GlueX Start Counter Meeting, December 15, 2016

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GlueX Start Counter Meeting
Thursday, December 15, 2016
11:00 am EST
CEBAF Center, Room F326/327


  1. Announcements
  2. Review minutes from the last meeting
  3. Corrections to Efficiency due to Accidentals (Mahmoud)
  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), Simon Taylor

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


We had some beam in the Hall last night. The solenoid was successfully ramped to 1,200 A. The tagger magnet is down; repairs are underway.

Review of minutes from the last meeting

We went over the minutes from the meeting on December 1. Mahmoud has started looking a the "survey" of the start counter paddles with charged tracks. He will report results when they become available.

Corrections to Efficiency due to Accidentals

Mahmoud has updated his start counter efficiency study to take into account accidental hits. See his slides for the details.

Accidental rate was measured by looking at sidebands of the SC hit time distribution. He measures the following overall efficiencies:

Before Accidental Correction With Accidental Correction
Simulation 97.5±0.2% 95.9±0.2%
Data 96.4±0.2% 95.4±0.3%

He showed efficiencies as a function of sector number. Also results for the straight, bend, and nose regions were shown separately.