-block recorded at 20°C, immediately after preparing the solution. The acqui-sition time of each frame was 20 min. The increase of

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Figure 6. USANS and SANS data for a sample of dinosaur bone tissue.Solid lines represents best fit to the eqs. 1 and 3.

Figure 7. USANS and SANS data for a sample of vermetid gastropodDendropoma petraeum shell. Solid lines represents best fit to the eqs. 3and 4.

Figure 8. Time resolved scattering patterns of the tri-block PPO-PEO-PPO solution B25. The patterns were recorded within time frames of 20minutes. Only selected patterns are shown in this graph. It can be seenclearly, that forward scattering increases with time.

Figure 9. Temperature dependant scattering patterns of the tri-blockPPO-PEO-PPO solution B25. Forward scattering (I0) increases up to 32°C.From 33°C to 45°C I0 decreases dramatically to jump at 50°C into a DAB-like scattering behaviour with p=6.

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the scattering intensity with time indicates that the sys-tems gets increasingly ordered with time and that clus-ters in the micrometer range are eventually formed. Af-ter approximately 3 hrs the structural changes of thesystem decline. At this point, a series of isothermal scat-tering experiments have been performed. Scatteringframes of 20 min were recorded for a series of tempera-tures in the range 31-50 °C (figure 9). Since beginningthe scattering patterns show an increase of forward scat-tering as a consequence of the formation of clusters.From 33°C to 45 °C, the forward scattering decreasesmore than one order of magnitude, indicating increaseddisassembling of the clusters. In this temperature range

the scattering cross section can be described by a powerlaw with the exponent α = 3.3. The last measurementwas taken at the temperature of 50°C, where a suddenjump of the scattering intensity could be recorded andthe solution became turbid. The scattering behaviourcan be described by the two phase Debye–Anderson–Brumberger model (DAB) [10], with the exponent p = 6as expressed in eq. 5.

(5)

where a is the correlation length, ∆ρ is the scatteringlength density difference (contrast) and φ1 and φ2 repre-sent the volume fractions of the two phases. The time re-solved USANS series were taken in time frames of 30min covering the q-range from 2x10-5 to 2x10-3 Å-1.A clearer picture of the change in structure just describedcan be seen in figure 10 where we have reported USANSand SANS data at three temperatures, representative ofdifferent structure regimes.

ConclusionsApplication of the combined USANS SANS techniqueson a variety of systems has been here presented. Model-ing of the experimental data, by means of the differentscattering equations, have permitted to derive structuralparameters and better understanding of the various sys-tems up to length scales that, in some cases, overlap withthe traditional microscopy techniques.

Acknowledgements We wish to thank the many colleagues and friends whohelped us with the experiments reported here, particu-larly G.D. Wignall and J. S. Lin (ORNL, Oak Ridge,USA), R. K. Heenan (RAL, Chilton, UK), M. Baron (ILL,France), E. Uccello, S. Rotolo, I. Donato, S. Riggio and T.Dieli (University of Palermo). Financial support fromCNR, European Community (for the program “JülichNeutrons for Europe” under the 6th EU Framework Pro-gramme) and INFM is gratefully acknowledged.

References1. M. M.Agamalian, G. D. Wignall, and R. Triolo, J. Appl. Cryst., 30, 345-

349, (1997).2. M.M. Agamalian, A.R. Drews, J.G. Barker, C.J. Glinka, Physica B, Vol.

241-243, 189-191, (1998).3. www.fz-juelich.de/iff/wns_kws3, www.fz-juelich.de/iff/wns_kws24. M. Hainbuchner, M. Villa, G. Kroupa, G. Bruckner, M. Baron, H.

Amenitsch, E. Seidl, and H. Rauch, J. Appl. Crystallogr., 33, 851-854,(2000).

5. D.W. Schaefer and K.D. Keefer, Phys. Rev. Lett., 53, 1383-1386 (1984).6. A. Emmerling, R. Petricevic, P. Wang, H. Scheller, A.Beck and J.

Fricke, J. Non-Cryst. Sol., 185, 240-248 (1994).7. C. Gorgoni, L. Lazzarini, P. Pallante and B. Turi, An updated and de-

tailed reference database for the main Mediterranean marbles used inantiquity, Interdisciplinary studies on ancient stone, J. J. Herrmann,N. Herz and R. Newman eds, 115–131, Archetype, London (2002).

8. D.F.R Mildner. and P.L. Hall, J. Phys. D, 19, 1535-1545 (1986).

p22

221

3

aq1

1)(a8)q(I

+ρ∆φφπ=

Figure 10. Temperature dependant USANS and SANS combined pat-terns of the tri-block PPO-PEO-PPO solution B25

IntroductionLinear, branched and hyper-branched polymers havedifferent and unique mechanical, rheological and solu-tion properties that depend on the chain structure andon both the type and degree of branching.[1,2] Such awide tuning of the macroscopic behaviour starting frommodifying branching junctures had attracted a great dealof interest not only for the application in the industrialand biomedical fields,[3-5] but also for an academicpoint of view.[6-8] The main goal in the study of poly-mers consists in finding a direct correlation betweenmacromolecular chain structure and its macroscopicproperties and in describing the system by using an ef-

fective interaction between chains. Once this goal isreached the structure and thermodynamics of polymersolutions, as phase transitions, can be predicted.A special class of branched polymers is constituted bythe star-polymers whose physical properties, dependingon the number of arms grafted to the central core, canchange from those of polymers to those of colloid-likesystems. A great deal of interest, moreover, has been devoted tothe formation of various structures constituted by poly-mer chains containing both hydrophobic and hydrophilicsegments. Graft copolymers with side chains which arechemically different from the backbone take a great rele-vance, because their properties can be modulated by thecombination of selective interactions with solvents. Thisoccurrence implies a high engineering potential. [9]The results presented here report on a study of the

structural properties of the polymer of poly(ethyleneglycol) ethyl ether methacrylate (so-called pPEGMA[10]) in solution by Neutron Scattering, which shows,together with results previously obtained by some of usby Light Scattering[11], that in particular solvents, thesingle polymer entity can take a star-like conformation,in which the methacrylate backbone is confined in theinner part (where solvent does not penetrate) by thePEO side chains.

Structure of pPEGMApPEGMA is a graft polymer composed by oligomericPEO units grafted to inert methacrylate chains (Fig.1).

PEGMA, was already successfully used as polymericmatrix for the fabrication of electrochromic devices;[12-14] it joins the properties of both components: thePEO units assist the ionic diffusion when coupled withthe salts and the inert metacrylate chains is useful in mi-nimizing the crystallinity of the overall system. It repre-sents one of the most reliable candidates in many appli-cations, but, notwithstanding the large technological use,some structural mechanisms are not fully understood atthe moment. The characterization of this polymer in so-lution would allow for a better understanding of its in-ner structure in the amorphous state and, then, for im-proving its efficiency.pPEGMA solutions have been prepared at different con-centration in deuterated ethanol in a concentration ran-ge from 10-3 to 0.082 g/cm3 at a constant temperaturevalue of 25°C.

STAR-LIKE POLYMER SOLUTIONS STUDIED BY LIGHT AND NEUTRON SCATTERING

G. Di Marcoa, N. Micali a, R. Ponterio a, V. Villari a, A. Heinemann b

a) CNR - Istituto per i Processi Chimico-Fisici del CNRSez. Messina, Via La Farina 237, I-98123, Messina, Italy

b) Hahn-Meitner-Institut, BENSC, Glienicker Strasse 100,D-14 109, Berlin, Germany

Paper received June 2004

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Fig. 1. Monomer structure.

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Summary of Light Scattering resultsThe most general formula indicating the absolute scatte-red intensity from a system, under the assumption of asolution of monodisperse and centrosymmetric particlesand under the hypothesis of independence of intermole-cular and intramolecular averages, is:

I(Q) ∝ P(Q)S(Q) (1)

P(Q) and S(Q) being the normalized form factor and thestructure factor respectively.In a Light Scattering experiment equation (1) indicatesthe absolute excess scattered intensity from an isotropicsystem constituted by monodisperse particles, when il-luminated with a monochromatic linearly polarized li-ght:[15]

I(Q)=HMWcP(Q)S(Q) (2)

where c is the concentration in g/cm3, MW the molecularweight and H the optical constant equal to [16]:

.

In the latter n is the refractive index of the solvent, λ0 thewavelength of light in vacuum and NA the Avogadro’snumber.As reported in reference [11], for the static and dynamicproperties of pPEGMA/ethanol solutions we used a ho-me made computer controlled goniometric apparatuswith a duplicate Nd:YAG (532nm) laser linearly polari-zed orthogonally to the scattering plane. In the whole in-

vestigated concentration range the scattered intensitydid not depend on Q, indicating that particles are toosmall to be “seen” by Light Scattering; therefore, it wasbe set P(Q)=1. For the interpretation of the absolute scat-tered intensity in the whole range of concentration (seeFig.2) a model for the concentration dependence of S(Q)is required. The Elastic Light Scattering experiment in-volves low Q values so that we used exact solutions formodels implying S(0).After having used the simple hard sphere solution ofthe Ornestein Zernike equation[17] for S(0) ([S(0)]–1 =1+8φ, φ being the volume fraction) and checked the ef-fect of a repulsive potential to be added to the hardsphere model, through a positive quadratic term in φ tothe osmotic pressure,[18,19] without finding a fit resultgood enough, we took into account intermolecular at-tractive interactions together with the excluded volumeinteractions adopting the Baxter’s adhesive hard spheremodel[20-22]. It describes the potential U(r) for a sphereof radius R as:

(3)

where R-R’ is the thickness of the adhesive layer, Ω theadhesive potential and kBT the thermal energy. The analytical solution of the Ornstein-Zernike equationwas found by Baxter in the Percus-Yevik approxima-tion,[23] in the limit (called “sticking sphere” model)that the thickness approaches to zero but the stickinessparameter 1/τ=12exp [(R-R’)/R], remained finite. It is:

⎪⎩

⎪⎨

⎧

>

<<Ω−

<<∞

=

Rrfor 0

RrR'for

R'r0for )(

TBk

rU2

40

224⎟⎠

⎞⎜⎝

⎛dc

dn

AN

n

λ

π

Fig. 2. Absolute scattered intensity as a function of concentration. Blackpoints refer to Static Light Scattering data (left Y-axis) and yellow pointsrefer to Small Angle Neutron Scattering (right Y-axis). Both data sets aretaken at low Q. Continuous line is the fit of the Static Light Scattering(SLS) data according to the Baxter’s potential.

Fig. 3. Diffusion coefficient as a function of concentration. The verticaldashed lines indicate the crossover region.

(4)

Fig.2 shows the fit according to the Baxter’s model fromwhich, considering also equation (2), 1/τ=0.7±0.2,MW=45000 ± 2000 and c/φ=0.18 ± 0.01 g/cm3. The corre-sponding sphere radius was R≈5nm. The value of theoverlap concentration, which defines the crossover to thesemidilute regime, was obtained by the diffusion coeffi-cient behaviour (dashed region in Fig. 3).In the low concentration region the behaviour of D is de-scribed by the relation:[24-26] D=D0(1+kDc), being D0 thediffusion coefficient at infinite dilution and kD the dyna-mic virial coefficient. From D0, through the Einstein-Stokes relation [24]

(η being the solvent viscosity), the hydrodynamic radiusof the polymer is obtained: it is RH=8.5 ± 0.5 nm. Increa-sing concentration above the dilute regime a crossover is

observed indicating the beginning of the semidilute re-gion in which the linear behaviour is not fulfilled anddata obey a power law with an exponent equal to 0.7, inagreement with that predicted by de Gennes[27,28].Thiscrossover concentration represents the value at whichspheres of radius RH come into contact.The physical origin of the attractive interaction can be

understood by looking at Fig.4, in which the representa-tion of the more plausible pPEGMA conformation is re-ported. It looks to have a more compact solvent impene-trable zone in the inner part, where the methacrylatebackbone is confined by the grafted swollen (short) PEOchains, so miming a sort of star-polymer. Viewing pPEGMA as a star-like polymer, from the mea-sured molecular weight the average number of PEOarms was estimated to be close to 135. Therefore, attrac-tive intermolecular interactions can be attributed bothto the depletion of the solvent because of the interpene-tration of the arms and to the interaction between PEOarms. In fact, ethanol is a worse solvent than water forPEO, and polymer-polymer interaction can becomecompetitive with the polymer-solvent interaction con-tribution.

Neutron Scattering experimentOnce the system was characterized by Light Scatteringand a conformation hypothesized, Small Angle NeutronScattering (SANS) measurements are extremely useful ingiving information on polymer size and in indicating ifconformation is maintained also in the semidilute regionbeyond the overlap concentration. The neutron scattering experiment was carried out us-

ing the SANS instrument V4 at the BENSC Facility of

the Hahn-Meitner-Institute in Berlin. The two dimen-sional scattering contours were corrected for detector ef-ficiency, instrumental background and transmission andconverted (the program BerSANS was used) to scatter-ing cross sections per unit volume using water for cali-bration. The resolution of the instrument in this configu-ration, λ/λ=0.1, was also taken into account in the dataanalysis.

D

TkR B

H πη6=

23

6

12

903

19218)

28(11)]0([ φ

τ

τττφ

τ

−−++−+=−S

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Fig.5 Scattering cross section at different concentration values:c=0.00095 g/cm3, c=0.002 g/cm3, c=0.0039 g/cm3; c=0.0059 g/

cm3, c=0.008 g/cm3, c=0.016 g/cm3, c=0.032 g/cm3, c=0.082 g/cm3.

Fig. 4. pPEGMA conformation for a number of arms equal to 48 perfor-med using the ChemOffice energy minimization (MM2).

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In a Small Angle Neutron Scattering experiment equa-tion (1) becomes:

I(Q)=N[Σibi -ρ0υpol]2P(Q)S(Q) (5)

where N is the polymer number density, bi the atomscattering lengths, ρ0 the scattering density of the solventand υpol the volume occupied by the polymer.SANS spectra of pPEGMA/deuterated Ethanol areshown in Fig.5. Because at high Q values the coherentSANS cross section is superimposed to the incoherentbackground due to the hydrogen atoms of the polymerchains, the flat background at higher Q for different con-centration has been subtracted before starting with thedata analysis.As it can be seen, the Structure Factor contribution be-comes more and more evident increasing concentrationabove c=2.2x10-3 g/cm3. In fact, from an inspection ofFig.2, the intensity at low Q from SANS displays thesame behaviour obtained by Light Scattering,[11] indi-cating that interactions are present at relatively low con-centration values. At the lowest concentration the interference effects canbe considered negligible, so that the cross section of this

sample represents the “effective” form factor of the poly-mer. Up to Q=1 nm-1 the plot of the inverse normalizedcoherent cross section as a function of Q2 is linear (Fig.6),indicating that chains are not fully contrasted, but rathertheir distribution density decreases as described by theOrnstein-Zernike law:[17]

(6)

where ξ is the correlation length of the density distribu-tion. It results ξ =5 nm.Using the Kratky plot (Fig.7) is useful in describing theoverall shape of the polymer chain molecule: in essence,the Kratky plot shows a clear peak for a compact confor-mation, but has a plateau shape and then increases mo-notonically for a flexible chainlike molecule. The peakpresent at all concentration values indicates that chainstake a globular conformation and maintain it, at least upto c=0.082 g/cm3. From the peak position the radius ofgyration can be determined by the Benoit form factor forstar-polymers: [29]

(7)

where and f is the functionality, that, inour case, is equal to the polymerization degree of thechain, namely 135, as evaluated by Light Scattering.[11]Although this method is strictly valid only for the θ statethe obtained value of the radius of gyration is compati-ble with the correlation length.

ConclusionsNeutron Scattering measurements give clear informationfor completing the characterization of the polymerpPEGMA. In particular: - Chains take a globular shape with a more compact core

constituted by the solvent phobic methacrylate part anda less compact shell around constituted by the more sol-uble PEO arms. The pattern related to the diffractionfrom the particle, in fact, indicates a non-homogeneousobject whose correlation length is equal to 5 nm.

gQRf

fv

23 −=

P Qfv

v vf

v( ) exp exp= − − − +−

− −[ ] ( )[ ] ( )[ ]⎧⎨⎩

⎫⎬⎭

24

21

2 1

21

22

221

)0()(

ξQ

IQI

+=

Fig. 6. Inverse scattering cross section normalized by concentration forthe most dilute solution. The continuous line is the fit according to rela-tion (6).

Fig. 7. Kratky plot at c=0.008, as an example.

- This star-like conformation could be responsible for theattractive part in the interparticle potential because theinterpenetration of PEO arms can deplete the solventor because of the fact that the quality of the solventmakes polymer-polymer and polymer-solvent interac-tion competitive.

- SANS data indicated that, at least up to 0.082 g/cm3,chains maintain their globular conformation withoutgiving rise to any gel-network structures.

Further investigation are in progress in order to under-stand how the interaction with different solvents can af-fect the conformation of the chains or favour aggrega-tion processes.

References1. G.S. Grest, L.J. Fetters, J.S. Huang, and D. Richter, Adv. Chem. Phys.

XCIV, 67 (1996).2. J. Roovers, L. Zhou, P.M. Toporowski, M. van der Zwan, H. Iatrou,

and N. Hadjichristidis, Macromolecules 26, 4324 (1993).3. H. Xie, and P. Zhou, Adv. Chem. Ser. 211, 139 (1986).4. F.L. Baines, S. Dionisio, N.C. Billingham, and S.P. Armes, Macromole-

cules 29, 3096 (1996).5. B. Wesslen, M. Kober, C. Freij-Larsson, A. Ljungh, and M. Paulsson,

Biomaterials 15, 278 (1994).6. M. Watzlawek, C.N. Likos, and H. Lowen, Phys.Rev. Lett. 82, 5289

(1999).7. C.N. Likos, H. Lowen, M. Watzlawek, B. Abbas, O. Jucknischke, J. Al-

lgaier, and D. Richter, Phys. Rev. Lett 80, 4450 (1998).8. C. von Ferber, A. Jusufi, M. Watzlawek, C.N. Likos, and H. Lowen,

Phys. Rev. E 62, 6949 (2000).9. H.A.J. Battaerd, G.W. Treager, Graft Copolymers (Wiley-Interscience,

1967).

