GlueX Offline Meeting, December 1, 2010

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GlueX Offline Software Meeting
Wednesday, December 1, 2010
1:30 pm EST
JLab: CEBAF Center F326/7


  1. Announcements
    1. New release: sim-recon-2010-11-29
  2. Review of minutes from the last meeting: all
  3. Software responsibilities for TOF and Start Counter: Mark
  4. Calibration Database Update: Dmitry
  5. FLUKA simulation of neutron flux: Sascha
  6. Action Item Review: all
    1. Resolved issues
    2. Outstanding issues
    • To view these links, login first. Anonymous login is available.
  7. Review of recent repository activity: all

Communication Information


To connect by telephone:

  1. dial:
    • 800-377-8846 : US
    • 888-276-7715 : Canada
    • 302-709-8424 : International
  2. enter participant code: 77438230# (remember the "#")

Video Conferencing


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2010-12 on the JLab CUE [1]. This directory is accessible from the web at .



  • IU: Ryan Mitchell, Kei Moriya, Brad Schaefer, Matt Shepherd
  • JLab: Hovanes Egiyan, Mark Ito (chair), David Lawrence, Lubomir Pentchev, Elliott Wolin, Beni Zihlmann


Mark reminded us about the latest release of sim-recon, sim-recon-2010-11-29. See his email for details.

Software responsibilities for TOF and Start Counter

We went over the nominal assignments of responsibilities for reconstruction of the TOF and start counter. The amended list will be:

  • TOF: Paul Eugenio and Beni Zihlmann
  • Start Counter: Werner Boeglin, Simon Taylor, Sascha Somov

Mark will ask the principals to summarize status at a future meeting.

FLUKA simulation of neutron flux

Sascha reviewed recent work on simulating radiation damage, especially, but not limited to, that from neutrons in Hall D. The original motivation was to study damage rates to SiPM's that will be used to read-out the BCAL. As such, damage on silicon was studied. Also Sascha and his collaborators Pavel Degtiarenko, Alberto Fasso and George Kharashvili were interested in comparing the results of GEANT3 and FLUKA. Sasha led us through the plots on his wiki page. The agreement between the two systems was better than a factor of two, which is considered pretty darn good.

The version of FLUKA that has had the most recent development is a stand-alone package with its own geometry system. Most of the work was in capturing essential features of the GlueX detector geometry in FLUKA.

A glance at the plots shows that the fluence in the area just upstream of the start counters is within a factor of a few of that in the region of the BCAL SiPM's indicating that SiPM's are not excluded from consideration for the readout of that detector.

There might also be application of this set-up for estimating dose to the FCAL insert. The damage to lead glass is of a different nature than that to silicon and that would have to be taken into account.

Action Item Review

  • David has eliminated a bunch of warnings that were coming from the tracking code.

Review of recent repository activity

  • David has been working on the simulation apparatus for the Compton calorimeter being proposed for the η Primakoff experiment.
  • Simon eliminated some warnings with judicious placement of {}'s in the mcsmear package.


David raised the question of converting the Monte Carlo from GEANT3 to GEANT4.

  • Mark reported that Richard Jones is working on an implementation. It gets its geometry from an HDDS file. The new geometry system does not generate code that then gets compiled. Rather a geometry-agnostic binary reads the HDDS directly and creates the geometry on the fly.
  • David thought that we need it sooner rather than later, and that later might turn out to be never.
  • Mark thought that we are not dead in the water using GEANT3 and we do have a nominal effort in progress. That might be the appropriate effort level.
  • Elliott thought that we need to hire someone to do the job. We have been saying that a new collaborator might take this on, but we have been saying this for a long time.
  • Mark shelved the discussion as it seemed that no end was in sight. We will have to return to this question.

New Action Items

  1. Get a report on start counter reconstruction.
  2. Get a report on time-of-flight reconstruction.


  1. You have to be a member of the "halld" Unix group to do this.