Reflectometry Changes

Reflectometry Reduction Interface

ISIS Reflectometry


New features of the ISIS Reflectometry Interface

Automatic reduction

  • New ‘automatic reduction’ functionality has been added for automatically reducing all runs obtained from a given investigation ID.

  • With an investigation ID supplied, clicking Autoreduce searches for runs that are included in the investigation, transfers them to the processing table and processes all runs.

  • Automatic reduction can be paused using the new Pause button. It can be resumed by pressing the Autoreduce button again. This will continue the automatic reduction from the last processed row.

  • Changing the instrument, investigation ID or transfer method while paused means that automatic reduction cannot continue where it left off. Therefore, clicking the Autoreduce button again will start a new automatic reduction based on the new settings.

Pausing and resuming reduction

  • A new Pause button has been added which allows pausing of any reduction, whether started using the Process or Autoreduce button.

  • The Process and Autoreduce buttons are greyed out while a reduction is in progress. They are enabled again when the reduction is paused so that they can be used to resume the reduction.

  • When the Pause button is clicked, the reduction might not stop immediately, but will stop as soon as the current row has finished processing. This ensures that nothing is left in a partially-completed state.

  • If the row selection is changed while a reduction is paused, the newly-selected rows will be processed instead of the original rows when the Process button is clicked. However, the row selection is irrelevant when using Autoreduce, because this will continue from the last-processed row.

  • The interface cannot be closed while a reduction is in progress. Therefore, the Pause button can be used to stop data reduction so that the interface can be closed.

  • Data and settings should not be edited while a reduction is in progress. Pausing reduction allows changes to be safely made:

    • Rows and groups may be edited while a reduction is paused. They will be marked as ‘unprocessed’ so that they are re-processed when the reduction is resumed.

    • Altering data within a row will mean that its containing group will also be re-processed.

    • Adding/removing rows from a group will mean that the group will be re-processed.

    • Deleting or renaming output workspaces of processed rows/groups will mean that that row/group will be re-processed.

Other changes

  • Rows and groups that have been successfully processed are highlighted green:

    • Rows are highlighted when reduction has completed.

    • Groups are highlighted when post-processing has completed. Note that if a group does not have any applicable post-processing then it will never be highlighted, even if all of its child rows are highlighted.

  • The interface now operates asynchronously, so that one can still interact with the rest of MantidPlot while data is processing (instead of freezing MantidPlot until processing has finished).

  • The calculation of \(\frac{dQ}{Q}\) has been fixed in line with the changes to the NRCalculateSlitResolution v1 algorithm detailed below. An additional bug has been fixed where the interface was passing \(\theta\) to this algorithm instead of \(2\theta\).

ISIS Reflectometry (Old)

  • The calculation of \(\frac{dQ}{Q}\) has been fixed in line with the changes to the NRCalculateSlitResolution v1 algorithm. An additional bug has been fixed where the interface was passing \(\theta\) to this algorithm instead of \(2\theta\).


  • The following bugs have been fixed in the summation in Q functionality in ReflectometryReductionOne v2:

    • the incorrect angle was being used in the final conversion to Q in the divergent beam case

    • the input was being cropped, causing loss of counts

    • summation in Q was giving incorrect results for a point detector

  • The following new properties have been added to ReflectometryReductionOneAuto v3:

    • ThetaLogName: allows you to specify the name of a log value to use for theta.

    • CorrectDetectors: specifies whether detector positions should be corrected when ThetaIn or ThetaLogName is provided. If true (default), detectors will be moved to the specified theta using SpecularReflectionPositionCorrect v2. Otherwise, theta will still be overridden but without detector positions being changed.

    • Diagnostics: enable the output of additional interim workspaces for debug/validation.

  • A new version of SpecularReflectionCalculateTheta (version 2) has been added which works with detectors at \(2\theta\), in line with ReflectometryReductionOneAuto v3. Version 1 works with detectors at \(\theta\). Note that ReflectometryReductionOneAuto v3 has been adjusted so that its output is not affected.

  • The following changes have been made to CalculateResolution:

    • The algorithm has been renamed to NRCalculateSlitResolution v1 as this algorithm is specific to neutron reflectometry, and the resolution it calculates is the slit resolution.

    • Some errors in the resolution calculation have been fixed. Note that this affects the Q binning in the results of ReflectometryReductonOneAuto (versions 1 and 2) and ReflectometryReductionOne (version 1 only).

    • The TwoThetaLogName property has been replaced by ThetaLogName. This still takes Theta as the default log name. This was causing confusion because it was being used as two theta; it is now being used as theta, as the new property name suggests.

    • The output property TwoThetaOut has been removed because it is not useful. The algorithm now returns a single value which is the resolution.

  • LoadILLReflectometry v1 has been fixed to correctly load D17 files acquired in the TOF mode.

Full list of changes on github