10. G. Di Marco, M. Lanza, A. Pennini, and F. Simone, Solid State Ionics127, 23 (2000).

11. N. Micali, V. Villari, Phys. Rev. E, 67, p. 41401 (2003).12. A. Pennisi, F. Simone, G. Barletta, G. Di Marco, M. Lanza, Electro-

chim. Acta, 44, 3237 (1999).13. G. Di Marco, M. Lanza , A. Pennisi, F. Simone, Solid State Ionics 127,

23 (2000).14. F.M. Gray, Polymer Electrolytes (Royal Soc. Chem., Cambridge, 1997).15. N. Micali, F. Mallamace, in Light Scattering. Plrinciples and Develop-

ments, ed. W. Brown, p.381 (1996).16. dn/dc=0.25 cm3/g and it is constant in the whole investigated con-

centration range.17. L.S. Ornstein, and F. Zernike, Proc. Acad. Sci. Amsterdam 17, 793 (1914).18. A.M. Cazabat, In Physics of Amphiphiles: Micelles, Vesicles and Microe-

mulsions, International school of physics Enrico Fermi, Course XC,edited by V. Degiorgio and M. Corti (North-Holland 1985), p.723.

19. A.A. Calje, W.G.M. Agterof, and A. Vrij, in \emphMicellization, So-lubilization and Microemulsion, vol. 2 (New York 1977).

20. R.J. Baxter, J. Chem. Phys. 49, 2770 (1968).21. L. Lobry, N. Micali, F. Mallamace, C. Liao, and S.H. Chen, Phys. Rev.

E 60, 7076 (1999).22. Y.C. Liu, S.H. Chen, and J.S. Huang, Phys. Rev. E 54, 1698 (1996).23. J.K. Percus, and G.J. Yevik, Phys. Rev. 110, 1 (1958).24. Berne, B.J.; Pecora, R. Dynamic Light Scattering with Application to

Chemistry, Biology and Physics, J. Wiley and Sons:New York, 1976.25. Cummins, H.Z. Photon Correlation and Light Beating Spectroscopy;

H.Z. Cummins and E.R. Pike, Eds.; Plenum Press: New York, 1974.26. Schaefer, D.W.; Han, C.C. Dynamic Light Scattering, ed. R. Pecora

Plenum: New York, 1985.27. P.G. de Gennes, Scaling Concepts in Polymer Physics (Cornell Univ.

Press, Ithaca, New York, 1979)28. M. Rubinstein , R.H. Colby, and A.V. Dobrynin, Phys. Rev. Lett. 73,

2776 (1994).29. L. Willner, O. Jucknischke, D. Richter, J. Roovers, L.-L. Lin, and N.

Hadjichristidis, Macromolecules, 27, 3821 (1994).

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AbstractThe recent construction of an Inelastic UltraViolet Scattering(IUVS) beamline at the ELETTRA Synchrotron Light Labora-tory opens new possibilities for studying the density fluctua-tion spectrum, S(Q,E), of disordered systems in the mesoscop-ic momentum (Q) and energy (E) transfer region not accessi-ble by other spectroscopic techniques. We will present firstIUVS results obtained on two prototype samples such as liq-uid water and vitreous silica. In water we were able to mea-sure the temperature dependence of the structural relaxationtime showing that the divergence in the transport propertiesdoes not need an underlying critical behaviour but can be ex-plained in the framework of the Mode Coupling Theory. Invitreous silica IUVS experiments gave clear experimental evi-dence of the presence of a step in the sound attenuation coeffi-cient at wavelengths between 6 and 60 nm thus locating acharacteristic length where sound waves interfere with glassinhomogenities.

IntroductionThe physics of systems without translational invariance,such as liquids, dense fluids and glasses, has been fasci-nating scientists for many years. The understanding ofliquid-to-glass transition mechanism, thermal anomaliesat low temperatures, divergence of transport propertiesand relaxation phenomena, is a challenge that deservesstrong experimental and theoretical efforts [1]. A largeamount of information about the physical properties ofthese systems can be deduced by the experimental deter-mination of the density-density correlation function,F(Q,t), or, equivalently, of its Fourier Transform, the dy-namic structure factor S(Q,E), in the largest momentum(Q) and energy (E) transfer region. S(Q,E) is directlymeasurable by experiments of inelastic scattering of ra-diation and neutrons [2,3].However, a single technique cannot completely cover, byitself, the entire range between interatomic distances andthe continuum scale. Visible Light (1.5 - 2.5 eV) Scatteringis a useful technique for studying a large class of materi-als, however it has the limitation that only very low mo-mentum transfers, not higher than ~ 0.03 nm-1, can bestudied due to the small momentum carried by the pho-

tons at the visible light wavelengths. Optical spectrome-ters and interferometers can, however, reach a very highenergy resolving power (namely E/∆E ~ 106-108). Re-cently, a UV laser source has been used to push the lightscattering technique up to ~ 0.07 nm-1 (HIRESUV facility- see Fig. 1).

On the other hand the inelastic scattering of thermalneutrons gives the possibility of studying the dynamicstructure factor S(Q,E) for momentum transfers muchlarger than those of light scattering. In fact, with theavailable techniques and instrumentation, it is possibleto investigate the region of momentum transfer between~ 3 nm-1 and ~ 2500 nm-1. However, due to the kinematicof the neutron-acoustic phonon scattering process, theaccessible exchanged energy region is limited. Actually,only disordered systems with sound velocity smallerthan 1.5 Km/s can be investigated with the existing in-struments. High-resolving power inelastic x-ray scattering (IXS)spectrometers have been constructed recently, and are

INELASTIC ULTRAVIOLET SCATTERING BEAMLINE AT ELETTRA

C. Masciovecchio1, S. Di Fonzo1, A. Gessini1, G. Ruocco2, S.C. Santucci3 and F. Sette4

1Sincrotrone Trieste, S.S. 14 km 163,5 in AREA Science Park34012 Basovizza, Trieste, ITALY2Dipartimento di Fisica and CRS-INFM SOFT, Università di

Roma “La Sapienza”, P.le A. Moro 2, 00185 Roma, ITALY3Università di Perugia, Dipartimento di Fisica, Via Pascoli 1,06100 Perugia, ITALY4European Synchrotron Radiation Facility, 6, Rue JulesHorowitz, BP 220, 38043 Grenoble, France

Paper received November 2004

Fig.1. Kinematic regions accessible from the existent instruments(DMDP2000, FP, IN5, ID16, ID28, HIRESUV). The two lines representtypical range of speed of sound measured in glass-forming systems andfluids.

now available for users at the ESRF in Grenoble (ID16and ID28). These facilities have an energy resolution of~1.5 meV and a range of momentum transfer between0.8 nm-1 and 25 nm-1. In this case there are basically nokinematic limitations on the exchanged energy, and IXShas been extensively used to study the collective dynam-ics of disordered systems [1]. The limitation at low Q, inthis case, lies in the limited energy resolution.Fig.1 shows, in a log-log plot, the regions in the (Q,E)space where the various instruments are now available,the lines of two typical velocities of sound are also dis-played. From the figure one can notice that in the rangeof exchanged momenta between 0.07 and 0.8 nm-1 thereis a kinematic region where collective dynamics cannotbe excited. However, this momentum transfer range is offundamental importance to gain insight into the struc-ture and dynamics of disordered systems. As a matter of fact, in contrast to the crystalline case, indisordered systems the understanding of the atomic dy-namics is complicated not only by the difficulties associ-ated with the absence of translational invariance, but al-

so by the presence of other degrees of freedom, such asdiffusion and relaxation in fluids, and hopping and tun-nelling processes in glasses. The presence of theseprocesses in disordered systems naturally introduces dif-ferent time-scales, τ, which are usually strongly depen-dent on the specific thermodynamic state. These time-scales affect the collective dynamical properties differ-ently, depending on its value with respect to the timescale tD, characterising the vibrational dynamics of the

particles around their quasi-equilibrium position. This isof the order of the inverse of the Debye frequency, whosevalue is comparable to that of a corresponding crystalwith similar density and sound velocity. Moreover onehas to consider that the topological disorder introduces asecond length scale ξ beside the interparticle distance a.The rich phenomenology observed in the dynamics ofdisordered systems is, therefore, often the consequenceof the interplay between these different structural (a andξ) and dynamic (τ, tD) scales.The collective dynamics in the absence of translationalinvariance can be easily treated theoretically in two lim-iting cases, namely excitations with characteristic spaceand time scales which are either very long or very shortcompared to the disorder scale ξ, and to the relaxationtime τ. The former corresponds to the hydrodynamiclimit, where the system is seen as a continuum, whereasthe latter corresponds to the single-particle kinetic limit,where the particle behaviour is described as a free mo-tion between successive collisions. In contrast, an ex-haustive theoretical understanding is still not available

in the intermediate region, defined by a length-scalecomparable to the correlation length of the topologicaldisorder and by a time scale comparable to tD. The possibility to investigate collective excitations in themesoscopic region could help in shedding light on sev-eral relevant questions on the dynamics of disorderedmaterials. Among them, we mention the following ones:i) Is the elastic continuum theory appropriate at meso-scopic length scale where the disorder of amorphous

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Fig. 2. An overview of thevacuum chamber containingthe 8 m focal length mono-chromator and analyser units.

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systems becomes relevant? ii) What is the origin ofsound attenuation in glasses? iii) With respect the Debyebehaviour of the corresponding crystal, what is the ori-gin of the excess in the specific heat and the excess in thevibrational density of states found in glasses? iv) Howdoes the structural relaxation affect the collective dy-namics in glass-forming systems? There are other points even more specific to this Q-re-gion that could be reminded. These are: i) The criticalscattering with highest intensities in the quasi-elastic re-gion near Q=0, ii) the study of the transition from purehydrodynamic to either generalised or kinetic behaviourin fluids, iii) the dynamics of all macro-molecular sys-tems which have the maximum of their structure factorin the low-Q region, like clusters, colloids, emulsionsand biological systems.The recent construction of an Inelastic Ultra-Violet Spec-trometer (IUVS) at the ELETTRA synchrotron laboratory[4] contributes to reduce the existing gap in momentumtransfer to less than the 0.3 - 0.8 nm-1 range. Moreover,we would like to mention another very interesting appli-cation of this instrument, which at present has got verylittle attention simply because of the lack of tunability ofthe incident photon energy in both laser and x-ray basedinstruments. This is the possibility to tune the incidentphoton energy to be resonant with an electronic excita-tion of the system. In this case the scattering cross sec-tion is expected to increase substantially, and, in samecase by various orders of magnitude. Moreover, in thehypothesis of a resonance broader than the typical col-lective excitations energy, which is a fraction of meV inthe considered cases, the resonant scattering will allowto study specific phenomena where the scattering signalis usually very low. Among them and of particular im-portance is the scattering from surface waves, whichgives information on the shear moduli and therefore onthe transverse dynamics of the system, a quantity thatcan be accessed experimentally only by indirect ways.The resonant Brillouin scattering would also open newpossibilities not yet exploited in the usual light scatter-ing experiments, as, for example, in the determination ofthe dynamics structure factors of specific species (in thepresence of different atomic and/or molecular speciesthe larger signal comes from the resonant one). Also, thecomparison of measurements made on- and off-reso-nance would give the possibility to determine a wholeset of partial dynamics structure factors. Finally, takingadvantage of the different tensorial properties of the res-onant and non-resonant cross sections, the resonant scat-tering technique could also be used to separate in thescattered intensity the rotational contributions fromthose arising from collision induced effects.In the next section we will describe into details the IUVSinstrument design. The following two sections are re-

porting on our recent investigations on water and vitre-ous silica, performed by IUVS at Q values around 0.1nm-1, a region of great interest, where peculiar dynami-cal behaviours are expected, as inferred by results ob-tained through the complementary Brillouin Light Scat-tering (BLS) and Inelastic X-ray Scattering (IXS) tech-niques [5 -8].

The instrumentIn order to perform IUVS spectroscopy three main re-quirements for the incident radiation had to be fulfilled:i) photon energy in the 5 - 11 eV range (λ ~ 240 – 110nm), ii) incident photon flux on the sample larger than1011 photons/s, iii) resolving power of the order of 105 to106, necessary to resolve the typical phonon-like excita-tions in the energy range of interest. Because of the high flux needed, the radiation source forthe IUVS beamline at ELETTRA has to provide at least1015 photons/s/0.1%bw. This calls for an undulator ofthe maximum length compatible with available length inthe straight sections of the storage ring (4.5 m). This re-quirement naturally implies a very high-emitted powerand power density, which can be harmful to the opticalelements of the beamline. For such a reason an exotic in-sertion device, the Figure-8 undulator [9], has been con-structed as an alternative to the standard vertical fielddevice. The main advantage of this solution is a much re-duced on-axis power density, which is obtained with nopenalty on the useful photon flux. Using a 32 mm periodfigure-8 undulator with maximum deflection parametersKx = 3.4 and Ky = 9.4, at the exit of a 600 ? 600 mrad2 pin-hole the total power of the synchrotron radiation is re-duced to about 20 W while the first harmonic delivers 2·1015 photons/s/0.1%BW. The beam coming from the source has to be cleaned fromthe high order undulator harmonics and, for this reason,three reflections have been used allowing also the trans-fer of the radiation into the monochromator stage. Morespecifically the beam impinges on a gold coated GLID-COP mirror internally water-cooled, which deviates thephotons in the vertical plane with an angle of 6o. A sec-ond externally water-cooled silicon mirror is used tobring back the beam parallel to the floor. The beam is then focused by a spherical silicon mirroronto the entrance slits of the monochromator with a de-magnification 20 : 1 and with an incident angle of 85o.Being the source size roughly 1 x 1 mm2, a spot of 50 x200 µm2 (vertically the astigmatism makes the focus alarger) is obtained on the entrance of the monochroma-tor. The Czerny-Turner Normal Incidence Monochroma-tor (NIM) optical design has been chosen for the mono-chromator [10]. This design has the most desirable fea-tures when working below 11 eV, namely, resolution,high light-gathering power, simple scanning mechanism,

and the advantages of fixed exit and entrance slits withno deviation in the direction of the exit beam. In this de-sign light from the entrance slit is rendered parallel by aspherical concave mirror and reflected onto an echelleplane grating. A second spherical mirror that collects thediffracted beam and focuses it on the exit slit. The rela-tive energy resolution, assuming that the intrinsic contri-bution coming from the grating is negligible, is given bythe formula: (∆E/E) = δcotθ/2F, where δ is the slit open-ing, F is the focal length of the spherical mirror and θ isthe blaze angle. Using δ = 50 µm, F = 8 m and θ = 70°, weget a relative resolution of 1.1·10-6. We decided to built 8m focal length monochromator to match the best com-promise between needed resolving power and mechani-cal feasibility. The grating used has 52 lines/mm andworks at a blaze angle of 69o (∆E/E = 1.2·10-6). At the exit of the monochromator the beam is impingingon a spherical mirror, which focuses the radiation on thesample on a spot size of about 30 x 100 µm2. A secondspherical mirror is used to collect the radiation scatteredfrom the sample and send it to the entrance slit of theanalyser unit that has the same design as the NIM mono-chromator. The inelastic scattering spectra are collectedby a low noise Peltier-cooled CCD camera placed at the

focal plane of the analyser, which allows to register theinelastic spectrum in one single shot, thus avoiding time-consuming monochromator scans of the diffraction an-gle. The quantum efficiency of the detector is larger than10% for incident energies in the 5 - 15 eV. The momentum transfer can be varied by changing thescattering angle φ and depends on the refraction index ofthe sample n via the formula: Q = (4πn/λ) sin(φ/2) beingλ the incident photons wavelength. The instrumental energy resolution has been measuredby collecting the isotropic scattered intensity from a highroughness copper surface tilted with respect to the beamof about 40o. The measured instrumental relative energyresolution is ∆E/E = 2·10-6 indicating that the obtainedperformance is very close to the theoretical expectation1.7·10-6 given by the convolution of the energy resolutionof the analyser and the one of the monochromator. Fig. 2is a picture of the vacuum chamber containing themonochromator and analyser optics.

WaterWater has always occupied a unique role in the physicsof liquids. Nevertheless, the scenario of properties likethe negative melting volume, the density maximum in

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Fig. 3. Selection of inelastic UV scattering spectra of liquid and super-cooled water (dots), taken at 6.7 eV incident photon energy and 0.09 nm-1

momentum transfer, at the indicated temperatures. The fit lines are su-perimposed. The red line is the experimental resolution.

Fig. 4. Structural relaxation time of water as a function of temperature.Here we compare our IUVS results (solid blue circles) with IXS measure-ment (open squares [5]). The IXS results were interpreted as an Arrheniusbehavior (dotted line). IUVS matches is the best sensitivity condition to su-percooled water timescale below T ~ 280, where IXS becomes evidentlyless reliable. A power-law divergence of τ(T) towards 220 K has been ob-tained, in good agreement with Mode Coupling Theory predictions(MCT) (solid line). In the inset we show the temperature independence ofthe structural stretching parameter (solid diamonds) as foreseen by MCT.

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the normal liquid range -which makes this substance sofundamental in life and earth- as well as the apparent di-vergence of the transport properties in the supercooledtemperature region, is still far from being well settled[11]. Different models have been proposed to explain theanomalous behaviour of water: 1) the existence of twoliquid phases where a second critical point is supposedto be situated in the “no man’s land” temperature region[12,13]; 2) a singularity-free scenario model according towhich the thermodynamic anomalies are ascribed to thepresence of structural heterogeneities [14], and 3) theMode Coupling Theory (MCT) which describes waterfeatures without resorting to an underlying thermody-namic singularity [15]. In this context, the need for ex-perimental evidences, which can discriminate amongthese interpretative models, is evident. Although mea-surements of the S(Q,E) were performed by IXS [5] andBLS [6], a conclusive point was not reached, basicallydue to the fact that the best sensitivity condition (ωPτ ~ 1,where ωP is the frequency of the sound waves probed inthe experiment and τ is the relaxation time) was nevermatched in the supercooled regime. As we will show inthe following, IUVS frequency window matches the con-dition ωPτ ~ 1, allowing a precise determination of therelaxation parameters.We performed IUVS measurements of dynamic structurefactor of high purity H2O between 260 and 340 K, at 6.7eV incident photon energy, and 0.09 nm-1 exchanged mo-mentum. Further details about experimental setup canbe found in [16]. In Fig. 3 we show a selection of IUVS spectra of liquidand supercooled water. The clear broadening of the Bril-louin peaks – which is not resolution limited, as empha-sized by superimposing the resolution function on thespectrum at 302.5 K – is the manifestation of the struc-

tural relaxation process. We analyzed the spectra withthe viscoelastic model for the S(Q,E) [5], in the MCTframework. Details about the analysis are reported else-where [16]; here, we want to stress two main points:MCT foresees a stretched exponential behavior for thedensity autocorrelation function F(Q,t):

F(Q,t) ∝ exp - (t/τ)β (1)

where τ is the characteristic time of a structural relax-ation process and β is the stretching parameter, predict-ed to be less than unity. Moreover, according to MCT, τfollows a power law divergence as a function of temper-ature [15]:

τ(T) ∝ (T–TMCT)–γ (2)

MCT calculations and Molecular Dynamics simulations[17] have estimated the divergence temperature TMCTof water to be in the 220–230 K interval and γ =2.3 ± 0.2. By fitting the model function reported in [16] to the IU-VS spectra, we determined the temperature dependence

Fig. 5. Inelastic ultraviolet scattering spectra of vitreous silica at the indi-cated temperatures. The full lines are the best fit to the data as discussedin the text. The dashed red line represents the instrumental function.

