Background and monitors issue in SANS reduction

[Gesner Passos]

It was firs noticed by Sarah who asked the difference between these two commands:

BACK/M1/TIMES 35000 98000 BACK/M1 35000 98000

It turned out that we have two bugs. First, we do not recognize this syntax:

BACK/M1/TIMES but BACK/M1/TIME

And second, we use for the normalization 'NormalizeToMonitor' always the monitor 1 despite of the monitor chosen for the transmission.

[Gesner Passos]

I checked for how long this issue has been around, and it turned out that it was born in this way - 2011.

​https://github.com/mantidproject/mantid/commit/d40a7fe88a2f79d2de2e7c1c6ce03745cf0bd176 ​https://github.com/mantidproject/mantid/commit/4ef639235d778ba90a9c93dd39451529da2d0477

[Gesner Passos]

To reproduce the problem issue:

• Open ISIS interface
• Load the mask.txt file
• Change to Batch mode and load systemtests/Data/SANS2D/sans2d_reduction_gui_batch.csv
• Execute Reduction
• Execute the check_alg_mon -> you must see ExtractSingleSpectrum, Index=0 and CalculateFlatBackground limits 35000, 65000.
• Open the file mask.txt and check that these are the limits for the monitor 1.
• Change in the Reduction Settings the Incident Monitors for Scattering to 2.
• Execute Reduction
• Execute the check_alg_mon -> you will see ExtractSingleSpectrum, Index=1 and CalculateFlatBackground limits 35000, 65000.
• But the limits for the monitor 2 inside the mask.txt is 85000 98000 !

[Gesner Passos]

Besides,

substitute BACK/M1 line from mask.txt to BACK/M1/TIMES 35000 65000.

Run execute Reduce and after the check_alg_mon. No CalculateFlatBackground appear!

[Gesner Passos]

re #8753: Remove the background from the used monitor

Correct a bug found that only monitor 1 was being used. But, it ought to use the monitor defined inside the mask file.

As a minor thing, remove the sans_reduction_steps.Normalize inheritance, because it was not adding anything for this class.

Changeset: b0463eaeb8e266f7d71f171b816c18b0cda7729d

[Gesner Passos]

re #8753: Correct the misspelling of the back syntax

Changeset: 3546a3c389b7c0f73c25a0677b3823b3f1ffa4ab

[Gesner Passos]

re #8753: Add unit test for back syntax

Changeset: 382af86550c8915da83970e27f48b10c85ccd8ad

[Gesner Passos]

re #8753: Update the data after fixing the bug on back syntax

The difference is small, and refers only to the new range applied to the monitors inside the algorithm CalculateFlatBackground

You can check this by comparing the history.

Changeset: da38f186bed454fb9649d94f4876cf2c6a8a183d

[Gesner Passos]

Revert "re #8753: Update the data after fixing the bug on back syntax"

This reverts commit da38f186bed454fb9649d94f4876cf2c6a8a183d.

Changeset: ae7bcef86900a3db8e50fbad4d9fb911cb057078

[Gesner Passos]

re #8753: Translation of the mask file to the proper syntax

Changeset: 5ccee1ff7af8e4cc476e174e5cf08bbd665ab889

[Gesner Passos]

re #8753: update of the data to adapt to the bugfix

Changeset: 32662ba0faaf60d9c3ce9a3e42ed72a868b5769a

[Gesner Passos]

Tester:

Go through the steps to reproduce the issue and check that it is sorted out.

[Samuel Jackson]

Tested that I could reproduce the problem, then followed the testing information. Both issues appear to be solved and the code changes look good.

[Samuel Jackson]

Merge remote-tracking branch 'origin/bugfix/8753_back_syntax'

Full changeset: ​bb0bafd8f431de8d341dfb8de3b0e941a88286cc

[Gesner Passos]

Merge remote-tracking branch 'origin/bugfix/8753_back_syntax'

Full changeset: ​3e163fafde379ff13413e705837dea20fb3edc55

[Stuart Campbell]

This ticket has been transferred to github issue ​9597