Diffraction Changes#

Powder Diffraction#

New features#

Bugfixes#

  • When loading POLDI data recorded from December 2025 onwards, the chopper calibration constants t0 and t0_const can now be taken from a instrument parameter file.

  • The current POLDI instrument definition file has been renamed from POLDI_Definition_896.xml to POLDI_Definition.xml. Scripts that load this file by name need updating; loading POLDI data by instrument name or run date is unaffected.

Engineering Diffraction#

New features#

  • In the Texture Experiment Planner, when exporting a reference workspace with Save Euler Settings on Reference ticked, the orientation file Axes and Senses from the settings menu are now saved onto the reference workspace.

  • In the Absorption Correction tab of the Engineering Diffraction interface, when loading a reference workspace that carries saved Euler settings, the Euler Angle Scheme and Euler Angles Sense settings for the current RB number are now replaced with the saved ones. Untick Read Euler settings from a loaded reference workspace in the settings to keep your own.

  • The POLDI 2D Pawley refinement classes (PawleyPattern2D, PawleyPattern2DNoConstraints) have moved from Engineering.pawley_utils to Engineering.poldi_pawley_utils; scripts importing them must update the import. Engineering.pawley_utils keeps the instrument-agnostic classes (e.g. Phase, PawleyPattern1D).

  • In the Texture Experiment Planner, a new help button on the bottom toolbar opens the documentation for the interface.

Bugfixes#

Single Crystal Diffraction#

New features#

  • ConvertHFIRSCDtoMDE v1 now accepts a WorkspaceGroup of detector-space workspaces, such as several HB3A scans from HB3AAdjustSampleNorm v1 with OutputType="Detector". Each scan is converted with its own goniometer settings and wavelength. The result is a WorkspaceGroup named as in HB3AAdjustSampleNorm v1, or, with the new MergeInputs property, a single merged MDEventWorkspace.

  • ConvertHFIRSCDtoMDE v1 now uses the wavelength sample log of the input workspace when present, as HB3AAdjustSampleNorm v1 does, and the Wavelength property only when the log is missing; a warning is logged when the two values differ. Previously the Wavelength property was always used. Wavelength can now hold one value per member of a WorkspaceGroup.

  • New algorithm HFIRSCDSubtractBackground v1 subtracts a background measured at a single goniometer angle from WAND and DEMAND data in detector space, before the conversion to Q-sample. The background is scaled to the time or monitor counts of each goniometer angle of the sample, and the uncertainties are propagated. The sample can be a WorkspaceGroup of scans, the subtraction can be done in place to save memory, and an ungrouped background can be grouped to match a sample loaded with pixel grouping.

  • LoadWANDSCD v1 now returns raw counts by default: NormalizeData defaults to False instead of True. Scripts that provide vanadium data and rely on the previous default to normalize the data must now set NormalizeData=True. The algorithm also rejects inputs where the vanadium data would be missing or unused: NormalizeData=True or OutputNormalizationWorkspace without vanadium data, and vanadium data with NormalizeData=False and no OutputNormalizationWorkspace. Previously these inputs were accepted, and the vanadium data or the normalization request was ignored.

  • MDNorm v1 now rejects BackgroundWorkspace for monochromatic single crystal diffraction, that is, when MonoSCDNormalizationWorkspace is given or InputWorkspace comes from WAND or DEMAND, with a message that refers to HFIRSCDSubtractBackground v1. The background of WAND and DEMAND data is to be subtracted in detector space, before the conversion to Q-sample with ConvertHFIRSCDtoMDE v1.

Bugfixes#

Release 7.1.0