diffraction.rst

Diffraction Changes

Table of Contents

• Crystal Improvements
• Single Crystal Diffraction
• Engineering Diffraction
• Powder Diffraction
• Imaging

Crystal Improvements

Single Crystal Diffraction

• HFIR HB3A's data reduction interface application (MantidPlot/Interfaces/Diffraction/HFIR 4Circle Reduction) has been expanded and improved from previous release. It provides an integrated user-friendly interface for instrument scientists and users to access data, calculate and refine UB matrix, merge multiple data sets for slice-view and peak integration.
• :ref:`IntegratePeaksMDHKL <algm-IntegratePeaksMDHKL>` has been added to integrate data in HKL space. The main usage will be to normalize the data using :ref:`MDNormSCD <algm-MDNormSCD>` and then integrate the resulting MDHistoWorkspace, but it also integrates MDHistoWorkspaces and MDEventWorkspaces without normalizing. The MD data must be in units of HKL. A 3D box is created for each peak and the background and peak data are separated. The intensity and sigma of the intensity is found from the grid inside the peak and the background is subtracted. The boxes are created and integrated in parallel and less memory is required than binning all HKL space at once. The figure shows the grid points within an HKL box that are in one peak from Si data.

• Some improvements were done for creating peaks from python. :ref:`CreatePeaksWorkspace <algm-CreatePeaksWorkspace>` copies the goniometer from the input MatrixWorkspace to PeaksWorkspace. createPeak for PeaksWorkspace copies goniometer from PeaksWorkspace to peak. setGoniometer for a peak can be done from python and setQLabFrame and setQSampleFrame works correctly now with one argument.

Engineering Diffraction

• EnggFocus: bins are now masked at the beginning of the workflow (when using the option MaskBinsXMins)
• :ref:`SaveDiffFittingAscii <algm-SaveDiffFittingAscii>` an algorithm which saves a TableWorkspace containing diffraction fitting results as an ASCII file
• New Fit All button on the Fitting Tab will enable user to batch-process all the runs and banks when a range of run number is given. During the Fit process, :ref:`SaveDiffFittingAscii <algm-SaveDiffFittingAscii>` algorithm will be utilised to save engggui_fitting_fitpeaks_param TableWorkspace as a csv file.
• New Load button on the Fitting Tab, will enable user to load the focused file to the canvas, so that the user can select the peaks manually beforehand

Powder Diffraction

• :ref:`SNSPowderReduction <algm-SNSPowderReduction>` has changed parameters. Instrument, RunNumber, and Extension have been replaced with a single Filename parameter. This has been paired with changes to the Powder Diffraction interface as well. There were also a variety of bugfixes related to the output workspaces. While it did not affect the saved data files, the output workspaces were not always correctly normalized or in the requested units.
• :ref:`PDFFourierTransformSNSPowderReduction <algm-PDFFourierTransformSNSPowderReduction>` has been modified to look at the signal as well when looking at the Q-range to use for the transform.

• :ref:`cry-powder-diffraction-ref`: S-Empty option has been enabled for

  the Crystallography Powder Diffraction Script. In order to use the S-Empty option, simply provide the S-Empty run number within the .pref file.

• :ref:`CorelliCrossCorrelate <algm-CorelliCrossCorrelate>`: The weights applied to events have changed by a factor of the duty cycle (c\approx0.498) as requested by the instrument scientists.
• :ref:`pearl-powder-diffraction-ref`: A workflow diagram for pearl_run_focus function has been created.

Imaging

• An updated version of the IMAT instrument definition now includes prototype diffraction detector banks.

Full list of diffraction and imaging changes on GitHub.