Diffraction Changes#

Powder Diffraction#

POLARIS now provides sensible starting parameters for Back2BackExponential
AlignAndFocusPowderSlim v1 now accepts a CalibrationWorkspace and a MaskWorkspace. When supplied, these take precedence over the corresponding information in CalFileName. AlignAndFocusPowderFromFiles v1 has been updated to pass these parameters to AlignAndFocusPowderSlim v1.

CylinderAbsorptionCW now scales the AttenuationXSection property from its tabulated 1.7982 Å value to the requested Wavelength. Previously cross-sections provided through the properties were used unscaled, so they gave a different result to the same cross-sections set on the sample material with SetSampleMaterial v1 at any wavelength other than 1.7982 Å.
ISIS Powder SampleDetails now accepts a number_density_units argument which can be set appropriately to fix issues where total scattering S(Q)-1 does not tend to 0 at high Q when number density has been provided as: formula units per volume (see number_density_unit).
Fixed the binning of HFIRPowderReduction v1. The bins are now placed on a grid of XBinWidth anchored at XMin, or at zero when XMin is not given, so bin centres always fall on XMin + XBinWidth * (n + 1/2). Previously a XMin (or XMax) outside the range of the data was replaced by the extreme value found in the data, which shifted every bin and made the bins slightly wider than XBinWidth. XMin and XMax are now both optional and take a single number rather than a list of per-spectrum values, and only the bins that hold data are output.
Fixed HFIRPowderReduction v1 producing incorrect results when SampleBackgroundFilename was supplied. The sample background was subtracted without being normalised to monitor or time, and SampleBackgroundScaleFactor was ignored.
Fixed CylinderAbsorptionCW Sabine calculation for large μR

The obsolete properties UnwrapRef, LowResRef and LowResSpectrumOffset have been removed from AlignAndFocusPowder, AlignAndFocusPowderFromFiles and SNSPowderReduction.

New Texture Planning User Interface for aiding the user in planning and executing Texture Analysis experiments. See the linked docs for more information.
In Engineering Diffraction interface the settings now supports saving experiment specific settings, based on RB Number. Previous behaviour was that every time a setting was changed it would overwrite the previous saved version of the setting, where as now, it will overwrite the previous version saved for that RB Number. This allows users to return to experiments and find have specific settings have been remembered.
In Engineering.EnggUtils, focusing using the focus_run method will now adjust the calibration DIFCs per detector pixel to account for an offset in the scattering volume centre-of-mass (due to sample partially illuminated within the gauge volume). This is only done when both a Sample Shape and Gauge Volume are present on the Workspace.
In Engineering Diffraction interface the GSASII tab now supports CIF file selection from a list of defaults distributed with Mantid.

HB3AAdjustSampleNorm v1 can now output an unnormalized Q-sample event workspace and a separate normalization workspace for use with MDNorm v1.
SCDCalibratePanels has a new WavelengthFromUB option to derive each peak’s wavelength from Bragg’s law using the UB matrix and its integer HKL instead of from the measured TOF. This is intended for quasi-Laue workflows, where a peak’s TOF-derived wavelength can be unreliable, but it also works for standard time-of-flight Laue data.
On WISH the Back2BackExponential starting parameter values have been updated post upgrade, late 2025
Added the FindUBFromConventionalCell algorithm, which determines a UB matrix (crystal orientation) from unindexed peaks and the known conventional-cell lattice parameters and centering.
MDNorm can now normalize monochromatic single crystal diffraction data (e.g. WAND, DEMAND) using a pre-computed normalization workspace, via the new MonoSCDNormalizationWorkspace property.

SaveIsawDetCal v1 and SaveIsawPeaks v1 now record the calibrated positions of CORELLI detector panels. Since Mantid 6.15.0.1 they wrote the nominal positions taken from the instrument definition, so a panel calibration was silently absent from the .DetCal and .peaks files they produced. SaveIsawPeaks v1 also wrote nominal panel orientations and sizes, which affected WISH as well as CORELLI. CORELLI and WISH files written with an affected version should be regenerated.
SaveHKL v1 and AnvredCorrection v1 now use the calibrated detector distance in the slant-path absorption correction for CORELLI, having used the nominal distance since Mantid 6.15.0.1.
Fixed the Counts vanadium normalization option in LoadWANDSCD v1 so detector counts are scaled by the mean vanadium signal when applying the vanadium correction.