Calculate Flat background removes backgound from monitors.

[Alex Buts]

This should never happens.

The script below provides workspace 2 match either when calculateFlatBackground is disabled or when one explicitly provides the list of the spectra, which excludes monitors. This actually means that it removes background from monitors which is useless operation and dangerous operation. Instrument scientists were complaining to me about strange behaviour of the background removal, but I did not understood the reason behind this.

Should be fixed.

######################################################################
#Python Script Generated by GeneratePythonScript Algorithm
######################################################################
Load(Filename=r'd:\Data\MantidSystemTests\Data\MAR11001.raw',OutputWorkspace='MAR11001.raw')
LoadDetectorInfo(Workspace='MAR11001.raw',DataFilename=r'd:\Data\MantidSystemTests\Data\MAR11060.raw',RelocateDets='1')

GetEi(InputWorkspace='MAR11001.raw',Monitor1Spec='2',Monitor2Spec='3',EnergyEstimate='12')
ScaleX(InputWorkspace='MAR11001.raw',OutputWorkspace='11001.spe',Factor='-6536.707778516824',Operation='Add',InstrumentParameter='DelayTime',Combine='1')
MoveInstrumentComponent(Workspace='11001.spe',ComponentName='Moderator',Z='-1.4419999999999999',RelativePosition='0')

ConvertToDistribution(Workspace='11001.spe')
spectra=range(3,921);
CalculateFlatBackground(InputWorkspace='11001.spe',OutputWorkspace='11001.spe',WorkspaceIndexList=spectra,StartX='11463.292221483176',EndX='12963.292221483176',Mode='Mean')
ConvertFromDistribution(Workspace='11001.spe')
#
CropWorkspace(InputWorkspace='11001.spe',OutputWorkspace='11001_OldCFine.spe',StartWorkspaceIndex='3',EndWorkspaceIndex='921')
#
NormaliseToMonitor(InputWorkspace='11001.spe',OutputWorkspace='11001.spe',MonitorSpectrum='1',IntegrationRangeMin='-5536.7077785199999',IntegrationRangeMax='-4536.7077785199999',IncludePartialBins='1')
CropWorkspace(InputWorkspace='11001.spe',OutputWorkspace='11001_step1aOldC.spe',StartWorkspaceIndex='3',EndWorkspaceIndex='921')
############################################################################################################

######################################################################
#Python Script Generated by GeneratePythonScript Algorithm
######################################################################
Load(Filename=r'd:\Data\MantidSystemTests\Data\MAR11001.raw',OutputWorkspace='MAR11001.raw',LoadMonitors='Separate')
LoadDetectorInfo(Workspace='MAR11001.raw',DataFilename=r'd:\Data\MantidSystemTests\Data\MAR11060.raw',RelocateDets='1')

GetEi(InputWorkspace='MAR11001.raw_Monitors',Monitor1Spec='2',Monitor2Spec='3',EnergyEstimate='12')
AddSampleLog(Workspace='MAR11001.raw',LogName='Ei',LogText='12.9728953307',LogType='Number')
ScaleX(InputWorkspace='MAR11001.raw_Monitors',OutputWorkspace='11001.spe_monitors',Factor='-6536.707778516824',Operation='Add',InstrumentParameter='DelayTime',Combine='1')
ScaleX(InputWorkspace='MAR11001.raw',OutputWorkspace='11001.spe',Factor='-6536.707778516824',Operation='Add',InstrumentParameter='DelayTime',Combine='1')
MoveInstrumentComponent(Workspace='11001.spe',ComponentName='Moderator',Z='-1.4419999999999999',RelativePosition='0')
#
ConvertToDistribution(Workspace='11001.spe')
CalculateFlatBackground(InputWorkspace='11001.spe',OutputWorkspace='11001.spe',StartX='11463.292221483176',EndX='12963.292221483176',Mode='Mean')
ConvertFromDistribution(Workspace='11001.spe')
#
CloneWorkspace(InputWorkspace='11001.spe',OutputWorkspace='11001NewFine')

rez=CheckWorkspacesMatch('11001NewFine','11001_OldCFine.spe');
print ' Match1=',rez

# Causes difference:
NormaliseToMonitor(InputWorkspace='11001.spe',OutputWorkspace='11001.spe',MonitorWorkspace='11001.spe_monitors',IntegrationRangeMin='-5536.7077785199999',IntegrationRangeMax='-4536.7077785199999',IncludePartialBins='1')
#AddSampleLog(Workspace='11001.spe',LogName='DirectInelasticReductionNormalisedBy',LogText='monitor-1')


rez=CheckWorkspacesMatch('11001_step1aOldC.spe','11001.spe');
print ' Match2=',rez

[Owen Arnold]

I can see why this option might be desired, but these changes should also be discussed with Tim Charlton and Max Skoda if your solution involves changing the default behaviour of CalculateFlatBackground to make it ignore monitors because one of the scripts they provided to me:

​https://github.com/mantidproject/mantid/blob/82fd32291923748ce439f3d388a81785ec0524fa/Code/Mantid/scripts/Reflectometry/isis_reflectometry/quick.py#L384

includes CalculateFlatBackground on monitor spectrum.

[Alex Buts]

refs #9312 Added option to skip background removal from monitors.

Changeset: e0bcbd8ae9d3c702e21444207131d64e13828eac

[Alex Buts]

refs #9312 Added unit test for the option

Changeset: 236174765e5d22ec1d334b3da72c911c1955fb63

[Alex Buts]

refs #9312 Minor comments.

Changeset: fdba0c0425b961bcc0231dc1686f4dc999e17298

[Alex Buts]

The script above is an overkill to test this ticket.

As apparently some people do want to remove background from monitors (not an inelastic one), I've introduced new algorithm parameter which prohibit this but the background from monitors is still removed by default.

Changes are trivial, unit test for this written and works so it is easy to test this ticket by code review.

[Alex Buts]

refs #9312 Add some Comments

Changeset: 2f99de646b372624bf409f6425086ec2ec50743d

[Alex Buts]

refs #9312 Logging if no detector found.

Changeset: 12626c712fdaa43f8c728aa7f4b4d63a583e9e7f

[Karl Palmen]

Merge remote-tracking branch 'origin/bugfix/9312_backgroundNoMonitors'

Full changeset: ​21d4d2d4b1c947f0fdae8885ad1f5672aafaface

[Alex Buts]

Merge branch 'bugfix/9312_backgroundNoMonitors' into bugfix/9135_ISISRawAndMonitors

Full changeset: ​cc89ee70b106ca72f986fc64d7ef17183f088343

[Alex Buts]

Merge branch 'bugfix/9312_backgroundNoMonitors' into bugfix/9135_ISISRawAndMonitors

Full changeset: ​b441bfcaf08758b4b1075d2f1e8c0afd24a8b72b

[Stuart Campbell]

This ticket has been transferred to github issue ​10155