[Halld-offline] HDGeant4 Meeting Minutes, September 11, 2018

Mark Ito marki at jlab.org
Wed Sep 12 12:18:51 EDT 2018


Please find the minutes here 
and below.

   -- Mark


    Minutes, HDGeant4 Meeting, September 11, 2018


  * *FSU: * Sean Dobbs
  * *JLab: * Thomas Britton, Mark Ito (chair), Simon Taylor
  * *W&M: * Justin Stevens

There is a recording of this meeting <https://bluejeans.com/s/iMoJk/> on 
the BlueJeans site. Use your JLab credentials.

      Review of minutes from last time

We reviewed the minutes from August 28 

  * The change to make the time-to-distance relation used in HDG3 match
    that of data (read it from the CCDB) is in the latest tagged version
    of halld_sim (3.4.0).
  * Sean reported that the 5 MeV shift in the 2γ mass he reported last
    time is not limited to just the BCAL or just the FCAL. Both contribute.

      Issues on GitHub

We reviewed the extant issues on the GitHub site for HDGeant4 
<https://github.com/JeffersonLab/HDGeant4/issues>. Richard Jones 
reported (via email) that he is working on the DIRC time propagation 
anomaly <https://github.com/JeffersonLab/HDGeant4/issues/65> now.

      New Comparison: 4 GeV, 4 Degree Protons

Thomas presented plots from a new comparison of 4 GeV, 4 degree protons 
between HDG3 and HDG4. The comparison was done with all physics 
processes (multiple scattering, energy loss, delta rays, etc.) turned off.

  * The good agreement after fixes from Richard for 4 GeV protons at 15
    degrees, seen after the last round of fixes, stays good in this
  * The disagreement at 4 degrees persists. It is seen in the following
      o Tracking FOM, wire-based
      o Tracking FOM
  * Thomas will work on getting more detailed plots looking at timing
  * Events have not been scanned, as was done in the previous round of
  * HDG3 and HDG4 get their geometry in different ways, with the HDG3
    geometry written into auto-generated Fortran code and HDG4 getting
    it dynamically at run time. We need to check that both are using the
    same geometry for this comparison. That could explain the difference
    between 4 and 15 degrees (or not).
  * Thomas will create a new GitHub issue based on this study. [Added in
    press: see Issue #66

Retrieved from 

  * This page was last modified on 12 September 2018, at 12:16.

Mark Ito, marki at jlab.org, (757)269-5295

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