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PowderILLDetectorScan v1¶

Summary ¶

Performs powder diffraction data reduction for D2B and D20 (when doing a detector scan).

Properties ¶

Name	Direction	Type	Default	Description
Run	Input	list of str lists	Mandatory	File path of run(s). Allowed values: [‘nxs’]
NormaliseTo	Input	string	Monitor	Normalise to monitor, or skip normalisation. Allowed values: [‘None’, ‘Monitor’]
CalibrationFile	Input	string		File containing the detector efficiencies. Allowed values: [‘nxs’]
UseCalibratedData	Input	boolean	True	Whether or not to use the calibrated data in the NeXus files.
Output2DTubes	Input	boolean	False	Output a 2D workspace of height along tube against tube scattering angle.
Output2D	Input	boolean	False	Output a 2D workspace of height along tube against the real scattering angle.
Output1D	Input	boolean	True	Output a 1D workspace with counts against scattering angle.
CropNegativeScatteringAngles	Input	boolean	True	Whether or not to crop the negative scattering angles.
HeightRange	Input	dbl list		A pair of values, comma separated, to give the minimum and maximum height range (in m). If not specified the full height range is used.
OutputWorkspace	Output	WorkspaceGroup	Mandatory	Output workspace containing the reduced data.
InitialMask	Input	number	20	Number of pixels to mask from the bottom and the top of each tube before superposition.
FinalMask	Input	number	30	Number of spectra to mask from the bottom and the top of the result of 2D options.
ComponentsToMask	Input	string		Comma separated list of component names to mask, for instance: tube_1, tube_2
ComponentsToReduce	Input	string		Comma separated list of component names to output the reduced data for; for example tube_1
AlignTubes	Input	boolean	True	Align the tubes vertically and horizontally according to IPF.

Description ¶

This algorithm performs the data reduction for the D2B instrument at the ILL, and also for D20 when doing a detector scan.

Provide the list of the input runs, that is the runs corresponding to a single detector scan, following the syntax in MultipleFileProperty. Note that for this algorithm 508093:508095 and 508093-508095 would be equivalent; in either case it will load and process the runs separately and then finally merge them with SumOverlappingTubes.

Calibration ¶

The NeXus files for D2B contain raw data and pre-calibrated data. Either of these can be used when loading. Note that, when reading the calibrated data, the even-numbered tubes will not be flipped, since they are flipped in the nexus files already.

Normalisation Options ¶

The default is for normalisation to monitor, in which case the counts will be scaled up by 10ˆ6 after dividing by monitor counts.

Output ¶

The output from the algorithm is a WorkspaceGroup, containing the requested outputs:

Output2DTubes - Outputs a 2D workspace of tube height against scattering angle. In other words with no correction for Debye-Scherrer cones. It is expected that this is only used for checking alignment.
Output2D - Outputs a 2D workspace of height along tube against scattering angle for pixel in tube. Here there is effectively a correction for the Debye-Scherrer cones.
Output1D - Outputs a 1D workspace of counts against scattering angle. The vertical integration range for this is set in the HeightRange option.

Note for D20 only the Output1D option will be relevant.

For Output2DTubes only the negative scattering angles are included, they are excluded for Output2D and Output1D.

Use SaveFocusedXYE to save in FullProf format #10, or SaveGSS for GSAS format.

Workflow ¶

../_images/PowderILLDetectorScan-v1_wkflw.svg

Usage ¶

Example - PowderILLDetectorScan

red_ws = PowderILLDetectorScan(Run='508093:508095', Output2DTubes=True, Output2D=True, Output1D=True)
print("'2DTubes' output workspace has {0} diffractograms having {1} bins each".format(red_ws[0].getNumberHistograms(), red_ws[0].blocksize()))
print("'2D' output workspace has {0} diffractograms having {1} bins each".format(red_ws[1].getNumberHistograms(), red_ws[1].blocksize()))
print("'1D' output workspace has {0} diffractograms having {1} bins each".format(red_ws[2].getNumberHistograms(), red_ws[2].blocksize()))

Output:

'2DTubes' output workspace has 128 diffractograms having 3024 bins each
'2D' output workspace has 128 diffractograms having 3024 bins each
'1D' output workspace has 1 diffractograms having 3024 bins each

Categories: AlgorithmIndex | ILL\Diffraction | Diffraction\Reduction

Source ¶

Python: PowderILLDetectorScan.py