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InelasticEMUauReduction v1

Summary

Performs an inelastic energy transfer reduction for ANSTO EMU indirect geometry data.

See Also

IndirectILLEnergyTransfer

Properties

Name	Direction	Type	Default	Description
SampleRuns	Input	str list	Mandatory	Comma separated range of sample runs, eg [cycle::] 7333-7341,7345
BackgroundRuns	Input	string		Optional path followed by comma separated range of runs, looking for runs in the sample folder if path not included, eg [path::] 6300-6308
CalibrationRuns	Input	string		Optional path followed by comma separated range of runs, looking for runs in the sample folder if path not included, eg [path::] 6350-6365
BackgroundCalibrationRuns	Input	string		Optional path followed by comma separated range of runs, looking for runs in the sample folder if path not included, eg [path::] 6370-6375
IncidentSpectrumRuns	Input	string		Optional path followed by comma separated range of runs, looking for runs in the sample folder if path not included, eg [path::] 6375-6385
SpectrumAxis	Input	string	TubeNumber	The spectrum axis conversion target. Allowed values: [‘TubeNumber’, ‘2Theta’, ‘Q’, ‘Q2’]
SampleTransmissionFactor	Input	number	1	Scaling factor for background subtraction from sample
CalibrationTransmissionFactor	Input	number	1	Scaling factor for background subtraction from calibration
OutputWorkspace	Output	Workspace	Mandatory	Name for the reduced workspace.
ScratchFolder	Input	string		Path to save and restore merged workspaces.
KeepIntermediateWorkspaces	Input	boolean	False	Whether to keep the intermediate sample and calibration workspaces for diagnostic checks.
ConfigurationFile	Input	string		Optional: INI file to override default processing values. Allowed values: [‘ini’]
UseFractionalMap	Input	boolean	True	Allocate a fractional of the detector counts area

Description

The purpose of data reduction is to convert the measured spectra into neutron scattering double differential cross sections. That is, the scattering probability given a certain momentum and energy exchange between incident neutron and sample. Together with knowledge of instrument configuration (distances, angles, and backscattering monochromator velocity), observed times of arrival at the detectors allow assigning momentum and energy transfers to the scattered neutrons, within the instrumental resolution. Normalisation to the incident neutron velocity spectrum is further required to obtain a probability.

The Reduce routine thus performs the above necessary algebra on the specified run numbers. At a minimum, the sample runs are needed. Additional runs for background subtraction and joint detector efficiency / solid angle correction are normally provided as well, with Reduce applied to each group separately, and the groups combined as shown in the diagram.

Neutron data collection times imply that inelastic scattering data typically consist in fixed-temperature spectra where the energy transfer is scanned, such that Reduce produces cross section and its estimated error vs energy and momentum transfers.

Workflow

Usage

test = InelasticEMUauReduction('20985', SpectrumAxis='Q', OutputWorkspace='test', ConfigurationFile='emu_doctest.ini')
print('Workspaces in group = {}'.format(test.getNumberOfEntries()))
gp = test.getNames()
print('First workspace: {}'.format(gp[0]))

Workspaces in group = 2
First workspace: test_Q_1D

References

Source

Python: InelasticEMUauReduction.py

Categories: AlgorithmIndex | Workflow\Inelastic | Inelastic\Indirect | Inelastic\Reduction