GlueX Start Counter Meeting, January 24, 2019

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GlueX Start Counter Meeting
Thursday, January 24, 2019
10:00 am EST
CEBAF Center, Room L207
BlueJeans: 556 286 544


  1. Announcements
  2. Review minutes from the meeting on January 10
  3. Calibration and Efficiency
  4. SiPM bias currents (Beni)
  5. NIM Paper
  6. Action Item Review


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2019 on the JLab CUE. This directory is accessible from the web at .



  • FIU: Mahmoud Kamel
  • JLab: Thomas Britton, Mark Ito (chair), Simon Taylor, Beni Zihlmann

There is a recording of this meeting on the BlueJeans site. Use your JLab credentials to authenticate.


Hot Check-Out for the Start Counter needs to be done by the end of the week. Beni is going to take care of the remaining steps.

Collaboration Meeting

We agreed that there is no need for a Start Counter presentation at the upcoming Collaboration Meeting.

Review of minutes from the meeting on January 10

We went over the minutes. We are still thinking about a Start Counter Maintenance Program.

SiPM Dark Rate

Beni has been thinking about how to monitor dark rate in the SiPM's. The classic approach is to integrate charge in some gate and count the number of one pixel, two pixel, etc. events above pedestal. It is not clear such an approach would work in the Hall with the FADC's. Still perhaps a look at total charge above a cut above threshold might work.

Beni has been written a plugin to create histograms and has a plan for analyzing them. The plan is to run with the beam off, with no sparsification of FADC read-out, and a clock trigger at roughly 1 kHz. This will require a special DAQ configuration, but Sascha Somov has told us that that is not a problem. We might consider reading out the other SiPM-based detectors at the same time (BCAL, PS, TAGM). The run should not take much time and needs to be done when there is no beam, so it need not compete with real data taking. We will try a test next week to see what the data looks like.

NIM Paper

No new news on the NIM paper.