indirect_inelastic.rst

Indirect Inelastic Changes

Table of Contents

• Algorithms
  • New
  • Improved
  • Bugfixes
• Indirect Interfaces
• Vesuvio
• General
  • Dropped
  • Bugfixes

Algorithms

New

• :ref:`SimpleShapeMonteCarloAbsorption <algm-SimpleShapeMonteCarloAbsorption>` has been added to simplify sample environment inputs for MonteCarloAbsorption.
• :ref:`algm-CalculateMonteCarloAbsorption` calculates Paalman Pings absorption factors from a sample and container workspace, given shape specific input.

Improved

• The following changes were made to the :ref:`algm-MSDFit` algorithm:

  • Added model selection to the :ref:`algm-MSDFit` algorithm, with three current models: :ref:`MsdGauss <func-MsdGauss>`, :ref:`MsdYi <func-MsdYi>`, and :ref:`MsdYi <func-MsdYi>`. New models now work with workspaces in Q not Q^2 (e.g. _eq workspaces 'Elastic Q').

• The following changes were made to the the :ref:`algm-ConvolutionFitSequential` algorithm:

  • Added 'ExtractMembers' property to :ref:`algm-ConvolutionFitSequential` - this allows for extracting the members of the convolution fitting into their own workspaces.
  • Property to pass the workspace index added to :ref:`algm-ConvolutionFitSequential`.
  • The :ref:`algm-ConvolutionFitSequential` now performs correct treatment of the resolution function: convolve sample and resolution spectra with same momentum transfer.

• The following changes were made to the the :ref:`algm-ISISIndirectDiffractionReduction` algorithm:

  • Manual D-Ranges can now be supplied as a list/range, to the :ref:`algm-ISISIndirectDiffractionReduction` algorithm, each corresponding to their respective runs, in the supplied order.
  • The Sum Files option in the :ref:`algm-ISISIndirectDiffractionReduction` algorithm now allows for correctly corresponding each sum of sample runs defined with a range (e.g. A-B, where A and B are run numbers) to the corresponding vanadium run, dependent on D-Range.
  • The 'Sample Runs' field in the :ref:`algm-ISISIndirectDiffractionReduction` algorithm now recognizes 3 operators: '-', '+', ':'. The '-' operator is used to supply a given range of runs and sum them when SumFiles is checked. The '+' operator is used to supply a given list of runs and sum when SumFiles is checked. The ':' operator is used to supply a range of runs, which will never be summed.
  • The Grouping Policy in :ref:`algm-ISISIndirectDiffractionReduction`, now allows for grouping with a Workspace.

• :ref:`FlatPlatePaalmanPingsCorrection <algm-FlatPlatePaalmanPingsCorrection>` now supports Direct and Indirect modes.
• :ref:`BASISReduction <algm-BASISReduction>` can save to NXSPE format.

Bugfixes

• :ref:`algm-ElasticWindowMultiple` now correctly normalizes by the lowest temperature - rather than the first one.
• An issue has been fixed in :ref:`algm-IndirectILLEnergyTransfer` when handling the data with mirror sense, that have shifted 0 monitor counts in the left and right wings. This was causing the left and right workspaces to have different x-axis binning and to fail to sum during the unmirroring step.
• An issue has been fixed in :ref:`algm-IndirectILLReductionFWS` when the scaling of the data after vanadium calibration was not applied.
• :ref:`algm-CalculateSampleTransmission` now divides by the tabulated wavelength when calculating the absorption cross section.

Indirect Interfaces

• The Indirect Absorption Corrections interface has been replaced with Calculate Monte Carlo Absorption Corrections; using the new :ref:`algm-CalculateMonteCarloAbsorption` algorithm.
• In the Indirect ConvFit interface, EISF is now extracted as a parameter when performing a single fit using 'Fit Single Spectrum'.
• The Indirect S(Q, W) interface now automatically replaces NaN values with 0.
• The Save Result option in the Indirect Elwin interface now writes to file the temperature-dependent elastic intensity normalized to the lowest temperature.
• Model selection is available in the Indirect MSDFit interface, providing the option to choose one of the three models available in the :ref:`algm-MSDFit` algorithm.
• Removed fit option from plot options drop-down menu, in the Indirect Bayes interface.
• Use Manual Grouping in the Indirect Diffraction interface now functions in the same way as the equivalent option in the Indirect ISISEnergyTransfer interface; providing and option to choose the number of groups and subsequently grouping by detector.
• Plot Current Preview is now an available option across all Indirect interfaces, where a mini-plot is shown within the interface.

Vesuvio

• Added flag for disabling multiple scattering corrections: flags['ms_flags']['ms_enabled'].
• Added method for specifying a mass by chemical symbol e.g. H for hydrogen, O for oxygen.
• Multiple scattering corrections for back-scattering spectra now approximate the hydrogen peak, this is done in the :ref:`algm-VesuvioCorrections` algorithm. This feature is incomplete for 3.11.
• :ref:`algm-VesuvioCorrections` has the additional property: 'MassIndexToSymbolMap'. MassIndexToSymbolMap is used to map from an index of mass in the 'Masses' property to a chemical symbol.
• :ref:`algm-VesuvioCorrections` takes the additional property: 'HydrogenConstraints'. HydrogenConstraints are used to constrain the hydrogen peak for multiple scattering corrections in back-scattering spectra.
• Gamma Corrections are no longer done for back-scattering spectra in the :ref:`algm-VesuvioCorrections` algorithm.

General

Dropped

• LoadILLIndirect-v1, IndirectILLReduction, ILLIN16BCalibration algorithms deprecated since v3.9, are now removed.

Bugfixes

• A number of Python indirect algorithms that use :py:obj:`mantid.kernel.MaterialBuilder` allowed setting the mass density for a material. The density was set incorrectly where the chemical formula had more than one atom, this is now fixed.

Full list of changes on GitHub