Fig.6. UPPER PANEL: Line-width parameter Γ (~ sound attenuation) inglassy SiO2 as a function of temperature, at Q=0.08 nm-1 (blue circles) andat Q = 0.035 nm-1 (green squares and diamonds). LOWER PANEL: Γ as afunction of the exchanged momentum Q, for vitreous silica at the indi-cated temperatures. UIVS results are reported as blue dots. The dottedlines represent the two distinct Q2 behaviors, which are the best fit toΓ(Q) at high and low Q.

of both the structural relaxation time and the stretchingparameter of liquid and supercooled water. The obtainedvalues are displayed in Fig. 4. Concerning the relaxationtime, the comparison to IXS results of Ref. [5] shows thegood agreement between the two techniques aboveroom temperature. One can appreciate that, below 280 K,IXS values of τ become less reliable, while IUVS datashow a clear deviation from the previous Arrhenius fit(dotted line) of high-temperature IXS data. The MCT power-law expressed in Eq. (2) is able to re-produce the whole dataset of IXS and IUVS τ -values.The power law diverges at TMCT = 220±10 K, and has anexponent γ = 2.3±0.2, in good agreement with previousdeterminations [17]. Moreover, the stretching parameteris temperature independent and close to 0.6, consistentlywith the value of γ as predicted by the MCT [15].Our results strongly support the idea that, at ambientpressure, the divergence of the relaxation time in waterhas a dynamic origin, thus releasing the need of an un-derlying thermodynamic singularity for its explanation.

Vitreous SilicaThe interest towards the attenuation of sound waves inglasses is motivated by the still unsettled problem of thedetermination of its microscopic origin [18]. The acousticabsorption of SiO2 is quite constant with temperatureabove ≈100 K [19] and shows a quadratic dependence onQ both in BLS investigation range [8-10], that is up to Q≈ 0.04 nm-1, and in IXS range [20] 1 - 10 nm-1. The recent model of J.Fabian and P.B.Allen [18], explainsboth the T independence of attenuation and the Q2 be-havior, suggesting that anharmonicity, i.e. the couplingof acoustic modes and thermal vibrations, can inducesound attenuation at ultrasonic and hypersonic frequen-cies. This model is supposed not to extend up to IXS fre-quencies, being limited below ≈100 GHz. The Q2 behav-ior in the THz region, obtained also in harmonic simula-tions of the glass, has been attributed to the topologicaldisorder [20, 21]. A crossover regime in the attenuation mechanism can bethus inferred in the mesoscopic Q-range between 0.04and 1 nm-1, which just corresponds to the IUVS investi-gation domain [7]. We availed ourselves of IUVS the machine to gain infor-mation about sound attenuation in glassy SiO2, in theunexplored region of transferred momentum between0.078 and 0.105 nm-1 [22]. We measured the dynamic structure factor S(Q,E) of SiO2

between 25 and 300 K both using the undulator radia-tion and the 244 nm incident radiation generated by theUV-laser source. In Fig. 5 we show a selection of IUVS spectra. The fulllines are fits to the data; we used a model function madeby the convolution of the experimental resolution func-

tion with a Damped Harmonic Oscillator (DHO) modelfor the inelastic peaks [23].This model for the S(Q,E) gives an appropriate estimateof the linewidth Γ of the Brillouin line both in the liquidand in the glassy state of matter [24]. Γ is simply relatedto the acoustic attenuation coefficient α through the rela-tion Γ = 2α/hc.In the upper panel of Fig.6 we report, as a function oftemperature, the Γ/Q2 values obtained by the analysis ofIUVS data of Fig.3. The values of Γ/Q2 taken from litera-ture are also shown. Fig.6 demonstrates that, above ≈ 130K, where a broad maximum can be inferred, IUVS andBLS data rescale into a single master-plot when Γ is nor-malized to Q2. Moreover Γ(T) as measured by IUVSshows slight temperature dependence below 200 K.These results are in striking agreement with the model ofFabian and Allen for the acoustic attenuation in amor-phous systems, based on the coupling of acousticphonons with thermal vibrations (see Ref. [18], Fig. 2).The smearing out of the peak at ≈ 130 K can be ascribedto the different Q-dependence of its intensity with re-spect to the high temperature plateau [19].In the lower panel of Fig.6 we report the Q dependenceof Γ. We found that the same quadratic dependence de-scribes both BLS and IUVS data up to 0.105 nm-1, whilesuch Q2 behavior, found at low Q’s, does not extrapolateup to IXS points that exhibit a higher attenuation and areevidently shifted up. In fact, the contribution to the at-tenuation from nonlinear effects should reach a plateauabove some 0.1 nm-1[18] while the attenuation in thehigh Q regime should be dominated by topological dis-order [25]. This comparison is the evidence that a change of attenu-ation mechanism occurs between Q=0.105 nm-1 and 1nm-1. Further measurements are currently under devel-opment as a function of Q, in the mesoscopic regionspanned by IUVS, in order to characterize this intriguingchange in regime.

ConclusionsIn conclusion, we have shown the ability of inelastic UVscattering to study the collective dynamics of disorderedsystems in a kinematic region not accessible before. In the case of water we determined the temperature de-pendence of the structural relaxation parameters in thetemperature region where the transport properties startto diverge (i. e. in the undercooled region). The temper-ature behaviour of the structural relaxation time andstretching is in agreement with the mode coupling theo-ry predictions, showing that, at ambient pressure, thedivergence in the transport properties has a dynamicorigin.We have also shown some capabilities of IUVS tech-nique in studying the sound attenuation mechanism in

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amorphous solids. In particular, the results obtained inSiO2 support the anharmonicity model proposed byFabian and Allen [18]. Also in this case, it is evident theunique role of Inelastic Ultra Violet Scattering in access-ing the mesoscopic region, where a change of regime isexpected in SiO2 attenuation coefficient, which cannot berevealed by means of other techniques.

AcknowledgementsWe wish to acknonwledge M. Altarelli for his vision andenthusiastic collaboration in the realization of yhe beam-line project.

References1. J. Jackle, Reports on Progress in Physics 49, 171, (1986). For recent re-

views, see, for instance, Proceedings to the 3rd Workshop on Nonequilib-rium Phenomena in Supercooled Fluids, Glasses and Amorphous Materials,Pisa, Italy, 2002 [Journal of Physics of Condensed Matter; 15, (2003); Pro-ceedings to the 4th International Discussion Meeting in Relaxations inComplex Systems, Hersonissos, Crete, 2001 [Journal of Non-CrystallineSolid 307–310, 1–1080 (2002)]; Proceedings to the 8th International Work-shop on Disordered Systems, Andalo, Italy, 2001, [Philosophical Magazine82, No. 3 (2002)].

2. J.P. Boon and Sidney Yip, Molecular Hydrodynamics (McGraw-Hill,New York, 1980).

3. B. J. Berne and R. Pecora, Dynamic Light Scattering with applications tochemistry, biology and physics (Wiley, New York , 1976).

4. C. Masciovecchio, D. Cocco, A. Gessini, Proceedings of 8th InternationalConference of Synchrotron Radiation Instrumentation, San Francisco, Cali-fornia, 25-29 Aug 2003 (Warwick, American Institute of Physics, 2004),p. 1190.

5. G. Monaco, A Cunsolo, G. Ruocco, F. Sette, Physical Review E 60, 5505,(1999).

6. A. Cunsolo, M. Nardone, Journal of Chemical Physics 105, 3911,(1998).7. G. Ruocco, F. Sette, R. Di Leonardo, D. Fioretto, M. Krisch, M.

Lorentzen, C. Masciovecchio, G. Monaco, F. Pignon, T. Scopigno,Physical Review Letters 83, 5583, (1999).

8. R. Vacher, J. Pelous, Physical Review B 14, 823, (1976).9. T. Tanaka, H. Kitamura; Nucl. Instr. and Meth. in Phys. Res.; A 364, 368,

(1995).10. M. Czerny and A.F. Turner, Z. Physik; 61, 792 (1930).11. O. Mishima, E. Stanley, Nature 396, 329, (1998).12. P.H. Poole, F. Sciortino, U. Essmann, and H.E. Stanley, Nature 360,

324, (1992).13. O. Mishima , H.E. Stanley, Nature 392, 164, (1998).14. P.H. Poole, F. Sciortino, T. Grande, H.E. Stanley, C.A. Angell, Physical

Review Letters 73, 1632 (1994); T.M. Truskett, P.G. Debenedetti, S. Sas-try, S. Torquato, Journal of Chemical Physics 111, 2647, (1999).

15. W. Goetze, L. Sjogren, Reports on Progress in Physics 55, 241, (1992).16. C. Masciovecchio, S.C. Santucci, A. Gessini, S. Di Fonzo, G. Ruocco,

and F. Sette, Physical Review Letters 92, 255507, (2004)17. P. Gallo, F. Sciortino, P. Tagliatesta, S.H. Chen, Phisical Review Letters

76, 2733, (1996). P. F. Sciortino, P. Gallo, P. Tartaglia, S. H. Chen, Physi-cal Review E 54, 6331, (1996). F.W. Starr, M.-C. Bellissent- Funel, H.E.Stanley, Physical Review Letters 82, 3629, (1999). F.W. Starr, F. Sciorti-no, H.E. Stanley, Physical Review E 60, 6757, (1999) .

18. J. Fabian, P.B. Allen, Physical Review Letters 82, 1478,(1999).19. S. Hunklinger and M. v. Schickfus, Amorphous Solids, Low Temperature

Properties (W.A. Phillips Springer-Verlag, Berlin, 1981) pp.81-10520. F. Sette, M. Krisch, C. Masciovecchio, G. Ruocco, G. Monaco, Science

280, 1550, (1998).21. T.S. Grigera, V. Martin-Mayor, G. Parisi, P. Verrocchio, Physical Review

Letters 87, 085502, (2001).22. C. Masciovecchio, A. Gessini, S. Di Fonzo, L. Comez, S.C. Santucci

and D. Fioretto, Physical Review Letters 92, 247401 (2004).23. B. Fak, B. Dorner, Institute Laue Langevin (Grenoble, France), Techni-

cal Report No. 92FA008S, (1992).24. D. Fioretto, L. Comez, G. Socino, L. Verdini, S. Corezzi, P.A. Rolla,

Physical Review E 59, 1899 (1999).25. The role of structural disorder to the attenuation in the 1 and 10 nm-1

region has been recently confirmed by a comparison of IXS spectraobtained from the glass, the poly-crystal and the plastic-crystal phas-es of ethanol. See A. Matic, C. Masciovecchio, D. Engberg, G. Mona-co, L Börjesson, S.C. Santucci and R. Verbeni, Physical Review Letters93, 145502 (2004).

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AbstractBRISP is an Italian-German project for the design, construc-tion and operation of an innovative thermal neutron BRIl-louin SPectrometer installed at the High Flux Reactor of theInstitut Laue-Langevin (ILL, Grenoble). The project has beenfinanced by INFM (Italy) and BMBF (Germany). The spec-trometer exploits the time-of-flight concept to perform neutroninelastic scattering experiments over a wide energy range atlow momentum transfer. Access to this region enables address-ing a number of longstanding scientific questions where ex-periments have not been feasible until now due to the kinemat-ic restrictions of existing neutron spectrometers. The new pos-sibilities offered by BRISP span from the detailed investigationof magnetic dynamics in condensed matter to fluid dynamicsin systems which are close to their liquid-vapour critical point.Installation of all the instrument components has been com-pleted and in last August the first extraction and imaging ofthe monochromatic beam have been accomplished. BRISP willstart its commissioning phase at the beginning of the next Re-actor cycle and it will be available to users by the end of 2005.

Scientific and technical backgroundInelastic scattering of thermal neutrons at low momen-tum transfer represents an ideal tool to measure density-density and spin-spin correlation functions, due to thelinear coupling of the probe to the system. The measure-ment of the cross section related dynamic structure fac-tor S(Q, E) in the region of low wavevector transfer Q isspecially valuable for the investigation of the dynamicbehaviour of disordered and magnetic systems [1-4]. Inthe study of disordered systems, there still exists awavevector transfer region of difficult experimental ac-cess which is enclosed between that characteristic of Bril-louin Light Scattering (Q ~ 0.01 nm-1) and the one typi-cally probed by conventional Inelastic Neutron and X-ray Scattering (Q > 3-5 nm-1, usually). Such a gap limits,for example, the investigation of collective excitations insystems characterized by a relatively high sound veloci-

ty (> 2000 m s-1), which requires also large enough in-coming neutron energies. Regarding magnetic systems,the (Q, E) range accessible to spectroscopic techniques iseven more restricted and inelastic neutron scattering ispractically the only reliable technique for dynamic stud-ies of disordered samples with a small magnetic scatter-ing cross-section. However, the mentioned gap affects al-so the investigation of magnetic systems because of the

magnetic scattering intensity increase on approachingthe Q = 0 limit. The (Q, E) region covered by the differentavailable techniques is shown in Fig. 1.The scientific case and the motivations for accessing thisdynamic region with a clean probe as that representedby inelastic neutron scattering have been widely debatedand are well assessed. Because of the countless applica-tions, we mention only a few scientific examples whichwould greatly benefit from the technical accomplish-

BRISP – A New Thermal Neutron Brillouin ScatteringSpectrometer at the Institut Laue-Langevin

D. Aisaa, E. Babuccia, F. Barocchib, A. Cunsoloc, F. D’Ancac, A. De Francescoc, F. Formisanoc, T. Gahld,E. Guarinib, S. Jahnd, A. Lalonic, H. Mutkae,W.-C. Pilgrimf, A. Orecchinic, C. Petrilloa,*, F. Sacchettia,J.-B. Suckd, G. Venturib

aINFM and Dipartimento di Fisica, Università di Perugia,via A. Pascoli, I-06100 Perugia, ItalybINFM and Dipartimento di Fisica, Università di Firenze ,via G. Sansone 1, I-50019 Sesto Fiorentino, Italy

cINFM Operative Group in Grenoble, 6 rue J. Horowitz,F-38042 Grenoble Cedex 9, FrancedInstitute of Physics, Materials Research and Liquids,TU Chemnitz, 09107 Chemnitz, GermanyeInstitut Laue Langevin, 6 rue J. Horowitz, BP 156,F-38042 Grenoble Cedex 9, FrancefInstitute of Physical Chemistry, Philipps-Universityof Marburg, Germany

Paper received March 2004

Fig. 1 – Region of exchanged wavevector and energy (Q, E) presently ac-cessible to X-ray, neutron and light with the existing instruments. Thegap uncovered by these techniques is apparent.

