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IndirectILLReductionFWS v1¶

../_images/ImageNotFound.png — Enable screenshots using DOCS_SCREENSHOTS in CMake¶

Summary ¶

Performs fixed-window scan (FWS) multiple file reduction (both elastic and inelastic) for ILL indirect geometry data, instrument IN16B.

Properties ¶

Name	Direction	Type	Default	Description
Run	Input	list of str lists	Mandatory	Run number(s) of sample run(s). Allowed values: [‘nxs’]
BackgroundRun	Input	list of str lists		Run number(s) of background (empty can) run(s). Allowed values: [‘nxs’]
CalibrationRun	Input	list of str lists		Run number(s) of vanadium calibration run(s). Allowed values: [‘nxs’]
CalibrationBackgroundRun	Input	list of str lists		Run number(s) of background (empty can) run(s) for vanadium run. Allowed values: [‘nxs’]
Observable	Input	string	sample.temperature	Scanning observable, a Sample Log entry
SortXAxis	Input	boolean	False	Whether or not to sort the x-axis
BackgroundScalingFactor	Input	number	1	Scaling factor for background subtraction
CalibrationBackgroundScalingFactor	Input	number	1	Scaling factor for background subtraction for vanadium calibration
BackgroundOption	Input	string	Sum	Whether to sum or interpolate the background runs. Allowed values: [‘Sum’, ‘Interpolate’]
CalibrationOption	Input	string	Sum	Whether to sum or interpolate the calibration runs. Allowed values: [‘Sum’, ‘Interpolate’]
CalibrationBackgroundOption	Input	string	Sum	Whether to sum or interpolate the background run for calibration runs. Allowed values: [‘Sum’, ‘Interpolate’]
MapFile	Input	string		Filename of the detector grouping map file to use. By default all the pixels will be summed per each tube. Use .map or .xml file (see GroupDetectors documentation) only if different range is needed for each tube. Allowed values: [‘map’, ‘xml’]
ManualPSDIntegrationRange	Input	long list	1,128	Integration range of vertical pixels in each PSD tube. By default all the pixels will be summed per each tube. Use this option if the same range (other than default) is needed for all the tubes.
Analyser	Input	string	silicon	Analyser crystal. Allowed values: [‘silicon’]
Reflection	Input	string	111	Analyser reflection. Allowed values: [‘111’, ‘311’]
OutputWorkspace	Output	WorkspaceGroup	Mandatory	Output workspace group
SpectrumAxis	Input	string	SpectrumNumber	The spectrum axis conversion target. Allowed values: [‘SpectrumNumber’, ‘2Theta’, ‘Q’, ‘Q2’]
DiscardSingleDetectors	Input	boolean	False	Whether to discard the spectra of single detectors.
ManualInelasticPeakChannels	Input	long list	-1,-1	The channel indices for the inelastic peak positions in the beginning and in the end of the spectra; by default the maxima of the monitor spectrum will be used for this. The intensities will be integrated symmetrically around each peak.
GroupDetectors	Input	boolean	True	Group the pixels using the range, tube-by-tube (default) or in a custom way; it is not recommended to group the detectors at this stage, in order to get absorption corrections right, however the default value is True for backwards compatibility.

Description ¶

This algorithm performs Fixed Window Scan (FWS) data reduction (both Elastic and Inelastic) for IN16B indirect geometry instrument at ILL. It uses internally the IndirectILLEnergyTransfer algorithm.

Input ¶

Multiple files following the syntax given in MultipleFileProperty.

A WorkspaceGroup that contains as many workspaces as many distinct Doppler’s energy values were present in input files list (including E=0 for EFWS). Each Workspace in the group will have the given observable as the x-axis and as many bins, as many files were given corresponding to the same energy. Y-axis will be detector angle, and the values would be the intensities integrated over the whole spectra (for EFWS) or over the two peaks (symmetric around each peak) at the beginning and the end of the spectra (for IFWS). Scanning observable can be any numeric or time-stamp-like string parameter. See sample.* or e.g. start_time in Sample Logs. BackgroundRun s, CalibrationBackgroundRun s and CalibrationRun s will be averaged (default) or interpolated over all the observable points according to the option. Interpolation is provided by SplineInterpolation, which does cubic spline (or linear for 2 points only) interpolation inside the range and flat extrapolation beyond the range. For the moment it does not give errors on interpolated results. Interpolated subtraction or calibration is recommended only if there is a strong dependence on the observable and many measured points in the data to be interpolated.

Workflow ¶

Usage ¶

Example: EFWS+IFWS

ws = IndirectILLReductionFWS(Run='ILL/IN16B/083072:083077.nxs')
print("Result is now a WorkspaceGroup, which has {:d} workspaces, one per each energy value".format( ws.getNumberOfEntries()))
print("first item, called {} corresponds to energy value of {}".format(
ws.getItem(0).name(),ws.getItem(0).name().split('_')[1]))
print("it has {:d} histograms and {:d} bins, one per each temperature".format(
ws.getItem(0).getNumberHistograms(),ws.getItem(0).blocksize()))

Output:

Result is now a WorkspaceGroup, which has 3 workspaces, one per each energy value
first item, called ws_0.0_red corresponds to energy value of 0.0
it has 18 histograms and 2 bins, one per each temperature

Source ¶

Python: IndirectILLReductionFWS.py