using diffractometers in spec
Post on 04-Jan-2016
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Using Diffractometersin SPEC
Geometries
fourc, kappa fivec, sixc, psic twoc, w21v, w21h s1d2, s2d2 zaxis ….
Reminder
Diffractometer : working in crystal coordinates: HKL
H,K,L to motor positions: matrix UB A particular geometry gives different modes
of operation.
Motor names are fixed by the geometry• ( and always first in wa… magic! )
A diffraction experiment
Enter lattice parameters: setlat Defining orientation matrix:
– setor0, setor1, or0, or1
Deciding working mode– setmode, freeze– setsector
… and work: – wh, ca, ci,pa, hklscan,kscan...
Operation Modes
Use modes to fix some conditions
freeze
Orientation Matrix
or0, or1 ( setor0, setor1 ) can be entered manually: enterUB or by refinement: ( several reflexions )
• reflex_beg
• reflex
• reflex_end
You can print it
Usage
pa ( show current settings ) wh ( show h,k,l and motor positions ) ca, ci ( calculates and show, no move ) br ( go to brag… 1,0,1)
Scans ( of course )
hklscan and variants • hscan
• kscan
• lscan
Radial scans: ( follow a line )
• hkradial, hlradial, klradial
Circular scans: ( doing an arc )
• hkcircle, hlcircle, hkcircle
More
Save• will put all parameters into a file
• load it with ‘do filename’
Internals
calcA• calculates A[] from HKL
calcHKL• calculates HKL from A[]
• leaves values in H,K and L
Who said pseudo-motors?
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