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ment of a dedicated instrument and refer the reader tothe published literature on the subject [5-9].The study of critical dynamics, with the open question ofthe conjectured breakdown of the universality of trans-port properties, is, for instance, one of the outstandingresearch topics which can be profitably addressed. In-deed, the scattering from critical fluctuations is maxi-mized in the long-wavelength limit, where correlationlength and compressibility diverge [10]. Also, the studyof collective excitations in liquids and compressed gases,with an efficient disentanglement of the purely inelasticfrom the quasi-elastic components of the spectrum, rep-resents an essential contribution to the development ofmeaningful and reliable theoretical models of the liquidstate [5-7,11]. In particular, the investigation of the dy-namic behavior of liquid metals at the atomic scale is ofconsiderable interest because of those peculiar featuresin the excitation spectra that can no longer be interpretedby extending the description of the liquid from classicalhydrodynamics [8]. Understanding the microscopicmechanisms responsible for the propagation and the de-cay of the correlated ionic motions is still a challenge inliquid metals, where the dynamic features cannot be dis-entangled by the interacting electron gas effects. Further,in the study of compressed gases there is a considerableinterest to follow the crossover from hydrodynamic (Q l<< 1, l the mean free path) to kinetic (Q l >> 1) regimeby simply spanning the required Q l range, withoutchanging conditions as important as the thermodynamicstate of the system. In the end, the neutron sensitivity tohydrogen/deuterium could be quite profitably exploitedto characterize the dynamic properties of novel compos-ite materials, biopolymers and proton conductive mem-branes for fuel cells. Experimentally, most of the mentioned research topicscan be tackled only by neutron Brillouin scattering (NBS)or small-angle X-ray inelastic scattering. Indeed, the or-dinary Brillouin scattering of light is affected by impor-tant restrictions due to the very small wavevector of theincident radiation. A well-known shortcoming of this ap-proach is the reduced possibility of reaching high Q lvalues, except for extremely dilute gases. Such limitationpractically prevents one from exploring deviations fromthe hydrodynamic regime, unless undesirable changes ofthe sample thermodynamic conditions are accepted.NBS has the advantage over the X-ray counterpart thatthe incident energy, and with it the energy resolution,can be more easily adapted to the physical problem un-der investigation. In addition, the different shape of theinstrumental resolution function for the two techniques,namely a long-tailed Lorentzian for X-rays and a nearlyGaussian function for neutrons, along with the atomicand mass number independence of the neutron scatter-ing length, which does not limit the study to low Z sam-

ples, make NBS preferable in many cases. As a final note,we remind that the non-destructive nature of the neu-tron scattering technique is a clear benefit when study-ing biological systems.In spite of this, NBS experiments still represent a chal-lenge in the field of neutron spectroscopy, mainly be-cause of either kinematic or beam-time restrictions im-posed by the available instrumentation. So far, NBS mea-surements have been performed on both cold-neutrontime-of-flight (ToF) instruments equipped with a small-angle detection option (like, in the past, the IN5 spec-trometer at the ILL) and three-axis spectrometers (TAS)using thermal neutrons. High-flux ToF instrumentsavailable nowadays no longer allow for dedicated small-angle spectroscopy and, further, the access is often con-fined to a rather restricted dynamical range because ofthe typically low energy of the incoming neutrons. Onthe contrary, three-axis spectroscopy at thermal energies,despite the capability to span a far wider kinematic re-gion, is often a less efficient technique in the study ofisotropic samples, especially when several changes ofthe sample thermodynamic conditions and collection ofextended energy spectra at many different Q values aresimultaneously required. In this respect, beam-time limi-tations with TAS are prohibitive, whereas the ToF tech-nique becomes essential thanks to the intrinsic character-istic of measuring the scattering law at many Q and Evalues simultaneously, without moving any part of theinstrument. The technical limitations which prevent carrying outneutron Brillouin scattering with the existing instru-ments can be overcome by the construction of a dedicat-ed NBS ToF spectrometer capable of combining efficientand flexible small-angle access for low-Q spectroscopy atthermal neutron energies, with good energy resolutionand high counting rate [12,13]. Fulfilling the whole ofthese requirements is quite a difficult task which de-mands a careful optimization of resolution and intensityat the sample. To enable spectroscopic investigations over the 0.1-3 nmspace range and 0.25-5 THz frequency region at the topperformances allowed by the neutron technique, whilesimoultaneously bridging the gap in the kinematic (Q, E)range, a new and unique Brillouin spectrometer hasbeen designed, built and installed at the High Flux Reac-tor of the ILL [14,15]. The project is framed into a CRG(Collaborating Research Group) agreement between ILL,providing the neutron beam, and the partners, responsi-ble for the construction and operation on site of the in-strument with their own personnel. In the year 2000 thetwo partners, the Istituto Nazionale per la Fisica dellaMateria for Italy and the Technical University of Chem-nitz for Germany, signed the agreement with the ILL forthe completion and operation of the neutron BRIllouin

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SPectrometer BRISP. The specific CRG B contract fore-sees that 70% of the available beam time is reserved forexperiments involving the Italian and German scientificcommunity, i.e. concerning research topics leading tosignificant advancements in the various fields of interestof the partners’ countries. This 70% fraction of beam-time is further shared between the Italian and Germancommunity with a 75-25% ratio, respectively. The re-maining 30% of beam-time is managed according to thestandard ILL procedures for public access to instru-ments, with experimental proposals undergoing the usu-al peer-review procedure by the ILL international panels. Considering that in the initial phase of the project theILL was bound only by the condition of providing theneutron beam, and that BRISP was assigned to the 35°-inclined thermal beam tube IH3, exiting at 5 m height inthe ILL reactor hall, the complex preparation of the in-strument site started immediately in 2000. Furtherpreparation works proceeded during 2001, including thedesign and construction of the 4 m-high seism-proofsteel platform that allocates the spectrometer. With theplatform installation coming to an end in mid 2002, andthe definition and development of the main shieldingand spectrometer components, BRISP started an intenseconstruction and assembling phase, along with the par-allel support of a simulation activity for component opti-misation [16,17]. During 2004 imperative objectives ofthe BRISP project have been achieved, reaching goals inthe instrument development as important as the extrac-tion of the monochromatic beam and its first imaging onthe detector [18,19]. Since the signature of the agreement,the development of the BRISP spectrometer has indeedovercome the related technical challenges, while pro-gressively becoming a well-established accomplishmentof a CRG activity at the ILL. As a result, a difficult pro-

ject at the earlier stages of instrument design, is present-ly a real instrument in the final assembling/commission-ing phase. The new perspectives opened by this innova-tory thermal Brillouin spectrometer are manifold: fromthe access to the microscopic ion dynamics of liquidsand glasses with relatively high sound velocities (up to3500 m/s), to spin dynamics studies, and bio-physics ormaterial science applications. The energy and momen-tum transfer ranges available to BRISP with optimisedresolution have a key-role for significant advances inseveral research fields, as enabled by the flexible designof the instrument. BRISP will be operational for users bythe end of 2005, with 154 days per year reserved for thehighlight proposals of the Italian and German scientificcommunities, and more than two months of ILL-man-aged public beam-time, out of total 220 days per yearavailable with the ILL reactor working at the full rate offour cycles per year.

Instrument description and operation principleBRISP is a direct geometry ToF instrument, that is oper-ated at fixed incident energy E0, which is optimized forsmall-angle neutron spectroscopy in the thermal region.The working principle is based on a hybrid spectrometerconfiguration, where incoming neutrons are monochro-matized via Bragg reflection at a multi-crystal focusingmonochromator, which is coupled to a rapidly rotatingFermi chopper enabling a high-resolution ToF analysisof the scattered neutrons. The two-dimensional positionsensitive detector (PSD), presently covering a detectionarea of 1.4 m2, is maintained under vacuum and can betranslated along the incident beam direction between 1.5and 6 m from the sample position. Depending on thesample-to-detector distance, the lower and upper angu-lar limits of 0.6° and 20°, respectively, can be reached.

Fig. 2 - Schematic of the BRISP spectrometer showing the various components of the instrument from the source to the detector. After reflection of the35°-inclined beam at the monochromator, neutrons travel parallel to the ground at 6 m height

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Some of the spectrometer components which have beenespecially designed for BRISP, like the new-concept sec-ond collimator [20], together with the very large area de-tector [15,21] considerably contribute to an outstandingperformance of the instrument. A high signal-to-back-ground ratio is possible only thanks to the under-vacu-um (10-1 mbar) operation of the entire beam-line and tothe careful and optimized shielding of all the sections ofthe instrument which, being installed inside the reactorhall, suffers from the relatively high level of environ-mental neutron and γ-ray radiation. An efficient separa-tion of the different under-vacuum sections of the instru-ment is accomplished by gate valves. The sample cham-ber is kept under the cryogenic vacuum (up to 10-6 mbar)provided by a turbo-molecular pump.The schematic of the spectrometer is shown in Fig. 2 andthe characteristics of the main components are summa-rized in Table I. The overall spatial extension of the spec-trometer, which is mounted on a platform at 4 m abovethe ground, is about 19 m. A graphite insert in the IH3 in-pile beam tube deter-mines the circular cross-section of the beam (6 cm diam-eter). At the exit of the IH3 beam tube an integrated neu-tron intensity of 5 x 1011 n/s is available with an energydistribution peaked at thermal energies and a ratherlong tail of more energetic neutrons extending up to 250meV, approximately. An efficient shielding against fastneutrons in the primary beam, and gamma radiationproduced inside the various materials surrounding thebeam itself, was defined by an extended simulationwork (MCNP code) [22], shaped and mounted. Indeed,the radiological dose rates at the spectrometer controlcabin, that has to be accessible by users during instru-ment operation, must not exceed 2.5 mSv/h, a quite se-vere constraint. The executive design of both the plat-

form and the primary shielding was performed in com-pliance with the latest seismic regulation and safety pro-cedures for nuclear installations. The BRISP primaryshielding is composed of two different units, detachedby a 60 mm safety gap, in order to ensure a mechanicaldecoupling between the instrument, sitting on the plat-form, and the reactor, in case of earthquakes. The firstpart surrounds the IH3 exit on the reactor wall, while thesecond, containing the Soller collimator and the mono-chromator, is placed on the front part of the instrumentplatform. A view of the platform, with the main compo-nents mounted on it, is shown in Fig. 3 while Fig. 4shows a detailed drawing of the primary shielding.A 0.4° collimation of the white beam in the scatteringplane is achieved by a standard Soller collimator. The 35°inclination of the beam tube with respect to the horizon-tal plane fixes the monochromator Bragg angle θB at avalue of 17.5°. Different incident energies can be chosenby using different monochromator crystals or differentorder of reflections. Two of the three planned monochro-mators already exist, that is Cu(111) and PG (see Table I).A third monochromator, Cu(220), is foreseen to furtherextend the dynamical range. The twenty crystals com-posing a single monochromator are mounted on a me-chanical support allowing for the separate orientation ofeach of the crystals. Overall curvatures of the monochro-mator surface can thus be adjusted to reach the focusingcondition (in and normal to the reflection plane), nor-mally at the detector position. A picture of the mono-chromator is given in Fig. 5 while Fig 6 shows the rock-ing curves resulting from the alignment of the PG mono-chromator.A disk chopper, equipped with eight rectangular win-dows and rotating at a maximum frequency of 5000 rpm,produces broad neutron pulses. This device ensures a re-

Fig. 3 – Picture of the anti-seismic platform taken with some of the spectrometer components mounted on it. The primary shielding, the backgroundchopper casemate, and the detector vacuum tank are clearly visible. The detector and its electronic box, not yet installed inside the vacuum chamber, isalso visible on the platform.

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Soller collimator α1 = 0.4°Length 700 mm, slit spacing 5 mm16 Gd2O3 coated kapton sheets, thickness 75 mm

Monochromator Single-face: 20 crystals in a 4x5 matrix, crystal size 40x20 mm2

Average mosaic spread h = 0.5° (expt. 0.4° to 0.6°)Two available monochromators for the selection of 3 incident energies:PG(002): E0 = 20.1 meV (λ0 = 2.02 Å, v0 = 1961 m/s)Cu(111): E0 = 51.9 meV (λ0 = 1.26 Å, v0 = 3151 m/s)PG(004): E0 = 80.3 meV (λ0 = 1.01 Å, v0 = 3919 m/s)A third monochromator is foreseen for 2005:Cu(220): E0 = 138.3 meV (λ0 = 0.77 Å, v0 = 5144 m/s)

Background chopper Disk chopper (480 mm diam.) with 8 rectangular windowsRotation axis parallel to the beamWindows width: 60 mmMaterial: steel with Gd2O3 coatingMaximum rotation frequency: 5000 rpm

Honeycomb α2 = 0.4°multi-beam converging Honeycomb (hexagonal) converging tubes arrangementcollimators [20] Length 2000 mm, tube wall thickness 0.3 mm

Material: Al with Gd2O3 coatingConvergence at 3 possible distances from the sample:a) 2 m - single tube surface 205 mm2 (entrance) and 136 mm2 (exit)b) 4 m - single tube surface 205 mm2 (entrance) and 153 mm2 (exit)c) 6 m - single tube surface 205 mm2 (entrance) and 164 mm2 (exit)

Fermi chopper Magnetically suspended70 (w) x 30 (h) mm2 central openingRotation axis: horizontal, perpendicular to the beamMaterial: steel with Cd coatingMaximum rotation frequency: 15000 rpmInternal Soller collimator: αFC = 1.1°, length 13 mm120 absorbing sheets, slit spacing 0.25 mm

Sample chamber Diameter 500 mm, Height 550 mmAluminum windows, thickness 1 mmMaterial: AlVacuum level 10-6 mbar (with dedicated turbo-molecular pump)Ancillary equipment: Maxi Orange Cryostat (1.5-300 K, sample access 100 mm),furnace (300 - 2000 K, sample access 40 mm)

Detector Type: two-dimensional array of single Reuter-Stockes position sensitive tubes96 3He filled (15 bar) tubes, diameter 12.7 mm, length 1118 mm 1229 (w) x 1118 (h) mm2 detection area (1.4 m2), 13x11 mm2 spatial resolutionIn 2005: upgrade to 128 tubes of 1118 mm length + 32 tubes of 610 mm length, all of 12.7 mm diameter, for a total detection area of 2.1 m2.Mounted with a mechanical support on a long translation stageSample-to-detector distance Dsd: 1.5 to 6 mDetector vacuum tank: cylindrical vessel, diameter 2500 mm, length 8000 mmMaterial: AISI-304 stainless steel

Table I – Characteristics of the BRISP components.

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duction of the background of the continuous beam and,by a proper phasing with the Fermi chopper, minimizescontamination by other-order reflections of the mono-chromator. The second collimator, 2 m long, is based onthe focusing multibeam concept and is equipped withthe recently proposed honeycomb design, specially de-veloped for BRISP [20]. This two-dimensional converg-ing device splits the monochromatic beam into severalcollimated (0.4° divergence) partial beams of decreasinghexagonal cross-section and converging at the detectorposition. This innovatory solution has the important ad-vantage of combining a high transmission of the neutronbeam with simultaneous convergence and collimation inboth the vertical and horizontal scattering plane, as re-quired for an efficient use of a two-dimensional detectorwith good angular resolution in both directions. A photoof the exit side of the honeycomb collimator is presentedin Fig. 7. In order to adapt the beam convergence to dif-ferent positions of the detector, three honeycomb colli-mators are available, optimized for a sample-to-detectordistance Ds-d = 2, 4, and 6 m, respectively. These aremounted on a rotating support which, in a revolver-like

fashion, allows for an easy positioning in the beam of thechosen collimator. A fourth – relaxed – collimation op-tion, consisting only of two Cd diaphragms, is also avail-able for a possible higher intensity request, though at theexpense of energy and Q resolution. An optimal match-ing of the chosen two-dimensional converging collima-tor with the monochromator focusing configuration canbe achieved by varying the curvature of the monochro-mator. After splitting and collimation of the monochro-matic beam, a fast rotating Fermi chopper is used to pro-duce the short neutron pulses needed to improve theToF resolution and to provide the time-reference for theToF analysis. This chopper, provided by the ILL andpresently adapted to the BRISP configuration by a 1.1°internal Soller collimator, will be operated at a maxi-mum angular velocity of 15000 rpm. The high-vacuumsample chamber of 50 cm diameter is separated by 1 mmaluminum windows from the rest of the vacuum line.An Orange cryostat (1.5-300 K) and a furnace (300-2000K) are available for temperature-controlled measure-ments. Finally, a large-area two-dimensional detector,composed of an array of presently 96 3He PSD tubes, is

Fig. 4 – Drawing of the primary shield-ing showing its complex shape and thedifferent materials necessary for an effi-cient shielding of both neutrons andgamma radiation.

SCIENTIFIC REVIEWS

mounted on a translation stage inside a long vacuumchamber (2.5 m diameter, 8 m length), for collection ofthe scattered neutrons at any desired position between1.5 and 6 m from the sample. The spatial resolutionachievable with the PSD tube assembly amounts to 1.3cm horizontally (due to tube distance) and 1.1 cm verti-cally. Fig. 8 shows a schematic of the detector assemblywhile the vacuum chamber inside which the detectorcan move is pictured in Fig. 9.As for all direct geometry ToF spectrometers, each timechannel of the detector at a given scattering angle θ can

be associated with a value of the final neutron energy E1.This is achieved through the knowledge of the flightpaths before (L0, fixed) and after the sample (L1, ad-justable), the incident energy E0, and the total time offlight tF, according to the well known relations:

(1)

where v0 and v1 are the neutron velocities before and af-ter the scattering event, m is the neutron mass, and L1 de-

pends on the sample-to-detector distance and the scat-tering angle through L1 = Dsd / cosθ. Since E0 is fixed,each value of the scattered energy E1 corresponds to adefined energy transfer E = E0 – E1. The ToF analysis ofthe neutrons collected at a given scattering angle thusprovides an entire spectrum Iθ (E) at once. If the sectionof the detector plane with the Debye-Scherrer cone ofopening angle 2θ is completely on the detector surface,as is the case for θ < θmax, the maximum possible intensi-ty is then collected for this scattering angle. Since severalscattering angles can be simultaneously measured, thistechnique allows for a very efficient collection of thewhole energy spectra with varying θ. The measuredspectra are proportional to the double differential crosssection d2σ (θ, E) ⁄ dΩ dE of the sample, which embodiesthe dynamic properties of the system through the dy-namic structure factor S(Q, E) [4].The energy transfer range corresponding to a given ex-changed wavevector Q is determined by the usual kine-matic relation resulting from the combination of energyand momentum conservation:

( )

2

00

12

00

11

1

1

0

0F 22

121

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

−=⎟

⎟⎠

⎞⎜⎜⎝

⎛

−=⇒+=

EmLtLm

vLtLmE

vL

vLt

FF

26


Fig. 5 – Picture of the multi-crystal PG monochromator of BRISP mount-ed on its support for insertion inside the shielding. The 4x5 crystal matrixcomposing the monochromator surface is clearly visible in the insert.

Fig 6 - Experimental rocking curves of the aligned PG(002) monochroma-tor. The curves were obtained by illuminating three different portions,each of dimension 70 mm x 86 mm, of the whole monochromator surface(208 mm x 86 mm). A quite regular and uniform alignment of the 20 crys-tals over the whole monochromator can be deduced, with an overall mo-saic spread ηexpt. = 0.5°.

