GlueX Start Counter Meeting, October 20, 2016

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GlueX Start Counter Meeting
Thursday, October 20, 2016
10:00 am EDT
CEBAF Center, Room F326/327


  1. Announcements
  2. Review minutes from the last meeting
  3. Calibration/Efficiency Update
  4. Run Readiness
  5. NIM/TDR
  6. Meeting time change? 11:00 am?
  7. Action Item Review




Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2016 on the JLab CUE. This directory is accessible from the web at .



  • FIU: Werner Boeglin, Mahmoud Kamel
  • JLab: Thomas Britton, Mark Ito (chair), Paul Mattione, Eric Pooser, Simon Taylor

There is a recording of this meeting on the BlueJeans site.


  • There will be no beam until after Thanksgiving. [Added in press: beam is now due November 17.]
  • The target has not been pushed into the bore yet.

Possible start counter hole?

Mahmoud noticed a "feature" of the start counter geometry. He discussed this with Sean and the discussion moved to an [ issue on GitHub]. Please see GitHub for the details and plots of the effects. Paul and Mike Staib contributed studies and Simon found and fixed the root problem in the algorithm for determining the intersection of charged tracks with the start counter.

Run Readiness

  • The start counter has not been pushed into the bore yet.
  • Sascha Somov told Mark that the problem preventing read-out of the TDC crate a couple of weeks ago has been solved. The download of new TI firmware in that crate had been interrupted before completion and so the TI was unsurprisingly non-functional. The full complement of firmware has since been downloaded.
  • Sascha also mentioned he is seeing very occasional corruption of TDC data from this crate. It appears on a hour-ish timescale and does not affect subsequent events in the run. The cause is unknown at present.


Yesterday, Paul sent Mahmoud a description of how he pictures doing the efficiency measurement. We had some significant discussion, but nearly all of it had to do with definition of terms (what is a "hit") and the cuts used in the efficiency tree that Paul wrote. Paul did note that there is a loose timing cut relating the track to the start counter and the information for the user to apply a custom cut will be present in a future version of the tree.


Eric has started on writing the NIM-article/TCR. In parallel he will put together a contribution to the TDR. He plans to use the ShareLaTex platform.

Meeting time change

We decided to move the meetings from 10 am to 11 am. We will keep the same day, every two weeks on Thursday.