GlueX TOF Meeting, January 22, 2015

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GlueX Time-of-Flight Meeting
Thursday, January 22, 2015
11:00 am EST
JLab: CEBAF Center F326/327


  1. Announcements
  2. Calibration Status
  3. Preparations for Spring Run
    1. DAQ tasks from last run
    2. DAQ tasks for this run



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 .



  • FSU: Hussein Al Ghoul, Paul Eugenio, Sasha Ostrovidov, Aristeidis


  • JLab: Mark Ito (chair), Simon Taylor, Beni Zihlmann


  • The weekly run coordination meetings are now being held at 8:45 am in the Counting House. Use the general GlueX number to connect with BlueJeans.

Calibration Status

  • Sasha is working on the time-walk corrections. He is suffering from low statistics for some PMTs, especially at the edges of the detector. He is referencing the TDC times against the times from the FADC firmware. He sees some quantization of the FADC times, this may be due to fast rising pulses with too few samples on the leading edge of the pulse.
  • Sasha has also started looking at the TOF hit factory to understand details of the code.
  • Simon has been using reconstructed tracks to map out the edges of the TOF counters. He sees gaps between the counters beyond the 6 cm width, as expected. The wrapping for each counter is 1 mil of Mylar and 2 mils of ESR but there is a contribution from departure from the ideal shape of the scintillators. When the arrays were put together there was 1/2 inch extra in total for one plan and 3/8 inch for the other, or very roughly 300 microns of gap. Mark thought we should also be able to look at the survey data to get an idea of the gaps. Hussein also has some numbers from measurements made during assembly.

Preparations for Spring Run

We went over Mark's recently updated list of DAQ tasks. Paul thought that the important task that we have not addressed is gain monitoring and equalization. We will try next to prioritize the work.