SingleCrystalDiffuseReduction v1¶

SingleCrystalDiffuseReduction dialog.

Table of Contents

Summary
Properties
Description
Workflow
Usage
Related Algorithms
Source

Summary ¶

Single Crystal Diffuse Scattering Reduction, normalisation, symmetry and background substraction

Properties ¶

Name	Direction	Type	Default	Description
Filename	Input	list of str lists	Mandatory	Files to combine in reduction. Allowed extensions: [‘_event.nxs’, ‘.nxs.h5’, ‘.nxs’]
Background	Input	string		Background run. Allowed extensions: [‘_event.nxs’, ‘.nxs.h5’, ‘.nxs’]
BackgroundScale	Input	number	1	The background will be scaled by this number before being subtracted.
FilterByTofMin	Input	number	Optional	Optional: To exclude events that do not fall within a range of times-of-flight. This is the minimum accepted value in microseconds. Keep blank to load all events.
FilterByTofMax	Input	number	Optional	Optional: To exclude events that do not fall within a range of times-of-flight. This is the maximum accepted value in microseconds. Keep blank to load all events.
SolidAngle	Input	string	Mandatory	An input workspace containing momentum integrated vanadium (a measureof the solid angle). See MDnormSCD for details. Allowed extensions: [‘.nxs’]
Flux	Input	string	Mandatory	An input workspace containing momentum dependent flux. See MDnormSCD for details. Allowed extensions: [‘.nxs’]
MomentumMin	Input	number	Optional	Minimum value in momentum. The max of this value and the flux momentum minimum will be used.
MomentumMax	Input	number	Optional	Maximum value in momentum. The min of this value and the flux momentum maximum will be used.
UBMatrix	Input	string	Mandatory	Path to an ISAW-style UB matrix text file. See LoadIsawUB. Allowed extensions: [‘.mat’, ‘.ub’, ‘.txt’]
SetGoniometer	Input	boolean	False	Set which Goniometer to use. See SetGoniometer
Goniometers	Input	string	None, Specify Individually	Set the axes and motor names according to goniometers that we define in the code (Universal defined for SNS). Allowed values: [‘None, Specify Individually’, ‘Universal’]
Axis0	Input	string		Axis0: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis1	Input	string		Axis1: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis2	Input	string		Axis2: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
LoadInstrument	Input	string		Load a different instrument IDF onto the data from a file. See LoadInstrument. Allowed extensions: [‘.xml’]
DetCal	Input	string		Load an ISAW DetCal calibration onto the data from a file. See LoadIsawDetCal. Allowed extensions: [‘.detcal’]
MaskFile	Input	string		Masking file for masking. Supported file format is XML and ISIS ASCII. See LoadMask. Allowed extensions: [‘.xml’, ‘.msk’]
SymmetryOps	Input	string		If specified the symmetry will be applied, can be space group name or number, or list individual symmetries.
Uproj	Input	dbl list		Defines the first projection vector of the target Q coordinate system in Q3D mode - Default (1,0,0)
Vproj	Input	dbl list		Defines the second projection vector of the target Q coordinate system in Q3D mode - Default (0,1,0).
Wproj	Input	dbl list		Defines the third projection vector of the target Q coordinate system in Q3D mode. - Default (0,0,1)
BinningDim0	Input	dbl list	-5.05,5.05,101	Binning parameters for the 0th dimension. Enter it as acomma-separated list of values with theformat: ‘minimum,maximum,number_of_bins’.
BinningDim1	Input	dbl list	-5.05,5.05,101	Binning parameters for the 1st dimension. Enter it as acomma-separated list of values with theformat: ‘minimum,maximum,number_of_bins’.
BinningDim2	Input	dbl list	-5.05,5.05,101	Binning parameters for the 2nd dimension. Enter it as acomma-separated list of values with theformat: ‘minimum,maximum,number_of_bins’.
KeepTemporaryWorkspaces	Input	boolean	False	If True the normalization and data workspaces in addition to the normalized data will be outputted
OutputWorkspace	Output	Workspace	Mandatory	Output Workspace. If background is subtracted _data and _background workspaces will also be made.

Developed for CORELLI but should work on any instrument. This workflow algorithm loops over a series of runs combining them with correct normalisation, subtract the background and apply symmetry. The resulting workspace is a MDHistoWorkspace containing a volume of scattering.

The input filename follows the syntax from MultipleFileProperty

This workflow makes use of ConvertToMD and MDNormSCD so these should be reviewed to better understand all the options. An example of creating the Solid Angle and Flux workspaces are included in MDNormSCD. MDNormSCDPreprocessIncoherent can be used to process Vanadium data for the Solid Angle and Flux workspaces.

The resulting workspaces can be saved and loaded with SaveMD and LoadMD respectively.

Masking ¶

The mask from the solid angle workspace is copied to the data. Additional masking is provided by a masking file. A masking file can be created my masking a data file then saving it using SaveMask.

Background ¶

The background is processed the same as the data except that the Goniometer is copied from the data before setting the UB matrix. If a background is included three workspaces are create. If “OutputWorkspace” is set to “ws” you will get the following.

“ws_normalizedBackground” containing the normalised background.

“ws_normalizedData” containing the normalised data.

