GlueX Start Counter Meeting, July 26, 2018

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GlueX Start Counter Meeting
Thursday, July 26, 2018
10:00 am EDT
CEBAF Center, Room L207
BlueJeans: 556 286 544


  1. Announcements
  2. Review minutes from the meeting on July 12
  3. Calibration and Efficiency
  4. NIM/TDR
  5. Action Item Review




Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2018 on the JLab CUE. This directory is accessible from the web at .



  • FIU: Werner Boeglin, 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.

Review minutes from the meeting on July 12

We went over the minutes.

Mahmoud talked to Sean Dobbs about updating the CCDB with the new propagation time corrections. Sean would prefer to leave the constants alone for now since the upcoming reconstruction launch is so close. Mahmoud is prepared to do the update for 2017 and 2018 at any time.

Time Resolution as a Function of Position

Mahmoud showed slides presenting his latest work on measuring the time resolution of the start counter as a function of position along the counter. These values can be used in mcsmear in favor of a single smearing constants as has been done before. Please see his slides for plots and the details.

He has settled on a four-region parametrization of the resolution. He is using this rather than a three-region version since the 2018 data shows some variation in the straight section not seen in 2017.


Both Werner and Mark spoke with Eric Pooser yesterday. He has been sidetracked with requests from Hall A/C management but will be able to return to working on the paper soon.