Ticket #755 (closed: fixed)
Gravity correction
Reported by: | Nick Draper | Owned by: | Russell Taylor |
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Priority: | major | Milestone: | Iteration 21 |
Component: | Keywords: | ||
Cc: | Blocked By: | ||
Blocking: | Tester: |
Description (last modified by Nick Draper) (diff)
From RKH:
Due to the wider range of wavelengths (poss 0.5 to 14 angstrom) and longer distances on SANS2d than on LOQ we really do need to put gravitational droop in. The drops are frequently much more than the precision with which we can determine the beam centre, and significant for the Q value calculation at the longest wavelengths. I think it should go fairly easily into the wavelength to Q calculations. Would help to have a global variable to turn gravity on or off.
Drop ~ 0.000313 lambda2 L2 with lambda in angstrom and sample to detector L in metres. (see attached file)
We won’t worry about the very fine detail of the parabolic paths between sample and detector being slightly longer than the straight line one.
There is an issue as to what wavelength the vertical coordinates on the detector correspond to. We could say they are correct at zero angstrom (as per a tape measure survey) or at some given wavelength, say 4 angstrom, which makes it easier to relate to displays of data.
The latter would suit SANS but I suspect the former would be more logical and transferable to other beam lines ?
Attachments
Change History
comment:2 Changed 11 years ago by Nick Draper
- Milestone changed from Iteration 19 to Iteration 20
Moved as part of the end of Iteration 19
comment:3 Changed 11 years ago by Nick Draper
- Owner changed from Nick Draper to Russell Taylor
- Description modified (diff)
Required for reflectometers and SANS.
Get Tim, Rob and SANS guys in a meeting room about this one.
comment:10 Changed 11 years ago by Russell Taylor
comment:11 Changed 11 years ago by Russell Taylor
comment:12 Changed 11 years ago by Russell Taylor
comment:13 Changed 11 years ago by Russell Taylor
comment:14 Changed 11 years ago by Russell Taylor
comment:15 Changed 11 years ago by Russell Taylor
comment:16 Changed 11 years ago by Nick Draper
comment:17 Changed 11 years ago by Nick Draper
comment:18 Changed 11 years ago by Russell Taylor
comment:19 Changed 11 years ago by Russell Taylor
comment:20 Changed 11 years ago by Russell Taylor
comment:21 Changed 11 years ago by Russell Taylor
comment:22 Changed 11 years ago by Russell Taylor
comment:23 Changed 11 years ago by Russell Taylor
comment:24 Changed 11 years ago by Russell Taylor
- Status changed from accepted to testing
- Resolution set to fixed
Assume this is doing the right thing for gravity, as far as its ambition goes (at least I haven't had any complaints). There may be refinements requested later.
comment:25 Changed 11 years ago by Anders Markvardsen
- Status changed from testing to closed
Although update Wiki for Q1D a bit to include short description of what the format required for the QutputBinning property and also mention that gravity correction now included.
comment:26 Changed 5 years ago by Stuart Campbell
This ticket has been transferred to github issue 1603
Moved as part of iteration 18 end