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(2)

where k0 and k1 are, respectively, the incident and finalneutron wavevectors. Experimentally, the accessible Q-Eregion with neutrons of fixed initial energy E0 is thatcomprised between the two curves derived from Eq. 2at the minimum and maximum available scattering an-gles. As inelastically scattered neutrons can either gain

energy from the sample (v1 > v0) or release energy to thesample (v1 < v0), one has to distinguish neutron energygain from neutron energy loss spectra, which are sepa-rated from each other by the peak of the elastically scat-tered neutrons at E = 0 (v1 = v0). Concerning the neutronenergy gain spectra, there is ideally no upper limit inneutron velocity. If working with a constant time bin ∆t,as it usually happens, the spectra get more and morecompressed with increasing energy transfer, as – due tothe non-linear relation between time and energy – thetime bins correspond to larger and larger energy binswhen progressing towards the start of the time frame(initiated by a pick-up signal from the Fermi chopper).As neutrons cannot lose more energy than they havewhen arriving at the sample, in the neutron energy lossspectra there is an upper limit to the transferable energy(E ≤ E0). This also implies that the neutrons can emergefrom the scattering event having lost nearly all their ini-tial energy in the interaction with the sample. Thesevery slow neutrons, which are spread over many timechannels, will arrive at the detector later than the fastestneutrons from the next chopper pulse, and thus frameoverlap is unavoidable. To reduce this effect, which es-

pecially produces a sloping background in the neutronenergy gain spectra, one either electronically introducesa pause time at the end of the time frame before startingthe next one, thus dropping the neutrons with v1 ≈ ∞, orone suppresses the next pulse by a corresponding phas-ing of the background and the Fermi chopper. In thisway most of the very slow neutrons will fall betweensubsequent chopper pulses and disturb less the neutronenergy gain spectra.A simple, although non-optimized, way of estimatingthe effective energy transfer range consists in assumingthe elastic time-channel tel to lie at half of the maximumavailable time-frame ∆tp. In this case, the maximum en-ergy loss Emax (corresponding to the minimum neutronfinal energy) is determined by the flight-time tel + ∆tp /2. The absolute value of the maximum energy gain,which corresponds to tel-∆tp/2, is far larger than Emax andthe resulting E range is not centered at E = 0. Due to thenon-linear dependence of energy on time, it is generallymore convenient to exploit a non-symmetric time-regis-tration interval around tel, with most of the availabletime-frame devoted to the acquisition of the ToF spectraat tF > tel. With such a choice the measurements can beadjusted to correspond directly to the, as large as possi-ble, symmetric energy transfer range. This can beachieved through the combination of the condition tF

max

- tFmin ≤ ∆tp with the requirement of a symmetric inter-

val in energy transfer (E1max + E1

min = 2 E0). The result-ing fourth-degree equation for the highest (or lowest)admitted time-of-flight value can be solved graphically,for given flight-path, incident energy, and frame width.From this solution, the corresponding E range can be cal-culated, as well as the (asymmetric) positioning of theelastic time-channel in the explored time-range.In the case of BRISP, ∆tp amounts to 2 ms when the Fer-mi chopper rotates at 15000 rpm. This value and the

( ) ( )

000

1021

20

2

10

1cos211

,2

EE

EE

kQ

kkm

EEE

−−⎟⎟⎠

⎞⎜⎜⎝

⎛−+=⇒

−=−=−=

θ

kkkkQQ hhh

Fig. 7 – Exit side of one of the honeycomb collimators.

Fig. 8 – Schematic of the detector assembly. The detector plate, support-ing the 3He tubes, and the nearly cylindrical electronic box mounted onthe trolley are drawn.

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aforementioned criteria for the evaluation of the maxi-mum symmetric energy transfer range, beyond whichunacceptable frame-overlap effects occur, have beenused to derive the values listed in Table II, for the vari-ous incident energies. The total time-of-flight of elastical-ly (E1 = E0) scattered neutrons tel is also reported, at dif-ferent sample-to-detector distances. Though details onthe other quantities involved in the energy transfer eval-uation (e.g. tF

max, tFmin, E1

max, E1min) are not reported for

sake of simplicity, it is worth mentioning that the elastictime-channel typically lies at the very beginning of thetime-window, with usually more than 70-80% of the

frame devoted to time-of-flight values larger than tel.In small-angle instruments, the angular range is typical-ly determined by the sample-to-detector distance, thesize of the detector, and the size of the beam-stop, whichprotects the detector from damage by the direct beam. Ata given detector distance, the beam-stop size determinesthe lowest scattering angle, while the detector maximumsize (diagonal) fixes the highest scattering angle. For thetypical “powder”-like samples to be studied on BRISP,the intensity collected by the two-dimensional detectorat each given scattering angle θ will be recorded over thering resulting from the intersection of the detector sur-face and the Debye-Scherrer cones of semi-aperture q -∆θ⁄ 2 and θ + ∆θ⁄ 2, respectively, in a dartboard-likefashion. Partial rings at the corners of a rectangular-areadetector give access, though with less and less intensityas the corner is approached, to the higher scattering an-gles. By keeping ~1.5 m as a reasonable diagonal size for

acceptably accurate intensity measurements on theBRISP detector, the maximum scattering angles turn outto be 20°, 10°, and 7° at Dsd = 2, 4, 6 m, respectively.Such angular limits will be extended by the addition offurther detector tubes in 2005. The maximum beam-stopsize, namely 136 mm diameter, was estimated by the Mc-Stas simulations of the spectrometer. Such a value corre-sponds to minimum scattering angles of about 2°, 1°,and 0.6°, when Dsd is varied as above. However, theselower angular bounds can be further reduced by adopt-ing a radius-adjustable beam-stop, which is presentlyunder construction. From the angular ranges, an imme-

diate estimate of the wavevector transfers Q that can beprobed with BRISP can be obtained. For example, as-suming a global 1.3 cm space resolution of the detectorand the worst conditions (i.e. Dsd = 2 m, and the small-est nominal angles for a flat detector) for the evaluationof the corresponding angular step (∆θ ~ 0.35°), the low-est Q value results to be between 1.1 and 1.3 nm-1 at 20.1meV incident energy. The reported variation depends onthe suitable energy extension of the data at the chosenvalue for the Q-interpolation. Indeed, the determinationof the dynamic structure factor S(Q, E) from the con-stant-θ measurements of the ToF spectra requires a con-stant-Q interpolation between data collected at differentangles, which unavoidably implies that the minimum ef-fective Q is higher than the lowest instrumentally acces-sible wavevector transfer Qel min. Referring to the aboveexample, at the same 20.1 meV incident energy, the dif-ference in the minimum Q values reduces for longer dis-tances of the detector (6 m), where ∆θ ~ 0.12° at mostand the effective minimum Q cannot exceed the corre-sponding value of the minimum elastic exchangedwavevector Qel min, that is 0.3 nm-1, by more than 3%. The dynamic regions covered by BRISP are shown inFig. 10, for all the possible incoming energies. The fulllines correspond to the results of Eq. 2, at the minimumand maximum scattering angle, respectively. The dashedlines, which represent the linear dispersion E = h cs Q,are also shown in each panel for two example propaga-

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Fig. 9 – The BRISP detector vacuum chamber. Four inspection viewportsare available, one of these is mounted on a larger side flange for rapidmaintenance access. The central flange on the front of the chamber(closed in this photograph) allows for the scattered beam access at thedetector and will be coupled to the instrument vacuum beamlinethrough a pneumatic gate-valve.

E0(meV) ±E(meV), tel(ms) ±E (meV), tel(ms) ±E (meV), tel(ms)

for Dsd=2 m for Dsd=4 m for Dsd=6 m

20.1 ±17.3 , 1.57 ±13.5 , 2.59 ±10.7 , 3.61

51.9 ±48.4 , 0.98 ±42.1 , 1.61 ±36.1 , 2.25

80.3 ±76.5 , 0.79 ±69.2 , 1.30 ±61.3 , 1.81

138.3 ±134.2 , 0.60 ± 125.5 , 0.99 ±115.3 , 1.38

Table II - Maximum energy transfer symmetric ranges accessible withthe incident energies available on BRISP, at three reference sample-to-de-tector distances (Dsd=2, 4, 6 m). The total time of flight of elastically scat-tered neutrons between Fermi chopper and detector, tel, is also reported.

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tion velocities cs. As the incident energy is increasedfrom 20 to 138 meV, excitations propagating with higherand higher velocity become accessible. The monochro-mators presently available on BRISP enable dynamic in-vestigations of systems characterized by a sound veloci-ty up to 2500 m/s. Such a value will be increased to al-most 3300 m/s by means of the new Cu(220) monochro-mator. Finally, the low-Q dynamic ranges probed at thedifferent incident energies of BRISP can be compared inFig. 11. All curves were calculated from Eq. 2, at 1° scat-tering angle. Estimates of the energy resolution lead to∆E/E0 values ranging from 3% (at the lowest incidentenergy and highest sample-detector distance) to 6% (inthe opposite case) [15], as also confirmed by the MCNPand McStas simulations of BRISP [16,17]. Concerning Qresolution, the uncertainties in incident and final neu-tron wavevectors and scattering angle give rise, takingalso sample- and detector-element size into account, to∆Q values below 0.2 (0.5) nm-1 at the lowest (highest) in-cident energy [15].

Neutron test measurementsProgressing of the neutron components installation hasbeen continuously accompanied by the implementationof radiological tests, aimed at measuring the neutronand gamma doses to assess the efficacy of the shielding.With the primary shielding (~25 tons weight) installed,the first neutron tests were about the effective alignmentof the neutron beam and the measurement of the flux be-fore the monochromator position. This was accom-plished by measuring the activation of several gold

disks, 1 cm diameter each, after a five-minutes irradia-tion in the BRISP neutron beam. A set of 25 disks, with acenter-to-center spacing of 2.5 cm horizontally and 3.5cm vertically, was mounted as a 5 x 5 matrix on an alu-minum square support of 15 cm side, in order to mapthe flux at several points over an area of about 165 cm2.The support was placed perpendicular to the beam,roughly at the position corresponding to the exit of theSoller collimator. The results, displayed in Fig. 12, showa fairly good centering of the beam (nominal center atx=7, y=-5 cm, experimental center at x=6.4, y=-5.7 cm)with a maximum measured flux equal to 4.6·109 n s–1

Fig. 10 – Kinematic regions accessed by theBRISP spectrometer at the different incom-ing energies that are (from 20 to 80 meV) orwill be available in a near future (138.3meV). In each frame, the constant-θ curvesare derived from Eq. 2, using the minimum(lower full curve) and maximum (upperfull curve) scattering angle probed withBRISP. The dispersion lines (brokencurves), corresponding to E=h cs Q, are re-ported in each frame for two examplepropagation velocities cs specified in eachplot.

Fig. 11 – Low-Q dynamical region covered by BRISP at the different inci-dent energies selected by the PG and Cu(111) monochromators. Allcurves were calculated from Eq. 2, at 1° scattering angle.

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30


cm–2. The average rate over the beam area is thus of theorder of 1011 n/s. Such intensity is expected to reduce byapproximately a factor 106 at the sample position, due tothe transmission of the various optical components, asestimated by McStas simulations with the PG(002)monochromator and the intermediate honeycomb colli-mator [17]. Further, due to the focusing monochromatorand converging collimator, the beam size at the samplecovers an area of about 10 cm2, thus yielding an expectedflux at the sample of the order of 104 n s-1 cm-2. The most important tests have been carried out in July-August this year, namely the first and successful extrac-tion of the monochromatic beam and the first operation ofthe BRISP detector bank on the monochromatic beam.The flat pyrolitic graphite monochromator, which hadbeen separately characterized and aligned exploiting oneof neutron test facility of the ILL, was installed on BRISP.Optimal extraction of the monochromatic beam requiredjust a fine adjustment of the monochromator orientationand a minor alignment of the Soller collimator. The totalflux was measured using a calibrated 3He monitor. An ex-perimental value of about 2x108 n/s was obtained over asurface of about 15 cm2. The measured peak flux densitywas 1.5x10 7 n/cm2/s, a value quite close to the expecta-tion. The image of the monochromatic beam, as collectedby coupling a CCD camera to a 6Li doped ZnS scintillator,is shown in Fig. 13. During the same test cycle, the BRISPdetector was lifted to the final test position on the upperpart of the platform and positioned in the direct mono-chromatic beam, at about 3m from the monochromator.First neutron pulses, due to background neutrons on theBRISP site, were recorded on the 64 analogue outputs ofthe detector bank and a first picture was obtained afterconnecting the detector to the data acquisition electronics.On opening the beam shutters, the BRISP detector took itsfirst images of the BRISP monochromatic beam with a 10s acquisition time. The image is shown in Fig. 14.

Based on the above flux values, one can give an estimateof typical count rates at the BRISP detector achievablewith the first instrument setup, that is 20.1 meV incidentenergy. For instance, a hollow Vanadium cylinder, 1.5 cmdiameter, 0.2 cm thickness, 4 cm height, is expected togive 2 x 10-2 n s-1, at the elastic time-channel, over the sol-

id angle element subtended by the detection ring corre-sponding to 2° scattering angle. It is worth noting thatthe scattering power of such a sample, of the order of10%, is about the lowest limit used for typical samples,as the multiple scattering intensity in typical NBS experi-ments is near to a constant background. About ten time-channels must be grouped for a rough comparison withthree-axis spectrometers, which typically are set to mea-sure energy spectra with a larger energy step, e.g. 0.2meV. The BRISP count rate over ten time-channels corre-sponds to an acceptable 2.5% statistical accuracy (rough-ly 1450 counts at the peak of the vanadium ToF spectra)in two hours of data-acquisition time. Besides the ab-solute flux values, the power of the ToF technique isclear when one considers that complete ToF spectra atmore than 20 different scattering angles (and conse-quently Q values) can be measured on BRISP at once.Typically, on high-flux three-axis spectrometers operatedfor NBS spectroscopy, a similar accuracy (given the samesample) can be reached in three minutes, though for asingle (Q,w) point. Thus complete spectra (e.g. 20 pointsin E) at 20 different Q values would require twentyhours. In twenty hours of data-acquisition time, BRISP isable to measure the same spectra with better than onepercent accuracy.

Fig. 13 – Image of the monochromatic beam of BRISP obtained using aCCD camera coupled to a 6Li doped ZnS scintillator.

Fig. 12 – Experimental flux distribution at the position of the Soller colli-mator exit, measured on the BRISP beam prior to the collimator installa-tion. The beam center effective positioning can be compared to the nomi-nal center, expected at x = 7, y = -5 cm.

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Concluding remarksDuring the forthcoming commissioning phase of the in-strument, further developments will include the installa-tion of the third monochromator unit (Cu(220)), in order

to provide BRISP with an increased kinematic range ex-tending to higher energy transfers. Although at the ex-pense of intensity, time-resolution can also be improvedby installing a different Soller collimator (length 30 mm,slit spacing 0.3 mm, aFC=0.6°) at the Fermi chopper, in or-der to reduce the pulse width to 6 ms. The use of Gd2O3-coated silicon blades, in place of the present Gd2O3-coat-ed aluminum ones, would also reduce background andspurious small-angle scattering. Another improvement,suggested by the McStas simulation results, can beachieved by substituting the existing rotor of the Fermichopper with a new one having a higher central window(60 mm in place of 30 mm). Such a choice was shown toincrease the simulated intensity by 40%, without appre-ciable changes in resolution and beam size. The exten-sion of the present detector bank to a total of 160 tubes isalready foreseen in 2005, while the possibility of collect-ing also the high-Q scattering can be a further interestingupgrade of the instrument, envisaged as a possible de-velopment. For this reason the sample chamber is al-ready equipped with an appropriate window, glancingat a future wide-angle detector bank to be installed be-side the chamber itself. Finally, a twin background chop-per is foreseen in order to allow for standard mainte-nance of the existing one, without any risk of affectingthe instrument operation cycles.

AcknowledgmentsWe are pleased to acknowledge all the people that are orwere involved in the BRISP project at some stage helping

us to design, construct, install, and simulate the spec-trometer. In particular, we wish to express our gratitudeto the ILL personnel for the valuable assistance, supportand advice we have always received.

References1. Proceedings of the 2nd European Conference on Neutron Scattering,

Physica B 276-278 (2000).2. Proceedings of the ICNS 2001 - International Conference on Neutron

Scattering, Appl. Phys. A S74 (2002).3. Proceedings of the 3rd European Conference on Neutron Scattering,

Physica B350 (2004).4. D. L. Price and K. Sköld in Methods of Experimental Physics, vols. 23 A-

C, (Academic Press, London, 1987).5. J.-B. Suck, Int. J. Mod. Phys. B 7 (1993) 3003.6. P. Verkerk, J. Phys.: Condens. Matter 13 (2001) 7775.7. Proceedings of the Vth EPS Liquid Matter Conference, J. Phys.: Con-

dens. Matter 15, N. 1 (2003).8. Proceedings of the Eleventh International Conference on Liquid and

Amorphous Metals, Journal of Non-Crystalline Solids 312-314 (2002).9. Proceedings of the International Workshop on Disordered Systems,

Philos. Mag. B 82 (2002).10. J. P. Hansen, I. R. McDonald, Theory of Simple Liquids, (Academic

Press, London, 1986).11. U. Balucani, M. Zoppi, Dynamics of the Liquid State (Clarendon Press,

Oxford, 1994).12. H. Mutka, J. Mol. Structure 293 (1993) 321.13. S. Jahn and J.-B. Suck, Nucl. Instr. Meth. A 438 (1999) 452.14. F. Formisano et al., Physica B 350 (2004) e795.15. D. Aisa et al., Nucl. Instr. Meth. A, in press.16. S. Jahn and J.-B. Suck, Appl. Phys. A 74 (2002) S1465.17. G. Venturi et al., J. Neutron Research 11 (2003) 165.18. The BRISP team, “Small-angle spectroscopy at thermal energies: the

BRISP project at ILL”, to be published in the ILL Annual Report 2004.19. See the BRISP web page at http://infmweb.fi.infn.it/BRISP20. C. Petrillo et al., Nucl. Instr. Meth. A 489 (2002) 304.21. P. van Esch et al., Nucl. Instr. Meth. A 526/3 (2004) 493.22. S. Mahling-Ennaoui and S. Jahn, Proceedings of the ILL Millenium

Symposium & European User Meeting, Grenoble 6-7 April 2001, 281.

Fig. 14 – First image of the monochromaticbeam collected on the 3He BRISP detector.

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AbstractThe new neutron source FRM II inGarching has become operational in2004. A large number of instrumentswill serve scientists from Germany andEuropean countries to perform experi-ments with neutrons. In addition apositron source of high intensity isavailable for material science and nu-clear physics. Irradiation facilities forisotope production, activation analysisand transmutation doping complete the

widely spread range of applications ofthe neutron source. The applicationscover a large variety of high technologyfields from basic research, applied sci-ence, medical treatments to industrialproduction. The FRM II has started thescientific program with the first call forproposals in October 2004. Access forEuropean users is granted through theEU framework program 6 (FP6) withinthe neutron muon consortium NMI3.

