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

ElasticEMUauReduction v1

../_images/ImageNotFound.png

Enable screenshots using DOCS_SCREENSHOTS in CMake

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

../_images/ImageNotFound.png

diagram generation was disabled

References

Source

Python: ElasticEMUauReduction.py

Categories: AlgorithmIndex | Workflow\Elastic | Workflow\Indirect