6.4

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ExtractPolarizationEfficiencies v1

../_images/ExtractPolarizationEfficiencies-v1_dlg.png

ExtractPolarizationEfficiencies dialog.

Summary

Extracts polarization efficiencies from instrument’s parameter file.

Properties

Name Direction Type Default Description
InputWorkspace Input MatrixWorkspace Mandatory A workspace with attached instrument whose parameters contain polarization efficiencies.
OutputWorkspace Output MatrixWorkspace Mandatory The workspace with extracted efficiencies.
CorrectionMethod Output string   Correction method: Fredrikze or Wildes.
CorrectionOption Output string   Correction option, eg “PA” or “PNR” for Fredrikze method.

Description

This algorithm reads polarization correction parameters from the instruments parameters file and creates an efficiency workspace ready to be used with PolarizationEfficiencyCor v1. It is intended to be used as a child algorithm by the reflectometry reduction algorithms and not to be used directly.

To work with this algorithm the parameters file must contain the following parameters (all of type string and in the scope of the instrument):

  1. polarization_correction_method to specify the method of correction. Possible values are Fredrikze and Wildes.
  2. polarization_correction_option to specify the additional property of the correction algorithm. For Fredrikze the possible values are those of the PolarizationAnalysis property. For Wildes they are the values of the Flippers property.
  3. efficiency_lambda is a vector of wavelengths at which the efficiencies are sampled.
  4. A set of four parameters for each of the four efficiencies stored as vectors of values at the wavelengths in efficiency_lambda. The names of the parameters are different for the two methods of correction: Pp, Ap, Rho and Alpha for Fredrikze and P1, P2, F1 and F2 for Wildes.

The values in the vector parameters must be separated by spaces, for example:

<parameter name="efficiency_lambda" type="string">
  <value val="0 1 2 3 4 5" />
</parameter>

Categories: AlgorithmIndex | DataHandling | Reflectometry\ISIS