[Halld-offline] HDGeant4 Meeting Minutes, May 19, 2020
marki at jlab.org
Mon May 25 18:58:31 EDT 2020
Please find the minutes from last week's HDGeant4 Meeting here
HDGeant4 Meeting, May 19, 2020,Minutes
Present: Alex Austregesilo, Sean Dobbs, Colin Gleason, Mark Ito (chair),
Naomi Jarvis, Richard Jones, Churamani Paudel, Joerg Reinhold, Justin
Stevens, Simon Taylor, Nilanga Wickramaarachchi, Beni Zihlmann
There is a recording of this meeting <https://bluejeans.com/s/TByqC/> on
the BlueJeans site. Use your JLab credentials to get access.
Review of minutes from the last Meeting
We went over [[HDGeant4 Meeting, May 5, 2020#Minutes|the minutes from
* Nilanga will close Issue #137
<https://github.com/JeffersonLab/HDGeant4/issues/137>, "K particle
gun request to resolve G3/G4 difference near p 0.5 GeV/c and theta
120 degrees" and re-open it as a halld_recon issue. There is concern
about loss of tracking efficiency in the backward region of the CDC.
Issues on GitHub
We reviewed some of the issues
Difference in Acceptance between G3 and G4 #111
We noted the one-year anniversary of this issue
<https://github.com/JeffersonLab/HDGeant4/issues/111>. We started with
comments entered yesterday (Monday). Colin showed plots where the
acceptance of charged pions can vary as much between the two hadronic
codes in Geant3 as from that in Geant4. Protons look similar among the
Richard commented that response of the calorimeters could depend on the
details of very low energy processes, including those of alphas and
neutrons and for the BCAL, that response depend a lot on whether the
interactions take place in the lead or in the scintillator. Recall that
the simulated BCAL is composed of a fictional, average lead-scintillator
compound. Saturation in the scintillator may be in play as well. For the
Cerenkov response of the FCAL there are similar uncertainties for the
response to low energy processes.
Sean suggested removing the requirement of matching of charged particles
to one of the outer detectors as a cross-check on the acceptance.
Colin also showed timing distribution of the various particle species in
his reaction. Differences in the photon timing resolution function for
the BCAL are seen between data and all Monte Carlo samples, a difference
that was not expected and needs to be explored further. He also showed
comparisons for timing from the time-of-flight. Here the pi^− show a
wide distribution for data than for Monte Carlo.
Sean showed some slides from Mark Dalton
shown at the May 16, 2019 Collaboration Meeting (one year ago), showing
comparisons between data and simulations of timing resolution for both
neutral showers and charged particles. He also showed offsets as a
function of energy, z, and run number for both neutral showers and
charged showers. He presented them as outstanding puzzles that this
group might want to address.
Pull Requests on GitHub
We looked at pull requests
<https://github.com/JeffersonLab/HDGeant4/pulls>. Richard has introduced
a new card <https://github.com/JeffersonLab/HDGeant4/pull/153> to allow
users to use the CCDB to specify the vertex position in the transverse
plane as well as the x and y spread of the beam. The information comes
from the measured position of two track vertices found in the tracking,
a facility developed by Simon.
Justin pointed out that this feature should be accessible via MCwrapper.
* This page was last modified on 25 May 2020, at 18:20.
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