Ticket #5105 (closed: fixed)
Custom GetEi algorithm for CNCS
Reported by: | Stuart Campbell | Owned by: | Andrei Savici |
---|---|---|---|
Priority: | major | Milestone: | Release 2.2 |
Component: | Mantid | Keywords: | |
Cc: | reuterma@… | Blocked By: | |
Blocking: | Tester: | Michael Reuter |
Description
from Georg Ehlers:
I have played during the last few days a little bit with CNCS data looking for a way to determine Ei from the data reliably to cross-check the entry "energyrequest" stored in the nxs files. I have found that you need to use the elastic line in the detectors and the spectrum of "monitor3". This is the one mounted onto the backside of the high speed double disk chopper (facing the sample). Even though the two locations are fairly close to each other at the end of the spectrometer, one can seemingly determine Ei accurately from the difference in tof. So, I am OK with you implementing this for the general one-solve-all python reduction script for CNCS. I suggest you restrict the detector counts to equator-near pixels (e.g., pixels 54-73) for banks (modules) 1-30. I suggest you read the module distances from the sample (these locations change frequently) and the monitor location from the nxs file. Further I do suggest that you don't fit the peaks, rather use the center of mass. One can also get T0 accurately enough from this. Do not use monitor2. I found that the spectrum it sees is "too white" and the center of the peak is not close enough to the tof of the desired energy at this location.
Change History
comment:2 Changed 8 years ago by Nick Draper
- Milestone changed from Release 2.1 to Release 2.2
Moved at end of release 2.1
comment:3 Changed 8 years ago by Andrei Savici
Get Ei from a monitor and detectors. Refs #5105
Changeset: 07740d10fbcd79174fb5e30b67e62c79497b3227
comment:5 Changed 8 years ago by Andrei Savici
Get Ei from a monitor and detectors. Refs #5105
Changeset: 07740d10fbcd79174fb5e30b67e62c79497b3227
comment:6 Changed 8 years ago by Andrei Savici
- Status changed from accepted to verify
- Resolution set to fixed
The C++ version and test will be part of ticket #5686
comment:7 Changed 8 years ago by Michael Reuter
- Status changed from verify to verifying
- Tester set to Michael Reuter
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