3.6

CylinderPaalmanPingsCorrection v1

../_images/CylinderPaalmanPingsCorrection-v1_dlg.png

CylinderPaalmanPingsCorrection dialog.

Summary

Calculates absorption corrections for a cylindrical or annular sample using Paalman & Pings format.

Properties

Name Direction Type Default Description
SampleWorkspace Input MatrixWorkspace Mandatory Name for the input sample workspace
SampleChemicalFormula Input string Mandatory Sample chemical formula
SampleNumberDensity Input number 0.1 Sample number density in atoms/Angstrom3
SampleInnerRadius Input number 0.05 Sample inner radius
SampleOuterRadius Input number 0.1 Sample outer radius
CanWorkspace Input MatrixWorkspace   Name for the input container workspace
CanChemicalFormula Input string   Container chemical formula
CanNumberDensity Input number 0.1 Container number density in atoms/Angstrom3
CanOuterRadius Input number 0.15 Can outer radius
BeamHeight Input number 3 Height of the beam at the sample.
BeamWidth Input number 2 Width of the beam at the sample.
StepSize Input number 0.002 Step size for calculation
Interpolate Input boolean True Interpolate the correction workspaces to match the sample workspace
Emode Input string Elastic Emode: Elastic or Indirect. Allowed values: [‘Elastic’, ‘Indirect’]
Efixed Input number 1 Analyser energy
OutputWorkspace Output WorkspaceGroup Mandatory The output corrections workspace group

Description

Calculates absorption corrections for a cylindrical or annular sample giving output in the Paalman & Pings absorption factors: A_{s,s} (correction factor for scattering and absorption in sample), A_{s,sc} (scattering in sample and absorption in sample and container), A_{c,sc} (scattering in container and absorption in sample and container) and A_{c,c} (scattering and absorption in container).

Restrictions on the input workspace

The input workspace must have a fully defined instrument that has X axis units of wavelength.

Usage

Example:

# Create a sample workspace
sample = CreateSampleWorkspace(NumBanks=1, BankPixelWidth=1,
                               XUnit='Wavelength',
                               XMin=6.8, XMax=7.9,
                               BinWidth=0.1)

# Copy and scale it to make a can workspace
can = CloneWorkspace(InputWorkspace=sample)
can = Scale(InputWorkspace=can, Factor=1.2)

# Calculate absorption corrections
corr = CylinderPaalmanPingsCorrection(SampleWorkspace=sample,
                                      SampleChemicalFormula='H2-O',
                                      SampleInnerRadius=0.05,
                                      SampleOuterRadius=0.1,
                                      CanWorkspace=can,
                                      CanChemicalFormula='V',
                                      CanOuterRadius=0.15,
                                      BeamHeight=0.1,
                                      BeamWidth=0.1,
                                      StepSize=0.002,
                                      Emode='Indirect',
                                      Efixed=1.845,
                                      Version=1)

print 'Correction workspaces: %s' % (', '.join(corr.getNames()))

Output:

Correction workspaces: corr_ass, corr_assc, corr_acsc, corr_acc

Categories: Algorithms | Workflow\MIDAS | CorrectionFunctions\AbsorptionCorrections