GlueX TOF Meeting, August 22, 2017

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GlueX Time-of-Flight Meeting
Tuesday, August 22, 2017
11:00 am EDT
JLab: CEBAF Center, Room F326/327


  1. Announcements
  2. Review of minutes from the previous meeting
  3. Calibration Status
    • Time Calibration
    • Energy Calibration
  4. PMT testing
  5. Active dividers
  6. Counter reconfiguration
  7. NIM Paper (Paul)
  8. Action Item Recap



Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2017 on the JLab CUE. This directory is accessible from the web at .



  • FSU: Brad Cannon, Sasha Ostrovidov
  • JLab: Thomas Britton, Mark Ito (chair), Simon Taylor, Beni Zihlmann

There is a recording of this meeting on the BlueJeans site.

Review of minutes from the previous meeting

We looked at the minutes from July 11.

The HV mainframe that Paul identified on his trip to JLab is ready to go, pending signature on the shipping authorization form.

Calibration Status

Time Calibration

Beni gave a report.

  • The new timing calibration, using the pulse amplitudes rather than the pulse integrals are now being used in the default version of the software.
  • Last week, new tables were added to the MC variation. The code was complaining about a lack of constants even though they are not needed for simulated data.
  • Paul Mattione reported that in the plot of tTOF−tRF vs. momentum there is a 300 ps. offset. Beni checked that with the old calibration, there was still an offset of 100 ps.
  • Sean Dobbs reported that the new constants introduced an offset in the times of the TDCs relative to corresponding ADC time. Beni is doing a new channel-by-channel calibration which is in progress. Since the calibration requires tracking and retrieval of files from the tape library, this is taking a while to get through (time scale weeks).
  • After this final calibration step is done, the next items are to
    1. clean up the code
    2. update the documentation
  • Runs 30,000-30,274 had no TOF calibration constants defined. Although there are no real runs in this range, Beni assigned constants in case simulated data needs them.

At tomorrow's Analysis Meeting Beni will present the results of his TOF efficiency study, based on material already published in the wiki.

Energy Calibration

Brad will give us a report at the next meeting.