Training Workshop in use of Synchrotron Radiation and CCP13 Software for Non-Crystalline Diffraction...
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Transcript of Training Workshop in use of Synchrotron Radiation and CCP13 Software for Non-Crystalline Diffraction...
Training Workshop in use of Synchrotron Radiation and CCP13 Software for Non-
Crystalline Diffraction / Fibre Diffraction
23rd-24th November 1999at
Daresbury Laboratory
Programme - Day 1
Tuesday 23rd November in Conference Room 41:15pm Meet in B-Block Foyer1:30pm Welcome1.40pm - 2.30pm Introduction to Scattering and the
Synchrotron2:30pm – 3:00pm Tea/Coffee3:00pm – 5:00pm Data collection on beamline 8.2
Programme - Day 2
Wednesday 24th November in Lab 1910:15am Meet in B-Block Foyer10.30am – 11:20am Data Reduction Techniques11:20am – 11:40am Coffee/Tea11:40am – 12:30pm Basic Data Analysis
Software (XFIT, CORFUNC, etc)12:30pm – 2:00pm Lunch2:00pm – 3:00pm CCP13 software training in Lab 193:00pm – 3:20pm Tea/Coffee3:20pm – 4:30pm CCP13 software training in Lab 194:30pm Close
Synchrotron Studies
Synchrotron Source.UK - SRS at Daresbury (2nd Generation)Elsewhere - ESRF, ALS, SPring-8, etc. (3rd Generation)Future - Diamond
Daresbury Beamlines for NCD/Fibre Diffraction.16.1, 2.1, 8.2, 7.2 (6.2, 14.1)
Why?Flux Time Resolution - Dynamic studies are possibleSupport Facilities
The SRS at Daresbury
Synchrotron Radiation
Accelerated electrons give out a whole spectrum of radiation from Infra red to Hard x-rays.
Lab source, acceleration is when the electrons slam into the copper anode: Bremsstrahlung.
Synchrotrons use bending magnets, Wigglers and Undulators to bend the electrons.
By bending the electrons you cause them to accelerate towards the orbit centre. The tighter the bend, the more acceleration, the higher the flux.
The SRS operates at 200mA and 2GeV.
acceleration
Scattering - WAXS(but also SAXS)
Bragg’s Law
qd
dn
2sin2
d
Increasing qIncreasing q
Increasing dIncreasing d
beamstop
Small Angle Scattering
Small angle scattering is used to study large structures, Å.
Measurements are made in terms of q, the characteristic variable. (Biologists often use s where q=2s)
2 is the scattering angle, is the wavelength of the radiation.
2.1 and 8.2 use 1.5Å x-rays 16.1 1.4Å, (6.2 will have variable
7.2 uses 1.3Å and 1.5Å and 14.1 1.2 or 1.5Å for fibre diffraction
2
ki
ks
q
Length Scales - Where do SAXS & WAXS fit in?
• SAXS is usually considered to include angles < 1° in practice 0.1 °
• SAXS/WAXS experiments collect standard XRD with SAXS to give small scale resolution• For solution scattering (e.g. DNA and proteins) you are limited to about 10Å resolution
1 10 102 103 104 105 106
WAXS SAXS USAXS
Rayleigh Lorentz Fraunhoffer
SEM
TEM Optical Microscope
AFM/STM
1Å = 10-10m1Å = 10-10m
Å
11m = 10m = 1044ÅÅ
Homopolymer Morphology
L
WAXS (Crystallography) SAXS
Visible Light
Back to Front
F.T.F.T.
F.T.F.T.
Beamline Layout
Monochromator
Mirror
Slit set 1Slit set 2
Slit set 3
Slit set 4
Stations
2.1 SAXS (1-D/ 2-D)8.2 SAXS/ WAXS (1-D)16.1 SAXS (2-D) High Flux6.2 SAXS/ WAXS Variable 7.2 WAXS (2-D)14.1 WAXS (2-D) High Flux
Detectors
* Depending on Local Count rates. Limited by the speed of the readout electronics.† Saturation point of the readout instrumentation. Saturation point of the CCD.
Small Angle Scattering (SAXS)
• O. Glatter and O. Kratky“Small Angle X-Ray Scattering” (Out of Print)
• A. Guinier, G. Fournet, C.B. Walker, K.L. Yudowitch“Small Angle Scattering of X-Rays” (Out of Print)
• L.A. Feigun and D.I. Svergun“Structure Analysis by Small Angle X-Ray & Neutron
Scattering”Nruka, Moscow, 1986, English Translation Ed. G.W. Taylor, Plenum, New York, 1987• H. Brumberger
“Modern Aspects of Small Angle Scattering”, NATO ASI Series, Kluver Academic Press 1993• P. Linder, Th Zemb
“Neutron, Xray & Light Scattering, Introduction to an Investigative tool for Colloidal and Polymeric Systems”
Fibre Diffraction
• Fibre Diffraction Methods, ACS Symposium Series, American Chemical Society, Washington DC, 1980. Eds. A.D. French & K.H. Gardner
• Diffraction of X-Rays by Chain Molecules, B.K. Vainshtein, Elsevier Publishing Company, 1966
Scattering Theory (Simplified)
• Scattering arises from induced dipoles in atomic electrons.
• As the scatterers are approximately the same size as the incident wavelength you get a decay in your scattered signal with angle.
• The general formula is• This can be simplified by integrating over all r=(r1-
r2) that are equal, then by integrating over all the different r.
• This first step gives the auto-correlation function• This is the well known Paterson function.• Putting this back into the general formula gives• This is a Fourier Transform and as such there exists
a reciprocal relationship between r and q. For large r you must measure your scattering at low q.
sin
)(2121
* 21)()()( rriqerrdVdVFFqI
)()()(~211
2 rrdVrp
iqrerdVqI )()( 2
Fourier Transforms
Contact Points
• http://srs.dl.ac.uk/index.htm• http://www.srs.dl.ac.uk/ncd/
http://www.srs.dl.ac.uk/ncd/station21/index.html http://www.srs.dl.ac.uk/ncd/station82/index.html http://www.srs.dl.ac.uk/ncd/station161/index.html http://www.dl.ac.uk/SRS/PX/7_2_manual/man.html
• http://www.dl.ac.uk/SRS/CCP13/main.html• E-mail addresses
http://www.clrc.ac.uk/People/PPR