GlueX Start Counter Meeting, March 5, 2015

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GlueX Start Counter Meeting
Thursday, March 5, 2015
10:00 am EST
CEBAF Center F326/327


  1. Announcements
  2. Review minutes from the February 12 meeting
  3. Detector Status
  4. Calibration
  5. DAQ Tasks for Spring 2015 Commissioning Run
  6. Action Item Review




Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2015 on the JLab CUE. This directory is accessible from the web at .


  • FIU: Mahmoud Kamel
  • JLab: Mark Ito (chair), Eric Pooser, Simon Taylor

Review of Minutes from the February 12 Meeting

We looked at the minutes.

The cable swaps we had during the Fall run have been fixed and translation tables have been installed both for the swapped configuration we had and the correct configuration we have now.

Detector Status

The start counter is cabled up and ready to go for the Spring run. All Hot Check-out tasks are complete. The detector has been surveyed on the target cart and is now in the bore.


Eric has been working on the time-walk calibration. He is doing comparisons with the corrections Simon obtained. The fitting procedure is done. He is looking for trigger dependence. The system is ready to obtain new corrections with new data when it comes in.

Mahmoud has been working on the correction for light propagation in the counters. He is dividing the counters into three regions: barrel, bend, and nose. He is comparing times from two counters hit in the same event, using tracking to determine the point where the particles cross the start counter. This is work in progress.

DAQ Tasks for Spring 2015 Commissioning Run

Eric, Mahmoud, and Werner Boeglin have come up with a list of tasks and issues for the upcoming run. We went over the entire list. Some items from the discussion:

  • Individual-channel discriminator thresholds will be possible this time.
  • Mark Dalton has a system for doing discriminator scans automatically. We would like to try it out for the start counter.
  • We need to ask if the online group is going to provide an automatic pedestal setting procedure for the F250s. If not we will have to adapt the procedure we used in the Fall.
  • We discussed increasing the time window, both for TDC and FADC hits. Eric found out that the FADCs can accommodate up to 4 hits per channel per event. We thought a large window would be good for that start counter since the channel count is so small.
  • Eric plans to re-write the online monitoring plugin. In particular he will have two plugins, one that relies on tracking and one that deals with only low-level quantities. An online efficiency calculation is planned for the tracking dependent plugin.
  • Eric will look into running the tracking-dependent plugin as part of the offline monitoring as a way to get started.

Meeting Time

We discussed moving the meeting time due to the now daily run planning meetings. 11:00 am was proposed, but no decision was reached.