GlueX Start Counter Meeting, September 22, 2016

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GlueX Start Counter Meeting
Thursday, September 22,2016
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. 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: Mahmoud Kamel
  • JLab: Thomas Britton, Mark Ito (chair)

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

Review of minutes from the last meeting

We went over the minutes from the meeting on August 26.

Sean Dobbs contacted about the monitoring and calibration plugins. Mahmoud needs the new-data-format-capable branch from David to look at the ADCs. He also needs new-format data to test changes.

Mahmoud is working on Python scripts to do calibration automatically, as Werner suggested last time.

Run Readiness

Mark, Eric Pooser, Tom Carstens, and Stephanie Worthington cabled up the start counter yesterday. The strain relief was not fully hooked up. Today they will do a test insertion and survey. The plan is to pull the target/start counter again and fully apply the strain relief on the cables.

The next step after that is to take some data and confirm the cables are connected properly.

Start Counter Efficiency

Mahmoud showed some slides on start counter efficiency. Captions are for:

  1. top left
  2. top right
  3. bottom left
  4. bottom right


  1. raw number of hits
  2. difference between track projection and center of counter
  3. time difference between prediction from track and start counter time
  4. 2-D plot of the previous two


  1. number of start counter hits (same as above)
  2. same after cuts on delta t (2.5 ns) and delta phi (18 degrees)
  3. ratio of the two

Projected SCHits.png

  1. number of time a track projects to a counter
  2. number of start counter hits in the sector with cuts mentioned above
  3. z distribution of track projections
  4. track vertex z vs. z dist. of track projections

This was work in progress. We spent quite a while on a nice discussion of basic approaches to calculating efficiencies. See the recording for details.