The Technische UniversitätMünchen operates the new Germanneutron source FRM II in Garchingnear Munich. The highly optimizedreactor produces an unperturbedflux of thermal neutron of 8 x 1014

neutrons/cm2s at a thermal power of20 MW. Special care has been takento optimize the 10 horizontal and 2inclined beam tubes positioned tan-gential to the single fuel element.The heavy water moderator serves

as thermal neutron source. In addi-tion a liquid deuterium cold source(25 K) and a graphite hot source(2300 K) provide neutrons with shift-ed wave lengths. A converter facilityproduced fast neutrons (fission spec-trum) for cancer irradiation and ra-diography. Further radiography andtomography can be performed bymeans of a dedicated cold neutronbeam. Instruments for neutron scatteringare located in the experimental andneutron guide hall (see fig. 1). Theyhave been designed and constructedby scientific groups from all overGermany. These groups originatefrom universities, neutron centersand Max-Planck institutes. After fin-

FRM II in Garching

Type Name InstrumentDiffraction Heidi single crystal diffractometer, hot source

Resi single crystal diffractometer, thermal sourceSpodi powder diffractometer, thermal sourceStress-Spec material science diffractometerRefsans reflectometer for bio-physics Mira reflectometer, long wave length neutrons

Spectroscopy Reseda resonance-spin-echo spectr., cold sourceTofTof time-of-flight spectrometer, cold sourceNRSE-TAS three-axis spectr. Spin-Echo, thermal sourcePuma three-axis spectrometer, thermal sourcePanda three-axis spectrometer, cold source

Positrons Nepomuc positron beam (“open beam port”)Nepomuc-PAES positron auger spectrometerNepomuc-CDB positron defect spectrometer

Radiography Tomography Antares radiography, tomography, cold sourceNectar radiography, tomography, fission source

Particle physics Mephisto cold neutron beam, special experiments

Table I: List of instruments for the first call for proposals

µ & N & SR NEWS

Figure 1 Instruments located in the experimental and neutron guide hall of the FRM II.

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ishing the commissioning phasethese groups will operate the instru-ments and support experimentsfrom guest scientists. External userscan apply twice a year for beam timethrough the Internet portal athttp://user.frm2.tum.de where theycan get additional informations con-cerning the user program. A list ofthe available instruments for the firstcall for proposals is given in table I.

Additional instruments are in thecommissioning phase.In addition to the scientific programthe FRM II serves for industrial(commercial) applications. A silicondoping facility and 17 irradiationchannels are focused on semicon-ductor industry, isotope productionand neutron activation analysis. Aspecial building has been construct-ed with laboratories to be rent by in-

dustrial companies to allow han-dling of the radioactive isotopes onsite. Dedicated instruments for stressand strain analysis, texture analysisas well as radiography are ready toperform industrial investigationswith neutron beams.

Juergen NeuhausFRM II Garching

µ & N & SR NEWS

Two research reactors are operatedat Studsvik about 100 km south ofStockholm on the Baltic Coast. Thereactors are operated commerciallyby a subsidiary of Studsvik AB for arange of activities. The academicuse, for basic research and neutronscattering experimentation is therole of Neutron Research Laboratorythat forms part of Uppsala Universi-ty. The company uses the reactorsfor irradiations, isotope productionand as a recent development forboron neutron capture therapy totreat some carcinomas.The Swedish regulatory authority(SKI) renewed the licences for opera-tion of both the R2 and R2-0 reactorsfor a period of 10 years from 1st July2004. Studsvik can therefore plan foran extended period of use and somedevelopment of facilities. NFL has adistinct characteristic as a universitylaboratory although it also providesfacilities to users from other institu-tions. These users come fromSwedish universities, industry and arange of foreign laboratories. The R-2 reactor operates at 50 MW thermalpower and has a flux in the thermalmoderator of about 2 ? 1014 neutronscm2 s1.A recent review of the activities atNFL has led to a focus on experi-mental activities that are relevant to

the interests of Swedish researchcommunity. Neutron scattering is atool for many disciplines and thelargest user groups comes from theareas of chemistry and materialsscience. For example, in solid statechemistry neutron diffraction isroutine for structure determinationof modern magnetic materials, solidelectrolytes and energy storage sys-tems. The ability to study underservice conditions of high or lowtemperatures, under pressure orwhile undergoing reactions is par-ticularly important. The trend to-wards nanoscience has resulted infewer studies of large single crys-tals. Many modern materials arechosen because intrinsically they donot form large domains or crystals.The installation of a second powderdiffractometer, R2D2, shown in Fig-ure 1 has been driven by growth inthis area.A second major area of growth atNFL is to support interests in softmatter and interface science. A re-flectometer is being installed withcomponents now ready in theshielding tank and progress alreadymade on detector arm, slits etc.There is a large community interest-ed in this activity and we expect thatthis will further enhance the growthin users at Studsvik. Details of all the

instruments at NFL can be found onthe WWW site [2]. A range of scienceis pursued with various instruments.Studies of nanoncrystalline andamorphous materials are very strongparticularly using the multidetector

diffractometer for liquids and amor-phous materials, SLAD. Combina-tion of the complex sample environ-ments such as in-situ hydrogenation

The Swedish Neutron Scattering Laboratory,NFL Studsvik

Figure 1. The newly installed R2D2 diffrac-tometer with a compact design and large detec-tor solid-angle. This is described in a paper byA. Wannberg et al. [1]

µ & N & SR NEWS

34


and work in the chemistry laborato-ry is also very common. An advan-tage of the NFL is very flexible andrapid scheduling. Measurements onsamples that are unstable can bemade very quickly.The NFL staff are employed primari-ly by Uppsala University althoughsome hold joint appointments withother institutions. Very close linkswith research and teaching in arange of university departments arean important and, rather unusual,feature of activities at NFL. Studentsin various science and engineeringprogrammes at most of the majorSwedish universities have the op-portunity to visit Studsvik. Neutronscattering is taught as part of manycourses such as magnetism, structur-al chemistry, crystallography andcolloid science. Neutron techniquesare also the subject of a few special-ist courses. These teaching activitiesare certainly not just for Uppsala

University: we have many under-graduate students visiting for practi-cal sessions of varying duration whoget ‘hands-on’ experience of neutronexperiments and data analysis aswell as lectures either at Studsvik orin their home university. This workhelps greatly to reinforce awarenessof the ease of use and access to neu-trons in the scientific community. The activity at the laboratory coversscience from nuclear physicsthrough to biology and engineering.This short account can not describeall areas and readers can find moreinformation on the WWW where theNFL annual reports are also provid-ed. The work at the laboratory re-ceives support from Swedish fund-ing agencies such as the ResearchCouncil (VR) and various researchfoundations. There is a small contri-bution from the EU-NMI3 accessprogramme (Contract N° RII3-CT-2003-505925) that allows selected ex-

periments of excellent quality fromother countries in the European re-search area to be performed with fi-nancial support. Other experimentscan be performed as collaborationswith NFL or other Swedish scien-tists. This exchange of visitors isvaluable and apart from Europe wehave had visits in the last year fromRussia, Ukraine, Pakistan and China.Newly supported programmes forexchanges with China andBangladesh have been announcedby VR/SIDA.

References1. A. Wannberg, M. Gronrös, A. Mellergård, L-

E. Karlsson, R.G. Delaplane, B. Lebech,Zeitschrift für Kristallographie – in press.

2. NFL web site: http://www.studsvik.uu.se/

Adrian R. RennieNFL Studsvik

Figure 2. A group of students from Chalmers Technical University, Gothenburg learning about a diffractometer in the R2 reactor hall in February 2004.

µ & N & SR NEWS

35


ESRF Section

Latest applications for beam time at theESRFA total of 900 new applications forbeam time arrived at the User Officefor the recent deadline, all of themsubmitted electronically. This com-pares with 752 submitted at thesame period last year, and representsa record number of submissions forthe 1st September deadline.The distribution of proposals acrossmajor scientific areas this reviewround is shown in the figure. Thenine Review Committees assessedthe applications on the basis of sci-entific merit, and recommended pro-jects for beam time on the 30 ESRFand 10 CRG beamlines open to usersduring the first half of 2005.

15th ESRF Users Meeting8-9 February 2005The annual ESRF Users Meeting willbe held on the afternoon of TuesdayFebruary 8 and the morning ofWednesday February 9,and will fea-ture.- a plenary session mainly devoted

to an update of the technical and

strategic long-term options for thefacility;

- parallel scientific sessions, with in-vited talks, status reports from thebeamlines, and open discussionson future improvements;

- a Poster Session; - the prestigious ESRF Young Scien-

tist Award ceremony and talk; - the 2005 Users’ Meeting keynote

speech; - a “hard talk” plenary session

where issues on the present statusand the future of the ESRF will bedebated;

- a special celebration of 10 years ofUser Operation.

Satellite workshops:Synchrotron Radiation in Art andArchaeologySynchrotron radiation techniquesprovide powerful new ways to in-vestigate records of our physical andcultural past. The purpose of thisworkshop is to discuss and explorethe current and potential applica-tions of synchrotron science to prob-lems in archaeology and art conser-vation. It will bring together keymembers of the synchrotron com-

munity and experts in the disci-plines of Archaeology, ArchaeologicaScience, Art Conservation and Mate-rials Science. This interdisciplinaryworkshop aims to report the latestresearch accomplishments, highlightongoing projects and catalyse newinteractions between fields.

New Science with New DetectorsIt is becoming increasingly clear thatthe next major advance in synchro-tron science will come via dramati-cally improved or revolutionary de-tector concepts. This workshop willlook at the future science at synchro-tron radiation facilities and discussthe requirements for the detectionsystems needed.

Future eventsJune 2005 - Workshop on “Non-Crystallographic Phase Retrieval”June 2005 - High Pressure and Syn-chrotron Radiation July 2005 - International Workshopon Radiation Imaging DetectorsIWORID-7

For more information, have a look atwww.esrf.fr

ESRF & ILL Contribution

ILL Section

News from the Scientific Council Overall, the subcommittees allocated2436 days on all instruments (therewere 100 days available for alloca-tion this round). This represents 439accepted proposals out of 598 sub-mitted. Of the 40 Italian proposalssubmitted, 31 received beam timewith a total of 115 days, correspond-ing to 4.7% of the total beam timeavailable. The next Scientific Coun-cil with its subcommittee meetingswill be from 30 to 31 March 2005.

ILL Call for ProposalsThe deadline for proposal submis-sion is Tuesday, 15 February 2005,midnight (European time).Proposal submission is only possi-ble electronically. Electronic Pro-posal Submission (EPS) is possiblevia our Visitors’ Club (http://www.ill.fr, Users & Science, Visitors’Club, or directly at http://vitraill.ill.fr/cv/), once you havelogged in with your personal user-name and password. The detailed guide-lines for the sub-mission of a proposal at the ILL canbe found on the ILL web site:www.ill.fr, Users & Science, User In-formation, Proposal Submission,Standard Submission. The web system will be operational

from 1 January 2005, and it will beclosed on 15 February, at midnight(European time). You will get fullsupport in case of computing hitch-es. If you have any difficulties at all,please contact our web-support([email protected]).

Instruments availableThe following instruments will beavailable for the forthcoming round:• powder diffractometers: D1A,

D1B*, D2B, D20• liquids diffractometer: D4• polarised neutron diffractometers:

D3, D23*• single-crystal diffractometers: D9,

D10, D15*, VIVALDI • large scale structure diffractome-

ters: D19, DB21, LADI• small-angle scattering: D11, D22• reflectometers: ADAM*, D17 • small momentum-transfer diffrac-

tometer: D16• diffuse-scattering spectrometer: D7• three-axis spectrometers: IN1, IN3,

IN8, IN12*, IN14, IN20, IN22*• time-of-flight spectrometers: IN4,

IN5, IN6• backscattering and spin-echo spec-

trometers: IN10, IN11, IN13*,IN15, IN16

• nuclear-physics instruments: PN1,PN3

• fundamental-physics instruments:PF1B, PF2

* Instruments marked with an aster-isk are CRG instruments, where asmaller amount of beam time isavailable than on ILL-funded instru-ments, but we encourage such appli-cations. You will find details of the instru-ments on the web, http://www.ill.fr/index_sc.html.

Scheduling periodThose proposals accepted at the nextround, will be scheduled during theLAST CYCLE in 2005 (50 days). Youare probably already aware of thefact that - due to reinforcement workof the reactor structure - the ILL hasreduced the number of reactor cyclesfrom 4.5 down to 3 cycles per yearuntil 2006.

Reactor Cycles for 2005:Cycle n° 140 From 15/02/2005

To 06/04/2005Cycle n° 141 From 15/04/2005

To 04/06/2005Cycle n° 142 From 15/06/2005

To 04/08/2005Start-ups and shut downs areplanned at 8:30 am

WorkshopsThe following workshops areplanned by the ILL in 2005:Neutron Spin-Echo, September 2005Small Angle Inelastic Neutron Scat-teringIUPAB/EBSA Biophysics Congress,satellite meeting in Montpellier, Au-gust 2005;3rd International Workshop on Nu-clear Fission Product Spectroscopy,May 2005.

Giovanna Cicognani(ILL Scientific Coordinator)

Roselyn Mason(ESRF Users’ Office)

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Common Group photo of ILL Scientific Council and the ESRF Science Advisory Committee.

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MEETING REPORTS

The Annual Conference of the ItalianNeutron Scattering Society (SocietàItaliana di Spettroscopia Neutronica,SISN) took place this year on June8th and 9th in the Hotel MonteConero, a well-known resort on topof Monte Conero, a wonderful nat-ural park, just south of Ancona andfacing the Italian Adriatic coast.More than sixty scientists gathered todiscuss recent Italian activities in thefield of neutron diffraction and scat-tering. The topics covered in the talksranged from hard solid-state to softcondensed matter research. Invitedtalks were given by Valeria Arrighi(Heriot-Watt University, Edinburgh,Scotland), Livia Bove (OGG-INFM,Grenoble, France), Giovanna Cicog-nani (ILL, Grenoble, France), FabrizioFiori (University of Ancona, Italy). This year a short (three-day) intensi-ve school (Giornate Didattiche) wasorganised jointly with the AnnualConference. This initiative was mo-stly devoted to graduate and PhDstudents and to young researchersinterested not only in understan-ding advantages and potentialitiesof the technique on a general basis,but also in finding practical applica-

tions in their own research fields.The topic of this first edition of the“Giornate Didattiche” was: “Dyna-mics of Complex Molecular Systems”.The teachers were Ubaldo Bafile(IFAC-CNR, Firenze), Antonio Deriu(University of Parma), SalvatoreMagazù (University of Messina), Si-mone Melchionna (University of Ro-ma ‘La Sapienza’), Ranieri Rolandi(University of Genova), FrancescoSacchetti (University of Perugia),Marco Zoppi (IFAC-CNR, Firenze).The potentiality of Italian instru-ments at the ILL and at ISIS forstudying the dynamics of complexmolecular systems was also de-scribed in detail:- Ferdinando Formisano (OGG-

INFM, Grenoble) illustrated thestate of art of the Brillouin spec-trometer BRISP, presently undercommissioning a the ILL;

- Francesca Natali (OGG-INFM,Grenoble) presented a comprehen-sive overview of the application tobiological and biophysical studiesof the thermal backscattering spec-trometer IN13 at the ILL;

- Daniele Colognesi (IFAC-CNR,Firenze) reviewed recent investiga-

tions performed with TOSCA, acrystal analyser spectrometer atISIS devoted to vibrational spec-troscopy studies;

- Roberto Senesi (University of roma‘Tor Vergata’) illustrated the appli-cations of deep inelastic scatteringusing the VESUVIO spectrometerat ISIS.

In the afternoon, tutorial sessionswere organised by Alessandro Pacia-roni (University of Perugia) in orderto provide direct contact with datareduction and analysis procedures.Twenty-eight students from differentItalian Universities (Ancona, Firen-ze, Genova, Parma, Palermo, Parma,Perugia and Trento) attended the in-tensive course enjoying also the nat-ural surroundings of the site. Theparticipants judged the initiativevery positively; it will then be repli-cated in the years to come.

Antonio DeriuUniversità di Parma

SISN Annual Conference8 - 9 June 2004 - Monte Conero (Italy)

A workshop on Engineering Appli-cations of Neutrons and SynchrotronRadiation took place on 13-14 Sep-tember at ILL-ESRF in Grenoble,France. The workshop brought to-gether around 100 leading scientistsand engineers who discussed the ap-plication of neutron and synchrotronX-ray central facilities for materialsscience problems. The event was or-

ganised by the FaME38 materials en-gineering facility at ILL-ESRF. The programme included formalpresentations, informal workgroupsessions and an opportunity to meetstaff at the ILL-ESRF materials sci-ence beamlines. The formal presenta-tions were structured into three ses-sions entitled Progress, Complemen-tarity and Applications chaired by

Giovanni Bruno (ILL), Thomas Bus-laps (ESRF) and Darren Hughes(FaME38). The presentations show-cased the state-of-the-art neutronand synchrotron X-ray facilities nowavailable for engineering analysisand highlighted the materials sciencechallenges facing industry today.The keynote presentation in theProgress session was given by Peter

Engineering Applications Workshop at ILL-ESRF13-14 September 2004 - Grenoble (France)

Webster of FaME38. He highlightedthe enormous potential of synchro-tron X-rays and neutrons for the in-vestigation of stresses in engineeringcomponents and showed how the re-cent creation of the FaME38 labora-tory helps to optimise experimentalefficiency. Mike Prime (LANL, USA)presented a technique that he hasdeveloped for measuring residualstress in the keynote talk for theComplementarity session. The ‘Con-tour Method’ measures deformationin an electro-machined surface anduses FE analysis to calculate theoriginal residual stress field. It isparticularly useful when used in as-sociation with neutron or synchro-

tron X-ray measurements to revealthe full stress field in components. Inthe session on Applications, RichardBurguete (Airbus, UK) gave an en-tertaining keynote presentationhighlighting the materials science is-sues currently facing the Europeanaerospace industry. He showed thatfailure analysis may be achieved us-ing rigorous mechanical testing andnon-destructive methods such asneutrons and synchrotron X-rays.The range of topics of the full pro-gramme was diverse, reflecting cur-rent ‘hot’ research topics; residualstress analysis in aircraft wings;near-surface stresses arising frommachining; imaging of bonded joints

in car components; biomedical appli-cations. A number of new collabora-tions between on-site researchersand academic/industrial engineer-ing groups were established duringthe workshop and many more areexpected to develop after the event. The workshop committee would liketo thank everyone who helped withthe event and making it an excitingforum. The Workshop Proceedings,which include abstracts of the oralpresentations and posters, the pro-gramme and a list of participants,are available on the FaME38 website(www.ill.fr/fame38).

