Ticket #9448 (closed: fixed)
Representation of source spectrum for POLDI
| Reported by: | Michael Wedel | Owned by: | Michael Wedel |
|---|---|---|---|
| Priority: | major | Milestone: | Release 3.2 |
| Component: | Diffraction | Keywords: | POLDI |
| Cc: | Blocked By: | ||
| Blocking: | #9445 | Tester: | Roman Tolchenov |
Description
Some of the POLDI routines need knowledge of the spectrum of the incoming neutron beam for intensity calculations. This spectrum is maintained as a list of Wavelength/Intensity-pairs with the condition that the average intensity is 1.
The spectrum was determined experimentally and should go into the IDF.
Attachments
Change History
Changed 6 years ago by Michael Wedel
- Attachment example_spectrum.xml added
Wavelength distribution of POLDI source
comment:2 Changed 6 years ago by Michael Wedel
For calculating the full 2D-spectrum of a POLDI experiment given a set of lattice spacings, the wavelength distribution of the neutrons coming from the source must be known. This is required for calculating the intensities. In the current software, the intensity is interpolated from a lookup table which is determined experimentally.
To make this accessible, I wrote a small wrapper class some time ago, essentially wrapping Mantid::Kernel::Interpolation. It extracts the spectrum from an Instrument and exposes the value()-method of Interpolation. I think it's useful to have this wrapper in order to provide some semantic information in the code using it, since the interpolation is just the method that is used internally - the code that needs the spectrum information should not know or care about that.
I can push the changes, since they are already there, so you can have a look.
comment:3 Changed 6 years ago by Michael Wedel
Refs #9448. Added PoldiSourceSpectrum class
A small wrapper class that extracts the wavelength distribution from the source component present in a POLDI instrument.
Changeset: cc53094d2d75c1318a8393da50244a3a0e67bf12
comment:4 Changed 6 years ago by Owen Arnold
I just worried that this would involve core changes outside to this package. Seems fine. On a separate, but related note. If things added to the SINQ package are generally useful, please do propose that they are moved into the (more) core layers.
Reset this ticket to 'clarify' and I will mark it as 'assigned'.
comment:7 Changed 6 years ago by Michael Wedel
- Status changed from assigned to inprogress
Refs #9448. Improved unit tests for PoldiSourceSpectrum
Changeset: 53224a25987ac9c2638bafe84df4ba9366d166e4
comment:8 Changed 6 years ago by Michael Wedel
- Status changed from inprogress to verify
- Resolution set to fixed
Testing info: There is not really anything specific to test, since the class is not used anywhere in the other code yet. A unit test is available.
comment:10 Changed 6 years ago by Roman Tolchenov
- Status changed from verify to verifying
- Tester set to Roman Tolchenov
comment:11 Changed 6 years ago by Roman Tolchenov
Merge remote-tracking branch 'origin/feature/9448_representation_of_poldi_source_spectrum'
Conflicts:
Code/Mantid/Framework/SINQ/CMakeLists.txt Code/Mantid/Framework/SINQ/inc/MantidSINQ/PoldiUtilities/PoldiMockInstrumentHelpers.h
Re #9448
Changeset: 15c57eb1669c6793841eabb4b9fac8fa4272ee08
comment:12 Changed 6 years ago by Roman Tolchenov
- Status changed from verifying to closed
Merge remote-tracking branch 'origin/feature/9448_representation_of_poldi_source_spectrum'
Conflicts:
Code/Mantid/Framework/SINQ/CMakeLists.txt Code/Mantid/Framework/SINQ/inc/MantidSINQ/PoldiUtilities/PoldiMockInstrumentHelpers.h
Re #9448
Full changeset: 15c57eb1669c6793841eabb4b9fac8fa4272ee08
comment:13 Changed 5 years ago by Stuart Campbell
This ticket has been transferred to github issue 10291
Not sure what the scope of the changes relating to this ticket would be. Could you clarify what you intend to change please.