3.6

SNSPowderReduction v1

../_images/SNSPowderReduction-v1_dlg.png

SNSPowderReduction dialog.

Summary

The algorithm used for reduction of powder diffraction data obtained on SNS instruments (e.g. PG3)

Properties

Name Direction Type Default Description
Instrument Input string PG3 Powder diffractometer’s name. Allowed values: [‘NOM’, ‘BSS’, ‘SNAP’, ‘CNCS’, ‘VULCAN’, ‘CORELLI’, ‘PG3’, ‘MANDI’, ‘TOPAZ’, ‘VIS’, ‘SEQ’, ‘ARCS’]
RunNumber Input int list 0 Number of sample run or 0 for only Vanadium and/or Background
Extension Input string _event.nxs Allowed extensions: [‘_histo.nxs’, ‘_event.nxs’, ‘_runinfo.xml’, ‘.nxs.h5’]
PreserveEvents Input boolean True Argument to supply to algorithms that can change from events to histograms.
Sum Input boolean False Sum the runs. Does nothing for characterization runs
PushDataPositive Input string None Add a constant to the data that makes it positive over the whole range. Allowed values: [‘None’, ‘ResetToZero’, ‘AddMinimum’]
BackgroundNumber Input int list 0 If specified overrides value in CharacterizationRunsFile If -1 turns off correction.
VanadiumNumber Input int list 0 If specified overrides value in CharacterizationRunsFile. If -1 turns off correction.
VanadiumBackgroundNumber Input int list 0 If specified overrides value in CharacterizationRunsFile. If -1 turns off correction.
CalibrationFile Input string Mandatory Allowed extensions: [‘.h5’, ‘.hd5’, ‘.hdf’, ‘.cal’]
CharacterizationRunsFile Input string   File with characterization runs denoted. Allowed values: [‘txt’]
ExpIniFilename Input string   Allowed extensions: [‘.ini’]
UnwrapRef Input number 0 Reference total flight path for frame unwrapping. Zero skips the correction
LowResRef Input number 0 Reference DIFC for resolution removal. Zero skips the correction
CropWavelengthMin Input number 0 Crop the data at this minimum wavelength. Overrides LowResRef.
CropWavelengthMax Input number 0 Crop the data at this maximum wavelength. Forces use of CropWavelengthMin.
RemovePromptPulseWidth Input number 0 Width of events (in microseconds) near the prompt pulse to remove. 0 disables
MaxChunkSize Input number 0 Specify maximum Gbytes of file to read in one chunk. Default is whole file.
FilterCharacterizations Input boolean False Filter the characterization runs using above parameters. This only works for event files.
Binning Input dbl list 0,0,0 Positive is linear bins, negative is logorithmic
ResampleX Input number 0 Number of bins in x-axis. Non-zero value overrides “Params” property. Negative value means logorithmic binning.
BinInDspace Input boolean True If all three bin parameters a specified, whether they are in dspace (true) or time-of-flight (false)
StripVanadiumPeaks Input boolean True Subtract fitted vanadium peaks from the known positions.
VanadiumFWHM Input number 7 Default=7
VanadiumPeakTol Input number 0.05 How far from the ideal position a vanadium peak can be during StripVanadiumPeaks. Default=0.05, negative turns off
VanadiumSmoothParams Input string 20,2 Default=20,2
VanadiumRadius Input number 0.3175 Radius for MultipleScatteringCylinderAbsorption
BackgroundSmoothParams Input string   Default=off, suggested 20,2
FilterBadPulses Input number 95 Filter out events measured while proton charge is more than 5% below average
ScaleData Input number 1 Constant to multiply the data before writing out. This does not apply to PDFgetN files.
SaveAs Input string gsas List of all output file types. Allowed values are ‘fullprof’, ‘gsas’, ‘nexus’, ‘pdfgetn’, and ‘topas’
OutputFilePrefix Input string   Overrides the default filename for the output file (Optional).
OutputDirectory Input string Mandatory  
FinalDataUnits Input string dSpacing Allowed values: [‘dSpacing’, ‘MomentumTransfer’]
SplittersWorkspace Input TableWorkspace   Splitters workspace for split event workspace.
SplitInformationWorkspace Input TableWorkspace   Name of table workspace containing information for splitters.
LowResolutionSpectraOffset Input number -1 If larger and equal to 0, then process low resolution TOF and offset is the spectra number. Otherwise, ignored.
NormalizeByCurrent Input boolean True Normalize by current
CompressTOFTolerance Input number 0.01 Tolerance to compress events in TOF.
FrequencyLogNames Input str list SpeedRequest1,Speed1,frequency Possible log names for frequency.
WaveLengthLogNames Input str list LambdaRequest,lambda Candidate log names for wave length.

Description

About Filter Wall

Filter wall is enabled by setting FilterCharacterizations property to true. Then the _getTimeFilterWall routine is used to build the filter wall from the data defined by SplitInformationWorkspace and SplittersWorkspace properties. Time filter wall is used in _loadData to load data in a certain range of time. Here is how the filter is used:

   1. There is NO filter if filter wall is NONE
   2. There is NO lower boundary of the filter wall if wall[0] is ZERO;
   3. There is NO upper boundary of the filter wall if wall[1] is ZERO;

Usage

This is a worksflow algorithm used to process and the results of scattering experimens on powders on SNS instruments. Its usage sample can be found in Mantid System tests repository.

Categories: Algorithms | Diffraction\Reduction