Darren Hughes FaME38

38


IEEE NSS/MIC satellite workshop on synchrotronradiation detectorsAcknowledging the impact of syn-chrotron radiation research thisyear’s edition of the IEEE NSS /MICheld October16-22, 2004 in Romeaimed for extending the program inthis field. In this occasion a one-daysatellite workshop on synchrotronradiation detectors was organizedwhich attracted 160 participants. During the past 20 years synchrotronlight sources and the associated opti-cal components developed at a fastpace providing a remarkable increaseof intensity and brightness. Eversince then research with synchrotronradiation has emerged to be one ofthe most powerful tools in almostevery field of science and technology.However, these sources can maintaintheir high level of competitivenessonly if a new generation of x-ray andelectron detectors is developed aswell. Right now we are facing a situ-ation in which it is mostly the detec-tion device that limits the final dataquality. Thus the workshop ad-dressed to a serious problem facedby all synchrotron radiation sources:the lack of appropriate detectors.

In contrast to other areas such ashigh energy physics where the de-tectors are tailored for one specificpurpose / experiment only, in syn-chrotron radiation experiments onehas to deal with a wide range of ex-periments. Therefore it is difficult tospecify detectors which can be uti-lized in recent and future synchro-tron radiation experiments. Howev-er a closer analyzes of detectors usedin other fields such as neutron sci-ence, astrophysics, high-energyphysics or medical imaging showsthat state of the art detectors andelectronics concepts already existwhich could be - with some modifi-cations- well suited for synchrotronradiation applications. On the otherhand some recent synchrotron radia-tion detector concepts could be alsovery useful in other fields such asneutron science. Utilizing thisknowledge pool on a mutual basiscould ensure further exploitation ofmodern sources. Therefore thisworkshop aimed to bring togetherscientist from these fields andhelped to foster interdisciplinary

communication channels betweenthe synchrotron radiation users anddetector developers from the fieldsmentioned above. An overall of 28 oral presentationsand 15 posters gave a rather com-plete overview of the detector devel-opment situation in synchrotron ra-diation covering solid state (pixel)devices, gaseous detectors and spec-troscopic systems. The US perspective in the field wererepresented by S. Gruner, CornellUniversity, presenting recent resultsin analog x-ray pixel array detectors,followed by P.Siddons, BrookhavenNational Lab. describing multi ele-ment silicon detectors for x-ray spec-troscopy and S. Friedrich fromLawrence Livermore National Lab.showing how superconducting tun-nel junctions can be used as high res-olution x-ray detectors. G.E. Derbyshire, CCLRC RutherfordAppleton Lab, C.Hall and B.R. Dob-son from CLRC Daresbury Lab. gavecomplete overview about the out-standing detector development inthe UK. It seems that at present Eu-

MEETING REPORTS

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MEETING REPORTS

rope and especially the UK is thecenter of this activity. C. Norris fromDiamond Light source presentedplans how these developments canbe incorporated in a state of the artsynchrotron light source. M. Kocsis,A. Bravin, J.-C. Labiche and C.Ponchut showed developments atthe European Synchrotron Radia-tion Facility ranging from gaseousdetectors over CCDs to Ge – stripdetectors and Si pixel devices. C. Venanzi, University of Trieste,INFN Trieste and A. Castoldi, Po-litecnico di Milano, presenting multichannel silicon counting devices forx-ray imaging with synchrotron ra-diation demonstrated that Italy inthis field is fairly advanced andplaying internationally a leadingrole. In the frame of the recent con-struction of the Australian Synchro-tron Light source the Australian per-spective were represented by T.F.Beverigde, Monash University andA.B. Rozenfeld, University of Wol-longong. Industrial detector re-search and development were repre-sented by C.Kenney, Molecular Bio-logical Consortium, USA, S.G. An-

gello, Area Detector System Cooper-ation, USA and J. Hendrix, mar-reseach, Germany. The latterdemonstrated an outstanding ad-vanced large area amorphous sele-nium based imager for real-timecrystallography. M.Suzuki, Spring 8, Japan showedthe use of multi channel YAP im-agers in high energy x-ray applica-tions and recent results of the firstlarge area Si pixel detector formacromolecular crystallographywere presented by C.Broenniman,Paul Scherrer Institute. Both detec-tors represent a bridge to neutronscience since they were already usedin both fields. G. Gorini, Universitydi Milano Bicocca, Italy and B.Gebauer, Hahn Meitner Institute,Germany, demonstrated how simi-lar are the concepts in neutron de-tection and x-ray detection. Devel-opments of photon counting devicesbased on MCPs in combination withCMOS pixel chips for ground basedastronomy are well suited for UVsynchrotron radiation applicationsas shown by B.Mikulec, Universityof Geneva, Switzerland.

About 20 researcher of the formerSoviet Union were supported by theINTAS grant no 0369 661 to partici-pate the workshop which gaveL.Shekhtman, Budker Institute forNuclear Physics, Russia the possibil-ity to report on his detector for dy-namic studies of explosion and det-onation waves with synchrotron ra-diation. As in all areas of researchalso detector development relies onyoung researchers. Therefore the or-ganizers are grateful to the IA-SFS(Integrating Activity on Synchrotronand Free Electron Laser Science ofthe European sixth framework pro-gram) for the support of young re-searchers to participate this work-shop. The workshop finished with apresentation of M.Bertolo, Sincro-trone Trieste, Italy about the fund-ing opportunities with in the Euro-pean Sixth frame work program andbeyond which gave rise to stimulat-ing discussions how to join forcesfor future detector developments forsynchrotron radiation and neutronscience.

Ralf Hendrik MenkSincrotrone Trieste

The goal of the various editions of the“School of Neutron ScatteringFrancesco Paolo Ricci” has been ad-vanced training for young Europeanresearchers at post-graduate andpostdoctoral level, typically between25 and 30 years old. Its primary ob-

jective is to present the currentmethodology of static and dynamicneutron scattering techniques to sci-entists using scattering methods atlarge scale facilities. Based on thepositive experience with the six pre-vious editions (1994, 1996, 1998, 2000,2002), this year’s event was again or-ganized at the Hotel “Capo d’Orso”located not far from Palau, a recre-ation centre in the Sardinia coast nearLa Maddalena. The School run fromSeptember 21st through October 2nd

2004. The school was attended by 28students, while lectures were deliv-ered by a total of 23 teachers. It pro-vided a forum for learning and ex-

changing experience in using com-plementary experimental techniques.The School was organised by the As-sociazione “F. P. Ricci” (web sitehttp://www.

Nobel Laureate Prof. R.A. Marcus with someattendees.

School of Neutron Scattering Francesco Paolo Ricci21st September - 2nd October 2004 - Palau

Students and teachers in Palau

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MEETING REPORTS

fis.uniroma3.it/sns_fpr/), with the fi-nancial support of the the Italian Na-tional Research Council, CNR, NMI3- Integrated Infrastructure Initiativefor Neutron Scattering and MuonSpectroscopy, the INFM (Udr Tor Ver-gata) and of four Italian Universities(Milano-Bicocca, Palermo, Roma TorVergata, and Roma Tre). Directors ofthe School were dr. F. Aliotta (CNR,Messina) and prof. R. Triolo (Univer-sità di Palermo). Central theme of theSchool was the application of SmallAngle and Ultra Small Angle Scatter-ing techniques. Leading scientistsfrom Europe and from the UnitedStates drawn from Universities andNational and International Laborato-ries have delivered a total of 55 lec-tures and 2 after dinner Nobel lec-tures, given by Prof. R. A. Marcus,1992 Nobel Laureate. Prof. Marcus, aChemist with great human character-istics coupled to an outstanding sci-entific curriculum, has captured theattention of the School attendees bystrongly motivating them. One morn-ing has been dedicated to the synergybetween Experimental and Computa-tional physics, and the complemen-tarities of neutrons and X-rays hasbeen highlighted. Finally a strongprogram of at least 20 hours of practi-cal sessions has completed the train-ing of the young attendees.The program of the school has fo-cused on the following areas:•The fundamentals of the

interaction of neutrons and X-rayswith matter

•Neutron production andexperimental instrumentation

•Theory and application of variousneutron experimental techniques

•Correction and Analysis ofexperimental data collected atInternational Facilities

Subjects for lectures included: Inter-actions of X-rays and Neutrons withMatter. Neutron Generation and De-tection. Neutron Instrumentation. In-elastic Scattering. Magnetic Scatter-ing. Small Angle Scattering. UltraSmall Angle Scattering. Amorphous

Scattering. In summary, basic infor-mation on data interpretation, on thecomplementarity of the differenttypes of radiation, as well as infor-mation on recent applications anddevelopments were presented. Theschool was successful in providing abroader understanding of scatteringmethods and their application for re-solving structural and dynamic prob-lems. In this respect, the analysis ofthe answers of a questionnaire hand-ed out to the participants for qualityassessment, revealed a positive im-pact on future research activities ofthe attendees. In addition, on the af-ternoon on Friday September 24th

two interesting events took place:Dr. Colin Carlile, Dr. P. Radaelli anddr. M. Agamalian, on behalf of Dr. I.Anderson, gave highlights on theMillennium Program (ILL), on theISIS II target, and on SNS Project,respectively. These presentationsmeant to upgrade information onthe instrumentation which will beavailable in the near future.A Mini Symposium on the applica-tion of atomic and nuclear techniquesfor Conservation, Restoration andPreservation of Cultural Heritage,took place. Local and Regional Au-thorities, together with experts andHigh Level Officials of Academic andResearch Organizations participated.Archaeology and archaeometry aretwo emergent fields in materials sci-ence with an increasing demand ofaccess to neutron and SR-based tech-niques. The purpose of the sympo-sium was to discuss and explore thecurrent and potential applications ofsynchrotron science to problems inarchaeology and art conservation,bringing together key members ofthe neutron and synchrotron commu-nity and experts in the disciplines ofArchaeology, Archaeological Science,Art Conservation and Materials Sci-ence. Speakers reported their latestresearch accomplishments, highlightongoing projects, and catalyse newinteractions between these fields. Thewas to help identify problems in Eu-

ropean Archaeology that can benefitfrom the application of atomic andnuclear techniques. A series of 15minutes presentations covering awide spectrum of techniques used inthe field of Conservation, Restorationand Preservation of Cultural Her-itage solicited the interest of the audi-ence for almost four hours. Organiz-ers of the Symposium were C. An-dreani and G. Cinque of the Univer-sity of Rome Tor Vergata, G. Goriniand M. Martini of University of Mi-lano-Bicocca, A. Granelli of the Uni-versity of Rome “La Sapienza” &LUISS, and V. Coda Nunziante ofCNR, Rome. Professor R. Viale, Presi-dent of “Fondazione Rosselli” andChairman of the Symposium, closedthe Symposium by highlighting thefundamental role that Italy couldhave in the field of Conservation,Restoration and Preservation of Cul-tural Heritage, thanks to its uniquecollection of works of art. His finalremark “Italy has a wealth of culturalheritage unique in the world. Techno-logical innovation in the area of Con-servation, Restoration and Preserva-tion of Cultural Heritage has a greatstrategic interest and deserves atten-tion from the leading political forces”underlined the great appreciation forthe topics discussed. In addition, dr.Colin Carlile, Editor of the Journal ofNeutron Research, in appreciation forthe quality of the presentations, hassuggested to collect all the presenta-tions in a special issue of JNR.Professor Rudolph A. Marcus in hisafter dinner Nobel Conference onSeptember 30th has summarized someof his latest work, connected withsome of the topics discussed in theSchool. Most important, has givenuseful suggestions to the attendeesand has personally signed and pre-sented the Certificate of Attendance. At the end, attendees have been giv-en a form and have been asked to fillit with their grading of the teachingand support activities.

R. Triolo

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MEETING REPORTS

The Consiglio Nazionale delle Ricerche(CNR) supports research activities ofthe Italian Community in the field onNeutron and Muon Scattering. This is along established and highly success-ful collaboration the Italian commu-nity benefit for thanks to the interna-tional agreement between the CNRand CCLRC. It involved the scientif-

ic exploitation and development ofthis world leading pulsed neutronsource ISIS, based at Rutherford Ap-pleton Laboratory (UK). The ItalianPartnership Agreement with ISISwas originally signed in 1985, andhas continued uninterrupted sincethen. It has been highly successfulfor both partners, favouring a re-markable growth of the Italian scien-tific community in this field. The Ital-ian neutron community is nowadayscomposed by about 500 researchers,biologists, biotechnologists, chemists,engineer ’s , geologists, physicistsfrom CNR, other Research Institu-tions and Universities, all togetherconstituting about 25% of non Britishusers of the ISIS facility. In the lastfour years this community has used,on average, about 6.8 % per year (seeFigure 1) of the ISIS beam team. Theaveraged ISIS beam time allocated toItalian teams has been labelled ac-cording to the new CNR thematic ar-eas: 83 % in Material Science (see Fig-ure 2), 6.6 % in Earth Sciences, Envi-ronmental Science and Cultural Her-itage, 8.6 % in Energy and Transport2 % in Manufacturing, Food Science

and Molecular Assembly. In the lasttwenty years the British and Italianteams have also jointly collaboratedin R&D projects on neutron as wellas muon instrumentations, designedand constructed several innovativeneutron and muon instruments andare presently involved in new pro-jects on the target station ISIS II.

More recently, Italian scientists havetaken a strong lead to progress thedevelopment of new detectors anddetector concepts for the benefit of awider European community. The sec-ond target station will provide addi-tional and unique, world-leading ex-perimental facilities for the scientificcommunity, offering an unrivalledpotential for structural and dynami-cal studies of condensed matter us-ing cold neutrons. The research pro-gram will be strongly interdiscipli-nary, with particular emphasis onsoft condensed matter, biological sci-ences and advanced materials. The CCLRC-CNR collaboration pro-vides a continuous vital trainingground and backup for the Italiancommunity of users and to multidis-ciplinary areas of research. Recent

examples of research initiatives thathave benefited from this collabora-tion include investigation on ISIS ofcandidate hydrogen storage tech-nologies, and Italian archaeologicalspecimens - helping scientists under-stand how, and from what they wereconstructed. In some cases the instru-ments are part of a network whichsupports a large campaign of mea-surements and might involve co-op-eration across several similar or com-plementary facilities, and across in-ternational boundaries. For theyounger researchers and PhD stu-dents this represents an excellent op-portunity for multi-national researchco-operation where to develop a cul-ture of cross-border co-operation. Recently an additional opportunityfor Italian scientists working in bothneutron, muon. and Synchrotron Ra-diation (SR) has come along to makethem operate in close collaborationfor R&D research in area such asnovel instrumentation and detectionsfor photon and neutron scatteringand SR. In May 2004 the FAMELabMemorandum of Understanding hasbeen signed. This involves some ofthe leading European institutions op-erating in these areas of research, in-cluding CCLRC (ISIS and Diamond)-UK, ELETTRA I, CNR (INFM)-I,LENS-I, INSTM-I, British-Italian Uni-versities, the Delft University ofTechnology-NL and the SNS (USA).These institutions will collaborate forR&D in instrumentation develop-ment, a critical issue to ensure effi-cient utilisation for the sources andto allow continued development ofmore sophisticated and powerful ex-perimental techniques.

Maria Antonietta RicciChairman of the CNR

Neutron Scattering Committee

Italian use of ISIS

Nov 27 - Dec 2, 2005 SYDNEY, AUSTRALIA

International Conference on Neutron Scattering (ICNS 2005)Contact: Brendan KennedyE-mail: [email protected]: http://www.sct.gu.edu.au/icns2005/

Feb 9 - 11, 2005

Joint ESRF-CNRS Workshop SR2A 2005 - “SynchrotronRadiation in Art and Archaelogy”.

Feb 9 - 11, 2005 GRENOBLE, FRANCE

Conference on EPSRC-ILL Millennium Projects.

Feb 13 - 17, 2005 SAN FRANCISCO, USA

I Symposium on “Neutron Diffraction Characterizationon Mechanical Behavior” TMS Annual Meeting

Feb 14 - 25, 2005 JULICH, GERMANY

36th IFF Spring School: Magnetism goes Nano:Electron Correlations, Spin Transport, Molecular Magnetism

Feb 20 - March 25, 2005 GRENOBLE, FRANCE

European Resarch Course for users of large experimen-tal systems (Deadline for application: 18 October 2004).

Apr 2, 2005 GRENOBLE, FRANCE

Workshop on Reflectometry, Off-specular Scatteringand GISANS Institut Laue Langevin, Grenoble, Francehttp://neutron.neutron-eu.net/n_news/n_calendar_of_events/n-events-2005/694

Apr 18 - 23, 2005 BUDAPEST, HUNGARY

Central European Training School on Neutron ScatteringBudapest, Hungaryhttp://neutron.neutron-eu.net/n_news/n_calendar_of_events/n-events-2005/693

Apr 25 - 29, 2005 SANTA FE, USA

ICANS-XVII Conference on the International Collabo-ration on Advanced Neutron Sources Santa Fe, USA

May 8 - 12, 2005 TENNESSEE, USA

51st International Instrumentation Symposium. Knox-ville, Tennessee, USA.

May 16 - 20, 2005 TENNESSEE, USA

PAC 05. Knoxville, Tennessee, USA.

May 28, 2005 FLORIDA, USA

Annual Meeting of the American Crystallographic As-sociation - ACA 2005 one day software workshop onStructure Solution and Refinement of difficult structu-res using powder diffraction Lake Buena Vista, Florida, USA

May 26 - 28, 2005 GRENOBLE, FRANCE

Spring 2005 Conference on EPSRC-ILL MillenniumProjectsInstitut Laue-Langevin, Grenoble, France

June 20 - July 2, 2005 GRENOBLE, FRANCE

Content Meeting (CONtinuous source Time-of-flight,Evolution, Novelties and Targets for future).

Aug 6 - 13, 2005 OXFORD, UK

International Conference on Muon Spin Rotation, Re-laxation and ResonanceOxford, UK

42


CALENDAR

43


Call for proposals forNeutron Sources

BENSCDeadlines for proposal submission are:15 march 2005 and 15 september 2005

ILLDeadline for proposal submission is:15 february 2005

ISISDeadlines for proposal submission are:16 april 2005 and 16 october 2005

LLB-ORPHEE-SACLAYDeadline for proposal submission is:1 october 2005

SINQDeadlines for proposal submission are:15 may 2005 and 15 november 2005

FZ JuelichDeadline for proposal submission is:1 february 2005.

