Diffraction Changes

Powder Diffraction

New features

  • Implement minimum range limit for PDFFourierTransform v2 algorithm, e.g. Rmin for Direction="Forward" and Qmin for Direction="Backward".

  • StitchByBackground v1 has been added, which allows for multiple workspaces with different bin widths to be stitched together.

  • A GroupingWorkspace can now be provided to AlignAndFocusPowderSlim to define what detectors go to which output spectra.

  • HFIR MIDAS instrument definition added

  • Support Pawley refinement of TOF workspaces in PawleyPattern1D class and added TOF peak profile BackToBackGauss for back-to-back exponential convoluted with a Gaussian.

  • Support zero shift and scale factor for reflection d-spacings in PawleyPattern1D class (equivalent to modifying TZERO and DIFC).

  • Now when using the spliiter workspace with AlignAndFocusPowderSlim it will output multiple workspaces, one for each target. The SplitterTarget property has been removed.

  • AlignAndFocusPowderSlim is no longer hard-coded for the VULCAN instrument.

Bugfixes

  • Add force_high_q_to_1 option to POLARIS create_total_scattering_pdf to work around a normalisation bug

  • Disabled StripVanadiumPeaks in ref:SNSPowderReduction <algm-SNSPowderReduction>’s test, “SNSPowderRedux.PG3Analysis” because it was causing stochastic test failures on ornl runners and contributed little to the test’s purpose.

  • Solve the crash issue in ref:SNSPowderReduction <algm-SNSPowderReduction> regarding the definition of non-standard sample and container geometries for the absorption correction purpose.

Engineering Diffraction

New features

  • Vanadium normalisation can now be performed during calibration in the Engineering Diffraction interface.

  • In CreatePoleFigureTableWorkspace v1, two new options have been added to the inputs. SpectraWorkspace allows the user to provide a name for a new output workspace which contains spectra corresponding to rows in the standard OutputWorkspace table. IncludeSpectrumInfo is a flag which adds information columns to the final OutputWorkspace about where each spectra has come from.

  • texture_helper.py has been created to hold stand alone texture functionality which is independent of specific instrument workflows or workflow classes.

  • show_texture_sample_shape in texture_helper.py is a new standalone function which allows the user to show the sample present on a workspace along with the texture sample directions, and optionally a gauge volume.

  • load_all_orientations in texture_helper.py is a new standalone function which allows the user to take a sequence of workspaces and apply sample orientations, loaded from an input file (as described in the orientation file section of the Texture Analysis Concept doc)

  • create_pole_figure_tables in texture_helper.py is a new standalone function which allows the user to directly create a single pole figure table for a sequence of workspaces and their fit parameters.

  • plot_pole_figure in texture_helper.py is a new standalone function which allows the user to directly create a pole figure plot for a pole figure table.

  • Pole Figure plots can now be created from texture_helper functions with a debug flag which allows interactive annotation of points in the pole figure by holding “a” key on the keyboard and clicking.

  • Added calibrated IDF for POLDI (PSI) post upgrade in December 2025

  • New loader load_poldi_h5f for h5f file produced by POLDI post instrument upgrade in plugins.algorithms.poldi_utils

  • New features in PoldiAutoCorrelation v6

    • Add parameter NGroups` to split POLDI detectors into groups and produce a autocorrelation spectrum per grouping

    • Associate detector IDs with autocorrelation spectra in output workspace

  • New features in PawleyPattern1D class in Engineering.pawley_utils

    • Method to perform ‘free’ fit - i.e. do not constrain peak centres to predicted positions

    • Improvements to robustness of background estimation

    • Method to fit background function to 1D data using a cost function that is biased to be less sensitive to positive outliers.

  • Added class PawleyPattern2DNoConstraints in Engineering.pawley_utils to do a ‘free’ 2D refinement of POLDI data

  • Update to the Engineering Diffraction interface, adding two tabs, Absorption Correction and Texture.

  • The new Absorption Correction tab allows the user to correct workspaces for the beam attenuation through the sample.

  • The new Texture tab allows the user to combine data from focused workspaces and peak fitting, to plot pole figures for their experimental data

  • Basic usage of these tabs as part of a texture analysis reduction pipeline has been documented in the Texture Technique Documentation

  • Use multi-threading in EnggEstimateFocussedBackground v1 algorithm to speed up execution time by factor ~2-3

Bugfixes

Single Crystal Diffraction

New features

  • HFIR IMAGINE instrument image plate instrument definition detector add to instruments

  • Added new instrument IMAGINE-X

Bugfixes

  • ConvertQtoHKLMDHisto is faster by removing unnecessary copy

  • Verified and corrected IMAGINE-X detector layout using neutron absorbing masks.

Release 6.15.0