GlueX Offline Meeting, April 15, 2015

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GlueX Offline Software Meeting
Wednesday, April 15, 2015
1:30 pm EDT
JLab: CEBAF Center F326/327


  1. Announcements
    2. F1TDC Timing, CCDB (Paul M.)
    3. CAEN TDC time scale (Mark)
  2. Collaboration Meeting
  3. Review of minutes from April 1 (all)
  4. Offline Monitoring (Kei)
  5. EM background simulation
  6. Geant4
  7. Action Item Review

Communication Information

Remote Connection


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 .



  • JLab: Alex Barnes, Sean Dobbs, Mark Ito (chair), David Lawrence, Paul Mattione, Kei Moriya, Eric Pooser, Nathan Sparks, Mike Staib, Justin Stevens, Simon Taylor, Beni Zihlmann
  • MEPhI: Dmitry Romanov


  1. RUNNO FFREAD card in HDGEANT. Mark introduced a new FFREAD card for HDGEANT. If the new RUNNO card gives a non-negative value, it will use that value to initialize the calibration database and initialize the run number. Run numbers encoded in HDDM events will overwrite this run number. The motivation was to have particle gun events will use this value; before now getting the correct calibration constants was a problem. David suggested having this card overwrite the value in the HDDM file.
  2. F1TDC Timing, CCDB. Paul led us through his email. F1-TDCs are now referenced to the TI counter rather than the measured trigger time. On another front, he has changed the RF constants tables in the CCDB. Old SQLite files are invalidated with this change.
  3. CAEN TDC time scale. Mark circulated an email from Ben Raydo making explicit the method for calculating the size of the time bin for the CAEN 1290 TDCs we use for the TOF. Last week Paul discovered that using 25 ps per bin gives the wrong separation of the RF pulses going into the CAENs. Turns out that 23.4375 ps is the right number.

Collaboration Meeting

We put together a tentative agenda:

  1. Overview, Mark, 30 min.
  2. Calibration, Sean, 45 min.
  3. Timing Calibration, Mike, 15 min.
  4. Offline Monitoring, Kei, 30 min.

Review of minutes from April 1

We went over the minutes.

The b1pi and single-track tests are running successfully now.

Offline Monitoring

Kei showed slides summarizing recent improvements to the offline monitoring system. We also went over some of the pages in his collection of launch statistics. Included in his slides were new comparisons of key job performance characteristics, launch-to-launch, such as CPU time and memory use. Launch 13 is underway now. See his slides for the details.

EM background simulation

David described his system for combining hits from two event HDDM event streams. The streams need not have equal numbers of events. The short stream is recycled to provide events to combine with each event of the long stream. This provides a mechanism for mixing a small sample of electromagnetic background events with a sample of simulated physics events.

Just asked if there was a way to combine EVIO-formatted events with HDDM events. That we we could use random triggers from GlueX to provide the electromagnetic background. There is not a mechanism at present, but Paul thought it would be straightforward to convert EVIO data to HDDM.

Sean volunteered to start playing around with David's event combination system.


David has been working on a Geant4 implementation of a GlueX simulation in the context of the charged pion polarization experiment. He hopes to be done in a week or two.