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IndirectAnnulusAbsorption v1

Summary

Calculates indirect absorption corrections for an annulus sample shape.

Properties

Name	Direction	Type	Default	Description
SampleWorkspace	Input	MatrixWorkspace	Mandatory	Sample workspace.
SampleChemicalFormula	Input	string	Mandatory	Sample chemical formula
SampleDensityType	Input	string	Mass Density	Use of Mass density or Number density. Allowed values: [‘Mass Density’, ‘Number Density’]
SampleDensity	Input	number	0.1	Mass density (g/cm^3) or Number density (atoms/Angstrom^3)
SampleInnerRadius	Input	number	0.2	Sample radius
SampleOuterRadius	Input	number	0.25	Sample radius
CanWorkspace	Input	MatrixWorkspace		Container workspace.
UseCanCorrections	Input	boolean	False	Use can corrections in subtraction
CanChemicalFormula	Input	string		Chemical formula for the can
CanDensityType	Input	string	Mass Density	Use of Mass density or Number density. Allowed values: [‘Mass Density’, ‘Number Density’]
CanDensity	Input	number	0.1	Mass density (g/cm^3) or Number density (atoms/Angstrom^3)
CanInnerRadius	Input	number	0.19	Sample radius
CanOuterRadius	Input	number	0.26	Sample radius
CanScaleFactor	Input	number	1	Scale factor to multiply can data
Events	Input	number	5000	Number of neutron events
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The output corrected workspace.
CorrectionsWorkspace	Output	WorkspaceGroup		The corrections workspace for scattering and absorptions in sample.

Description

Calculates and applies corrections for scattering abs absorption in a annular sample for a run on an indirect inelastic instrument, optionally allowing for the subtraction or corrections of the container.

The correction factor workspace is a workspace group containing the correction factors in the Paalman and Pings format, note that only \({A_{s,s}}\) and \(A_{c,c}\) factors are calculated by this algorithm.

Workflow

Usage

Note

To run these usage examples please first download the usage data, and add these to your path. In Mantid this is done using Manage User Directories.

Example - Sample corrections for IRIS:

red_ws = LoadNexusProcessed(Filename='irs26176_graphite002_red.nxs')
can_ws = LoadNexusProcessed(Filename='irs26173_graphite002_red.nxs')

corrected, fact = IndirectAnnulusAbsorption(SampleWorkspace=red_ws,
                                            SampleChemicalFormula='H2-O',
                                            CanWorkspace=can_ws,
                                            CanScaleFactor=0.8,
                                            CanInnerRadius=0.19,
                                            SampleInnerRadius=0.2,
                                            SampleOuterRadius=0.25,
                                            CanOuterRadius=0.26,
                                            Events=200,
                                            Version=1)

ass = fact[0]

print ('Corrected workspace is intensity against %s'
      % (corrected.getAxis(0).getUnit().caption()))

print ('Ass workspace is %s against %s'
      % (ass.YUnitLabel(), ass.getAxis(0).getUnit().caption()))

Output:

Corrected workspace is intensity against Energy transfer
Ass workspace is Attenuation factor against Wavelength

Example - Sample corrections for IRIS:

red_ws = LoadNexusProcessed(Filename='irs26176_graphite002_red.nxs')
can_ws = LoadNexusProcessed(Filename='irs26173_graphite002_red.nxs')

corrected, fact = IndirectAnnulusAbsorption(SampleWorkspace=red_ws,
                                            SampleChemicalFormula='H2-O',
                                            CanWorkspace=can_ws,
                                            CanChemicalFormula='H2-O',
                                            CanInnerRadius=0.19,
                                            SampleInnerRadius=0.2,
                                            SampleOuterRadius=0.25,
                                            CanOuterRadius=0.26,
                                            Events=200,
                                            UseCanCorrections=True,
                                            Version=1)

ass = fact[0]
acc = fact[1]

print ('Corrected workspace is intensity against %s'
      % (corrected.getAxis(0).getUnit().caption()))

print ('Ass workspace is %s against %s'
      % (ass.YUnitLabel(), ass.getAxis(0).getUnit().caption()))

print ('Acc workspace is %s against %s'
      % (acc.YUnitLabel(), acc.getAxis(0).getUnit().caption()))

Output:

Corrected workspace is intensity against Energy transfer
Ass workspace is Attenuation factor against Wavelength
Acc workspace is Attenuation factor against Wavelength

Categories: AlgorithmIndex | Workflow\Inelastic | CorrectionFunctions\AbsorptionCorrections | Workflow\MIDAS

Source

Python: IndirectAnnulusAbsorption.py