[defect] using erroneous mantid instrument information when generating sensitivity file with legacy data

[glass-ships]

Problem Description:

When generating the sensitivity file the instrument xml in Mantid will be used erroneously.

Steps to Reproduce:

BioSANS_MainSens_XMLtoNXS_Template_Edited.ipynb

When generate the sensitivity file with this notebook script the generated file has different instrument geometry (pixel positions) to the original nexus file. This wrong geometry is imported from the default file in Mantid without confirming with the instrument scientist. This is an issue when the using legacy files for reduction or generating sensitivity files.

Investigation/Analysis Results:

In https://code.ornl.gov/sns-hfir-scse/sans/sans-backend/-/blob/next/drtsans/load.py#L148

If the option LoadNexusInstrumentXML is missing then the code will automatically load the Mantid default instrument xml.

While generating sensitivity correction files, this option is not specified so the nexus instrument xml will be omitted

https://code.ornl.gov/sns-hfir-scse/sans/sans-backend/-/blob/next/drtsans/prepare_sensivities_correction.py#L763

Which produces incompatible detector geometries (pixel positions) in resulting files.

An explicit option has to be added to this function call to enforce to copy the nexus instrument xml

[glass-ships]

This issue was migrated from code.ornl.gov.