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