HDGeant4 Meeting, November 29, 2021

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HDGeant4 Meeting
Monday, November 29, 2021
9:30 am EST
BlueJeans: 968 592 007


  1. Announcements
  2. Review of minutes from the last meeting (all)
  3. Issues on GitHub
  4. Pull Requests on GitHub
  5. Action Item Review


Present: Alex Austregesilo, Sean Dobbs, Mark Ito (chair), Igal Jaegle, Richard Jones, Simon Taylor, Beni Zihlmann

There is a recording of this meeting on the BlueJeans site. Log into the BlueJeans site first to gain access (use your JLab credentials).


There will be a meeting at 4 pm tomorrow to discuss preparations for the upcoming Computing Review.

Review of minutes from the last meeting

We went over the minutes from the meeting on November 15. Richard repeated his report of a possible issue where timing signals from the FCAL do not agree between data and MC. There was a report of seeing accidental peaks in the raw timing histograms in simulation where in data they do not appear. Richard explained that In data, one needs to subtract the RF to get peaks; in simulation, if one does the same thing, the seen-in-raw-hits peaks persist. By doing time-difference-to-time-difference comparisons, there is no mystery, and these are the only comparisons we should be doing anyway. He is waiting for confirmation of this understanding from the folks who raised the issue.

Issues on GitHub

We looked at the Issues.

  • Data/MC discrepancy in FCal Matching around Beam Hole
    • Other than the difference in track matching to the FCAL in data vs. simulation, initially noted by Alex, Igal raises a lack of calibration of 2017 data for the inner blocks.
    • It is not clear that a fiducial cut is needed to exclude inner blocks from their role as a backup t-zero setter for tracking. The energy is not used, only the time and position in this context.
    • Sean will review the status of the 2017 calibration.
  • Crash adding daughters on RHEL/CentOS 8
    • We think this one is resolved but are still waiting for Hao Li to confirm the fix.
  • Add incident angle dependence to DIRC mirror reflectivity
    • This enhancement remains on the books. Richard will consult with the DIRC folks to see if they have done any further thinking on this. In principle, implementation is straightforward.