\(\renewcommand\AA{\unicode{x212B}}\)

ElasticEMUauReduction v1

Summary

Performs an elastic 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, and optional dataset indexes, eg [cycle::] 7333-7341,7345[:0-23]
BackgroundRuns	Input	string		Optional path followed by comma separated range of runs, looking for runs in the sample folder if path not included, eg [cycle::] 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 [cycle::] 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 [cycle::] 6370-6375
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
ScanParameter	Input	string		Display data for time series environment variable, using optional label and units eg T02SP06 [, Temperature, K]
ReferenceRange	Input	string		Normalise the sample counts over the environment or time range. Values are in environment units or secs, eg 75-100
SteppedScanParameter	Input	boolean	False	If the environment variable is set and held during each scan rather than continuosly changing.
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 exchange between incident neutron and sample. Together with knowledge of instrument configuration (distances, angles, and backscattering monochromator velocity) for the detectors, allows assigning momentum transfers to the scattered neutrons, within the instrumental resolution. Normalisation to the flux profile 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.

The elastic neutron scattering data are typically collected while varying temperature or some other scan parameter over real time. Therefore Reduce produces cross section and its estimated error vs momentum transfers and chosen scan parameter.

Workflow

References

Source

Python: ElasticEMUauReduction.py

Categories: AlgorithmIndex | Workflow\Elastic | Workflow\Indirect