4.2

PowderILLDetectorScan v1

../_images/PowderILLDetectorScan-v1_dlg.png

PowderILLDetectorScan dialog.

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.

Input Runs

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.

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 (last modified: 2019-06-25)