HDGeant4 Meeting, August 14, 2018

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HDGeant4 Meeting
Tuesday, August 14, 2018
2:00 pm
JLab: CEBAF Center, A110
BlueJeans: 968592007


  1. Review of notes from last time
  2. New HDGeant4 tagged release
  3. Comparison post FDC fix(es)
  4. Issues on GitHub (all)



  • FSU: Sean Dobbs
  • JLab: Thomas Britton, Mark Ito (chair), Justin Stevens, Simon Taylor, Beni Zihlmann
  • UConn: Richard Jones

There is a recording of this meeting on the BlueJeans site. Use your JLab credentials.

Review of notes from last time


New HDGeant4 tagged release. This one has Richard's FDC fixes.

Comparison post FDC fix(es)

Thomas showed distribution after fixing. See page 17 of the files posted here.

  • First attempt at comparison had problems with wrong tagged version of HDGeant4 and a mis-set JANA_CALIB_CONTEXT.
  • Protons at 4 GeV/c at 15 degrees polar angle look much, much better.
  • Still a problem with protons at 4 GeV/c at 4 degrees.
    • FOM distributions on page 23 and 24 are very different.
    • Will repeat turning off mult. scattering, energy loss fluctuations, position resolution smearing.
      • [added in press] the control file for this comparison can be found at Gcontrol_pure.in.
    • Time-to-distance relation (TTDR) between Monte Carlo (MC) and MC reconstruction not consistent.
    • Simon will look at using same TTDR as used for data in both MC and MC reconstruction.


We reviewed the issues on GitHub.

  • Geometric overlaps still on the list.
  • Thomas will mark the FDC issue resolved and/or start a new FDC issue as appropriate.

Next Generation of Signal MC

We will wait for further study of FDC issue and adoption of consistent TTDR before starting a new round of Signal MC.