GlueX Start Counter Meeting, May 21, 2015

From GlueXWiki
Jump to: navigation, search

GlueX Start Counter Meeting
Thursday, May 21, 2015
10:00 am EDT
CEBAF Center F326/327


  1. Announcements
  2. Review minutes from the April 28 meeting
  3. Detector Status
  4. Calibration
    1. Propagation Time Discussion
  5. DAQ Tasks for Spring 2015 Commissioning Run
  6. Final Readiness Review Report
  7. Meeting Schedule
  8. 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 .


Present: Mark Ito (chair), Eric Pooser, Simon Taylor, Beni Zihlmann

Review minutes from the April 28 meeting

We went over the minutesfrom last time.

The bias scan was done during the Spring run. Results were reported by Mahmoud Kamel at the Collaboration meeting last week.

Propagation Time Calibration

Eric presented slides on the status of the propagation time calibration. He has tried several methods for fitting the dependence of the time difference between two hit counters vs. the hit position difference, where hit position is measured along the counter and is determined by charged tracks. He sees a few percent variation i the light propagation velocity depending on the fit method. The values are also significantly slower that those measured on the bench at FIU. See his presentation for details.

We had two suggestions for things to try:

  1. a cut on minimum energy using the FADC data
  2. restricting the fit region to positions with high statistics

Next Meeting

We will meet again in two weeks, on June 4.