And “ws” where

$ws = ws\_normalizedData - ws\_normalizedBackground * BackgroundScale$

Should the background scale not be correct this allows you to redo the background subtraction without rerunning the reduction.

If no background is used then the “ws” is just the normalised data.

Symmetries ¶

The symmetry is applied by manipulating the UB matrix. The SymmetryOps parameters can either be defined as a space group (number or name) were all the symmetries for that group is applied, or you can specify individual symmetries to apply.

For example setting SymmetryOps to “P 31 2 1”, “152” or “x,y,z; -y,x-y,z+1/3; -x+y,-x,z+2/3; y,x,-z; x-y,-y,-z+2/3; -x,-x+y,-z+1/3” are equivalent.

Temporary Workspaces ¶

If the KeepTemporaryWorkspaces option is True the data and the normalization in addition to the nomalized data will be outputted. This allows you to run separate instances of SingleCrystalDiffuseReduction and combine the results. They will have names “ws_data” and “ws_normalization” respectively.

Where

$ws\_normalizedData = \frac{ws\_data}{ws\_normalization}$

If background is subtracted there will be similar “ws_background_data” and “ws_background_normalization” for the background.

Where

$ws\_normalizedBackground = \frac{ws\_background\_data}{ws\_backgournd\_normalization}$

Workflow ¶

../_images/SingleCrystalDiffuseReduction-v1.png

Usage ¶

Single file

SingleCrystalDiffuseReduction(Filename='CORELLI_29782',
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              BinningDim0='-10.05,10.05,201',
                              BinningDim1='-10.05,10.05,201',
                              BinningDim2='-0.1,0.1,1')

../_images/SingleCrystalDiffuseReduction_corelli_single.png

Multiple files

SingleCrystalDiffuseReduction(Filename='CORELLI_29782:29817:10',
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              BinningDim0='-10.05,10.05,201',
                              BinningDim1='-10.05,10.05,201',
                              BinningDim2='-0.1,0.1,1')

../_images/SingleCrystalDiffuseReduction_corelli_multiple.png

Single file with symmetry

SingleCrystalDiffuseReduction(Filename='CORELLI_29782',
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              BinningDim0='-10.05,10.05,201',
                              BinningDim1='-10.05,10.05,201',
                              BinningDim2='-0.1,0.1,1',
                              SymmetryOps="P 31 2 1")

../_images/SingleCrystalDiffuseReduction_corelli_single_sym.png

Multiple files with symmetry

SingleCrystalDiffuseReduction(Filename='CORELLI_29782:29817:10',
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              BinningDim0='-10.05,10.05,201',
                              BinningDim1='-10.05,10.05,201',
                              BinningDim2='-0.1,0.1,1',
                              SymmetryOps="P 31 2 1")

../_images/SingleCrystalDiffuseReduction_corelli_multiple_sym.png

Multiple files with symmetry and background substraction

SingleCrystalDiffuseReduction(Filename='CORELLI_29782:29817:10',
                              Background='CORELLI_28124',
                              BackgroundScale=0.95,
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              BinningDim0='-10.05,10.05,201',
                              BinningDim1='-10.05,10.05,201',
                              BinningDim2='-0.1,0.1,1',
                              SymmetryOps="P 31 2 1")

../_images/SingleCrystalDiffuseReduction_corelli_multiple_sym_bkg.png

Reading in elastic Corelli autoreduced data

SingleCrystalDiffuseReduction(Filename=','.join('/SNS/CORELLI/IPTS-15526/shared/autoreduce/CORELLI_'+str(run)+'_elastic.nxs' for run in range(29782,29818,10)),
                              Background='/SNS/CORELLI/IPTS-15796/shared/autoreduce/CORELLI_28124_elastic.nxs',
                              BackgroundScale=0.95,
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              BinningDim0='-10.05,10.05,201',
                              BinningDim1='-10.05,10.05,201',
                              BinningDim2='-0.1,0.1,1',
                              SymmetryOps="P 31 2 1")

../_images/SingleCrystalDiffuseReduction_corelli_multiple_sym_bkg_elastic.png

Defining the axis to be [H,H,0], [H,-H,0], [0,0,L]

SingleCrystalDiffuseReduction(Filename='CORELLI_29782:29817:10',
                              Background='CORELLI_28124',
                              BackgroundScale=0.95,
                              SolidAngle='/SNS/CORELLI/shared/Vanadium/2016B/SolidAngle20160720NoCC.nxs',
                              Flux='/SNS/CORELLI/shared/Vanadium/2016B/Spectrum20160720NoCC.nxs',
                              UBMatrix="/SNS/CORELLI/IPTS-15526/shared/benzil_Hexagonal.mat",
                              OutputWorkspace='output',
                              SetGoniometer=True,
                              Axis0="BL9:Mot:Sample:Axis1,0,1,0,1",
                              Uproj='1,1,0',
                              Vproj='1,-1,0',
                              Wproj='0,0,1',
                              BinningDim0='-7.5375,7.5375,201',
                              BinningDim1='-13.165625,13.165625,201',
                              BinningDim2='-0.1,0.1,1',
                              SymmetryOps="P 31 2 1")

../_images/SingleCrystalDiffuseReduction_corelli_multiple_sym_bkg_HH0.png

Source ¶

Python: SingleCrystalDiffuseReduction.py (last modified: 2017-09-14)