Opened 14 years ago

Closed 14 years ago

#118 closed bug (fixed)

wrong transmission?

Reported by: buter@… Owned by: srkline
Priority: minor Milestone: SANSReduction_5.1_Release
Component: SANS Reduction Keywords:
Cc: Blocking:


Thought I'd test this feature while I'm at it. Nice!!!

The actual issue is one I vaguely remember from before and may not be an issue (well it is to the extent that the users use it this way:-)

  1. Liu tried reducing some stuff on charlotte as the data was coming off but was getting some strange answers. When I came out and looked at it, he had done a number of incorrect associations so I started the whole transmission thing over. This is where I think I remember there being an issue when wanting to change the associations. At any rate, it does look like they get changed, but the transmission calculation is wrong. the emtpy cell went to 0.88. If I manually divide the intensities (total trans) from the two appropriate files I get 0.94 (which makes sense). So the question is .... where did 0.88 come from:-)

as for the feedback form... should anonymous be able to assign the "milestone?" or the task? or subtask? maybe doesn't matter at all, but thought I'd ask anyway since we are in Beta:-)

Change History (2)

comment:1 Changed 14 years ago by srkline

  • Component changed from Analysis to SANS Reduction
  • Milestone set to SANSReduction_5.1_Release
  • Priority changed from major to minor

Well, with wrong associations, I can guarantee that an empty cell transmission of 0.88 will happen, and I'l never be able to track down why.

For the incorrect assignment: there are two items on the SANSBeta menu that help out. FillEMPusingSelection will take the selected empty beam and associate it with all of the transmission files. ClearSelectedTransFiles? wipes out the trans assignment from a scattering file, and writes a 1.0 in for the transmission value. As always, if you get a value that doesn't look right, there's probably something that's being done wrong.

For the feedback form - I don't know if there's anything that can be changed about it. We don't have any notification system for new tickets. We just look and see, and reassign the ticket/milestone/etc. as appropriate.

comment:2 Changed 14 years ago by srkline

  • Resolution set to fixed
  • Status changed from new to closed

Turns out that the monitor count rate was not constant. In fact, it was about 7.5% different (low) for the empty beam measurement. The detector counts were correct. But when the data was rescaled to monitor counts, the empty beam counts scaled up, and transmission went to 0.88.

As part of the troubleshooting, MCR has been added as the last column of the File Catalog - and can be plotted for diagnosing oddities.

May need a "batch" way of patching raw data to appropriate monitor counts, or more simply copy the total count time into the monitor count field, which is equivalent.

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