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InelasticEMUauReduction v1

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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

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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