Call for proposals forSynchrotron Radiation Sources

ALSDeadlines for proposal submission are:15 march 2005 and 1 june 2005

BESSYDeadlines for proposal submission are:15 february 2005 and 4 august 2005

DARESBURYDeadlines for proposal submission are:30 april 2005 and 31 october 2005

ELETTRADeadlines for proposal submission are:28 february 2005 and 31 august 2005

ESRFDeadlines for proposal submission are:1 march 2005 and 1 september 2005

GILDADeadlines for proposal submission are:1 may 2005 and 1 november 2005

HASYLABDeadlines for proposal submission are:1 march, 1 september and 1 december 2005

LUREDeadline for proposal submission is:30 october 2005

MAX-LABDeadline for proposal submission is:february 2005

NSLSDeadlines for proposal submission are:31 january, 31 may and 30 september 2005

CALL FOR PROPOSAL

44


ALS Advanced Light SourceBerkeley Lab, 1 Cyclotron Rd, MS6R2100, Berkeley,CA 94720tel: +1 510.486.7745 fax: +1 510.486.4773http://www-als.lbl.gov/Tipo: D Status: O

ANKAForschungszentrum Karlsruhe Institut fürSynchrotronstrahlung Hermann-von-Helmholtz-Platz 176344 Eggenstein-Leopoldshafen, Germanytel: +49 (0)7247 / 82-6071 fax: +49-(0)7247 / 82-6172http://hikwww1.fzk.de/iss/

APS Advanced Photon SourceBldg 360, Argonne Nat. Lab. 9700 S. Cass Avenue,Argonne, Il 60439, USAtel:+1 708 252 5089 fax: +1 708 252 3222http://epics.aps.anl.gov/welcome.htmlTipo: D Status: C

ASTRIDISA, Univ. of Aarhus, Ny Munkegade, DK-8000 Aarhus,Denmarktel: +45 61 28899 fax: +45 61 20740http://www.aau.dk/uk/nat/isaTipo: PD Status: O

BESSY Berliner Elektronen-speicherring Gessell.fürSynchrotron-strahlung mbHBESSY GmbH, Albert-Einstein-Str.15, 12489 Berlin,Germany,tel +49 (0)30 6392-2999 fax +49 (0)30 6392-2990http://www.bessy.deTipo: D Status: O

BSRL Beijing Synchrotron Radiation Lab.Inst. of High Energy Physics, 19 Yucuan Rd.PO Box 918,Beijing 100039, PR Chinatel: +86 1 8213344 fax: +86 1 8213374http://solar.rtd.utk.edu/~china/ins/IHEP/bsrf/bsrf.htmlTipo: PD Status: O

CAMD Center Advanced Microstructures & DevicesLouisiana State University, Center for AdvancedMicrostructures & Devices, 6980 Jefferson Hwy., BatonRouge, LA 70806tel: (225) 578-8887 fax. (225) 578-6954 Faxhttp://www.camd.lsu.edu/Tipo: D Status: O

CHESS Cornell High Energy Synchr. Radiation SourceWilson Lab., Cornell University Ithaca, NY 14853, USAtel: +1 607 255 7163 fax: +1 607 255 9001http://www.tn.cornell.edu/Tipo: PD Status: O

CLSCanadian Light Source, University of Saskatchewan, 101Perimeter Road, Saskatoon, SK., Canada. S7N 0X4http://www.cls.usask.ca/Tipo:D status:C

DAFNEINFN Laboratori Nazionali di Frascati, P.O. Box 13,I-00044 Frascati (Rome), Italytel: +39 6 9403 1 fax: +39 6 9403304http://www.lnf.infn.it/Tipo:P Status: C

DELTAUniversität Dortmund,Emil Figge Str 74b,44221 Dortmund, Germanytel: +49 231 7555383 fax: +49 231 7555398http://prian.physik.uni-dortmund.de/Tipo: P Status: C

DIAMONDDiamond Light Source Ltd, Rutherford AppletonLaboratory, Chilton, Oxon OX11 0QXhttp://www.diamond.ac.uk/Tipo:D status:C

L U C E D I S I N C R OT R O N ESYNCHROTRON SOURCES WWW SERVERS IN THE WORLD(http://www.esrf.fr/navigate/synchrotrons.html)

FACILITIES

FACILITIES

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ELETTRASincrotrone Trieste S.C.p.A., Strada Statale 14 - Km 163,5in AREA Science Park, 34012 Basovizza, Trieste, Italytel: +39 40 37581 fax: +39 40 226338http://www.elettra.trieste.itTipo: D Status: O

ELSA Electron Stretcher and AcceleratorNußalle 12, D-5300 Bonn-1, Germanytel:+49 288 732796 fax: +49 288 737869http://elsar1.physik.uni-bonn.de/elsahome.htmlTipo: PD Status: O

ESRF European Synchrotron Radiation Lab.BP 220, F-38043 Grenoble, Francetel: +33 476 882000 fax: +33 476 882020http://www.esrf.fr/Tipo: D Status: O

EUTERPECyclotron Lab.,Eindhoven Univ. of Technol, P.O.Box 513,5600 MB Eindhoven, The Netherlandstel: +31 40 474048 fax: +31 40 438060Tipo: PD Status: C

HASYLABNotkestrasse 85, D-2000, Hamburg 52, Germanytel: +49 40 89982304 fax: +49 40 89982787http://www-hasylab.desy.de/Tipo: D Status: O

INDUS Center for Advanced Technology, Rajendra Nagar,Indore 452012, Indiatel: +91 731 64626http://www.ee.ualberta.ca/~naik/accind1.htmlTipo: D Status: C

KEK Photon FactoryNat. Lab. for High Energy Physics, 1-1, Oho,Tsukuba-shi Ibaraki-ken, 305 Japantel: +81 298 641171 fax: +81 298 642801http://www.kek.jp/Tipo: D Status: O

KurchatovKurchatov Inst. of Atomic Energy, SR Center,Kurchatov Square, Moscow 123182, Russiatel: +7 95 1964546Tipo: D Status: O/C

LNLS Laboratorio Nacional Luz SincrotronCP 6192, 13081 Campinas, SP Braziltel.: (+55) 0xx19 3287.4520 fax: (+55) 0xx19 3287.4632http://www.lnls.br/Tipo: D Status: C

LUREBât 209-D, 91405 Orsay ,Francetel: +33 1 64468014; fax: +33 1 64464148http://www.lure.u-psud.frTipo: D Status: O

MAX-LabBox 118, University of Lund, S-22100 Lund, Swedentel: +46 46 109697 fax: +46 46 104710http://www.maxlab.lu.se/Tipo: D Status: O

NSLS National Synchrotron Light SourceBldg. 725, Brookhaven Nat. Lab., Upton, NY 11973, USAtel: +1 516 282 2297 fax: +1 516 282 4745http://www.nsls.bnl.gov/Tipo: D Status: O

NSRL National Synchrotron Radiation Lab.USTC, Hefei, Anhui 230029, PR Chinatel +86-551-5132231,3602034 fax +86-551-5141078http://www.nsrl.ustc.edu.cn/en/enhome.htmlTipo: D Status: O

PohangPohang Inst. for Science & Technol., P.O. Box 125Pohang, Korea 790600tel: +82 562 792696 fax: +82 562 794499http://pal.postech.ac.kr/english.htmlTipo: D Status: C

FACILITIES

46


Siberian SR CenterLavrentyev Ave 11, 630090 Novosibirsk, Russiatel: +7 383 2 356031 fax: +7 383 2 352163http://ssrc.inp.nsk.su/english/load.pl?right=general.htmlTipo: D Status: O

SLSSwiss Light SourceContact address: Paul Scherrer Institut, User Office, CH-5232 Villigen PSI, SwitzerlandTel: +41 56 310 4666 Fax: +41 56 310 3294E-mail [email protected]://sls.web.psi.chTipo: D Status: O

SPring-82-28-8 Hon-komagome, Bunkyo-ku ,Tokyo 113, Japantel: +81 03 9411140 fax: +81 03 9413169http://www.spring8.or.jp/top.htmlTipo: D Status: C

SOLEILCentre Universitaire - B.P. 34 - 91898 Orsay Cedexhttp://www.soleil.u-psud.fr/Tipo: D Status:C

SOR-RING Inst. Solid State PhysicsS.R. Lab, Univ. of Tokyo, 3-2-1 Midori-cho Tanashi-shi,Tokyo 188, Japantel: +81 424614131 ext 346 fax: +81 424615401Tipo: D Status: O

SRC Synchrotron Rad. CenterUniv.of Wisconsin at Madison, 3731 SchneiderDriveStoughton, WI 53589-3097 USAtel: +1 608 8737722 fax: +1 608 8737192http://www.src.wisc.eduTipo: D Status: O

SRRC SR Research Center1, R&D Road VI, Hsinchu Science, Industrial Parc,Hsinchu 30077 Taiwan, Republic of Chinatel: +886 35 780281 fax: +886 35 781881http://www.srrc.gov.tw/Tipo: D Status: O

SSRL Stanford SR Laboratory2575 Sand Hill Road, Menlo Park, California, 94025,USA

tel: +1 650-926-4000 fax: +1 650-926-3600http://www-ssrl.slac.stanford.edu/welcome.htmlTipo: D Status: O

SRS Daresbury SR SourceSERC, Daresbury Lab, Warrington WA4 4AD, U.K.tel: +44 925 603000 fax: +44 925 603174E-mail: [email protected]://www.dl.ac.uk/home.htmlTipo: D Status: O

SURF IIIB119, NIST, Gaithersburg, MD 20859, USAtel: +1 301 9753726 fax: +1 301 8697628http://physics.nist.gov/MajResFac/surf/surf.htmlTipo: D Status: O

TERAS ElectroTechnical Lab.1-1-4 Umezono, Tsukuba Ibaraki 305, Japantel: 81 298 54 5541 fax: 81 298 55 6608Tipo: D Status: O

UVSORInst. for Molecular ScienceMyodaiji, Okazaki 444, Japantel: +81 564 526101 fax: +81 564 547079Tipo: D Status: O

D = macchina dedicata

PD = parzialmente dedicata

P = in parassitaggio

O = macchina funzionante

C = macchina in costruzione

D = dedicated machine

PD = partially dedicated

P = parassitic

O = operating machine

C = machine under construction

FACILITIES

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Atominstitut Vienna (A)Facility: TRIGA MARK IIType: Reactor. Thermal power 250 kW.Flux: 1.0 x 1013 n/cm2/s (Thermal);1.7 x 1013 n/cm2/s (Fast)Address for information:1020 Wien, Stadionallee 2 - Prof. H. RauchTel: +43 1 58801 14111; Fax: +43 1 58801 14199E-mail: [email protected]; http://www.ati.ac.atWap: wap.ati.ac.at

NRU Chalk River LaboratoriesThe peak thermal flux 3x1014 cm-2 sec-1Neutron Program for Materials Research National Research Council Canada Building 459, Station 18 Chalk River Laboratories Chalk River, Ontario - Canada K0J 1J0Phone: 1 - (888) 243-2634 (toll free)Phone: 1 - (613) 584-8811 ext. 3973Fax: 1- (613) 584-4040http://neutron.nrc-cnrc.gc.ca/home.html

Budapest Neutron Centre BRR (H)Type: Reactor. Flux: 2.0 x 1014 n/cm2/sAddress for application forms:Dr. Borbely Sándor, KFKI Building 10,1525 Budapest - Pf 49, HungaryE-mail: [email protected]://www.iki.kfki.hu/nuclear

FRJ-2 Research Reactor in Jülich (D)Type: Dido reactor. Flux: 2 x 1014 n/cm2/sProf. D. Richter, Forschungszentrums Jülich GmbH,Institut für Festkörperforschung,Postfach 19 13, 52425 Jülich, GermanyTel: +49 2461161 2499; Fax: +49 2461161 2610E-mail: [email protected]://www.neutronscattering.de

FRG-1 Geesthacht (D)Type: Swimming Pool Cold Neutron Source.Flux: 8.7 x 1013 n/cm2/sAddress for application forms and informations:Reinhard Kampmann, Institute for Materials Science,Div. Wfn-Neutronscattering, GKSS, Research Centre,21502 Geesthacht, GermanyTel: +49 (0)4152 87 1316/2503; Fax: +49 (0)4152 87 1338E-mail: [email protected]://www.gkss.de

HMI Berlin BER-II (D)Facility: BER II, BENSCType: Swimming Pool Reactor. Flux: 2 x 1014 n/cm2/sAddress for application forms:Dr. Rainer Michaelsen, BENSC,Scientific Secretary, Hahn-Meitner-Insitut,Glienicker Str 100, 14109 Berlin, GermanyTel: +49 30 8062 2304/3043; Fax: +49 30 8062 2523/2181E-mail: [email protected]; http://www.hmi.de/bensc

IBR2 Fast Pulsed Reactor Dubna (RU)Type: Pulsed Reactor.Flux: 3 x 1016 (thermal n in core)Address for application forms:Dr. Vadim Sikolenko,Frank Laboratory of Neutron PhysicsJoint Institute for Nuclear Research141980 Dubna, Moscow Region, Russia.Tel: +7 09621 65096; Fax: +7 09621 65882E-mail: [email protected]://nfdfn.jinr.ru/flnph/ibr2.html

ILL Grenoble (F)Type: 58MW High Flux Reactor.Flux: 1.5 x 1015 n/cm2/sScientific CoordinatorDr. G. Cicognani, ILL, BP 156,38042 Grenoble Cedex 9, FranceTel: +33 4 7620 7179; Fax: +33 4 76483906E-mail: [email protected] and [email protected]; http://www.ill.fr

IPNS Intense Pulsed Neutron at Argonne (USA)for proposal submission by e-mailsend to [email protected] or mail/fax to:IPNS Scientific Secretary, Building 360Argonne National Laboratory,9700 South Cass Avenue, Argonne,IL 60439-4814, USAPhone: 630/252-7820; Fax: 630/252-7722 http://www.pns.anl.gov/

IRI Interfaculty Reactor Institute in Delft (NL)Type: 2MW light water swimming pool.Flux: 1.5 x 1013 n/cm2/sAddress for application forms:Dr. A.A. van Well, Interfacultair Reactor Institut,Delft University of Technology, Mekelweg 15,2629 JB Delft, The NetherlandsTel: +31 15 2784738; Fax: +31 15 2786422E-mail: [email protected]; http://www.iri.tudelft.nl

N E U T R O N INEUTRON SCATTERING WWW SERVERS IN THE WORLD(http://www.isis.rl.ac.uk)

FACILITIES

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ISIS Didcot (UK)Type: Pulsed Spallation Source.Flux: 2.5 x 1016 n fast/sAddress for application forms:ISIS Users Liaison Office, Building R3,Rutherford Appleton Laboratory, Chilton,Didcot, Oxon OX11 0QXTel: +44 (0) 1235 445592; Fax: +44 (0) 1235 445103E-mail: [email protected]; http://www.isis.rl.ac.uk

JAERI (J)Japan Atomic Energy Research Institute,Tokai-mura, Naka-gun,Ibaraki-ken 319-11, Japan.Jun-ichi Suzuki (JAERI);Yuji Ito (ISSP, Univ. of Tokyo);Fax: +81 292 82 59227; Telex: JAERIJ24596http://www.ndc.tokai.jaeri.go.jp/

JEEP-II Kjeller (N)Type: D2O moderated 3.5%enriched UO2 fuel.Flux: 2 x 1013 n/cm2/sAddress for application forms:Institutt for EnergiteknikkK.H. Bendiksen, Managing DirectorBox 40, 2007 Kjeller, NorwayTel: +47 63 806000, 806275; Fax: +47 63 816356E-mail: [email protected]; http://www.ife.no

LLB Orphée Saclay (F)Type: Reactor. Flux: 3.0 x 1014 n/cm2/sLaboratoire Léon Brillouin (CEA-CNRS)Submissio by email at the following address :[email protected]://www-llb.cea.fr/index_e.html

NFL Studsvik (S)Type: 50 MW reactor. Flux: > 1014 n/cm2/sAddress for application forms:Dr. A. Rennie, NFL StudsvikS-611 82 Nyköping, SwedenTel: +46 155 221000; Fax: +46 155 263070/263001E-mail: [email protected]://www.studsvik.uu.se

NIST Research Reactor, Washington, USANational Institute of Standardsand Technology-Gaithersburg,Maryland 20899 USACenter Office:J. Michael Rowe, 6210, DirectorNIST Center for Neutron ResearchE-mail: [email protected]://www.ncnr.nist.gov/

NRI Rez (CZ)Type: 10 MW research reactor.Address for informations:Zdenek Kriz, Scientif SecretaryNuclear Research Institute Rez plc, 250 68 Rez - Czech RepublicTel: +420 2 20941177 / 66173428; Fax: +420 2 20941155E-mail: [email protected] / [email protected]; http://www.nri.cz

PSI-SINQ Villigen (CH)Type: Steady spallation source.Flux: 2.0 x 1014 n/cm2/sContact address: Paul Scherrer InstitutUser Office, CH-5232 Villigen PSI - SwitzerlandTel: +41 56 310 4666; Fax: +41 56 310 3294E-mail: [email protected]; http://sinq.web.psi.ch

SPALLATION NEUTRON SOURCE, ORNL (USA)http://www.sns.gov/

TU Munich FRM, FRM-2 (D)Type: Compact 20 MW reactor.Flux: 8 x 1014 n/cm2/sAddress for information:Prof. Winfried Petry,FRM-II Lichtenbergstrasse 1 - 85747 GarchingTel: 089 289 14701; Fax: 089 289 14666E-mail: [email protected]://www.frm2.tu-muenchen.de

NOTIZIARIONeutroni e Luce di SincrotroneVol. 10 n. 1 2005

EDITORIALC. Andreani

SCIENTIFIC REVIEWSInvestigating large scale structures by combiningsmall angle and ultra small angle neutron scatteringF. Lo Celso, I. Ruffo, A. Riso and V. Benfante

Star-Like polymer solutions studies by light andneutron scatteringG. Di Marco, N. Micali, R. Ponterio, V. Villari and A. Hainemann

Inelastic ultraviolet scattering beamline at ElettraC. Masciovecchio, A. Gessini, S. Di Fonzo and S.C. Santucci

µ &N& SR NEWS

MEETING AND REPORTS

CALENDAR

CALL FOR PROPOSAL

FACILITIES

Vol. 10 n. 1 January 2005 - Aut. Trib. Roma n. 124/96 del 22-03-96 - Sped. Abb. Post. 70% Filiale di Roma - C.N.R. p.le A. Moro 7, 00185 Roma



ISSN 1592-7822


ISSN 1592-7822


NOTIZIARIO Neutroni e Luce di Sincrotrone - Issue 10 n.1, 2005

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