GlueX Offline Meeting, May 16, 2012

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GlueX Offline Software Meeting
Wednesday, May 16, 2012
1:30 pm EDT
JLab: CEBAF Center, F326/327


  1. Announcements
    1. Group disk quota increased, halld
    2. Request submitted to IT for mirror mysql server
  2. Review of minutes from the last meeting: all
  3. Collaboration meeting agenda
  4. Reconstruction sub-group reports
    1. Calorimeters: Photon Reconstruction in b1pi events 04/25/2012 (Will)
    2. Tracking: Spiral Track Update (Paul)
    3. PID
  5. Start Counter geometry changes: Simon
  6. Offline Software Review Planning
  7. Action Item Review
  8. Review of recent repository activity: all

Communication Information

Video Conferencing


Talks can be deposited in the directory /group/halld/www/halldweb1/html/talks/2012-2Q on the JLab CUE. This directory is accessible from the web at .



  • CMU: Will Levine, Paul Mattione, Curtis Meyer
  • IU: Matt Shepherd,
  • JLab: Mark Ito (chair), David Lawrence, Simon Taylor, Elliott Wolin, Beni Zihlmann


  • The halld group disk almost ran out of space yesterday. Some clean-up was done and the quota was increased from 105 GB to 125 GB. David asked about the cost of this form of disk storage. No one present could answer so he will look into it.
  • A formal request for a new MySQL server has been submitted to JLab IT. The new server will mirror the calibration database and will allow read-only connections from off the JLab site. Agreement for such a configuration was agreed to some months ago.
  • There will be a special session for upgrades at the Collaboration Meeting next week. Richard will present his work on Geant4 in that session.

Review of minutes from the last meeting

We reviewed the minutes from the April 18th meeting.

  • On simulating sampling fluctuations in the BCAL, David reported that Elton Smith has summarized the discussion held when Andrei and Irina Semonov(a) were here. Work on this is planned for the summer.

Collaboration Meeting Agenda

The current schedule for the offline session:

Tuesday May 22, 2012
11:30 Session IIIc (75) --- Offline - Chair: R. Jones
   11:30 (25) --- Overview - Mark Ito
   11:55 (25) --- Tracking Update - Simon Taylor
   12:20 (25) --- Calorimetry - Will Levine

Reconstruction sub-group reports


Will gave a report on photon reconstruction in b1pi events. See his wiki page for details. He showed reconstruction studies for the BCAL and the FCAL for two cases:

  1. Standard full event reconstruction of b1pi events
  2. Individual photons and charged particles were selected kinematically from the b1pi generated events, but were simulated one photon (or pion, or proton) at a time.

In the full event sample, reconstructed "photons" has a contamination from pions at low energy, as seen by comparing to the distribution from one-at-a-time pions. He also showed distributions of other cluster properties that might help distinguish between charged particles and photons.


Tracking Code Improvements

Simon mentioned two"

  1. There was a low momentum cut-off for protons at 350 MeV/c that he noticed while working the the rare eta decay proposal. This has improved due to recent changes.

low momentum protons, rare eta 350 MeV/c cut-ff seen improved

  1. He has been working on the track recovery code, code that addresses kinks and other "broken" tracks. The chi-squared distributions are improving.

Spiral Track Update

Paul showed recent improvements in reconstruction efficiency for the 90 degree pions at 1.1, 1.5, and 2.1 GeV/c. See his wiki page for details. He also showed distributions of the difference between thrown and reconstructed track parameters for track candidates and for time-based tracks. He also showed these plots for 60-degree pions.

He is testing ideas to improve this area of phase space. Recent changes from Simon in hit pruning my help.


Paul will be working on PID studies related to a new Cerenkov counter after the collaboration meeting.

Start Counter Geometry Changes

Puneet and Simon have put in changes to the start counter geometry into HDDS and HDGeant. Also some calibration files have changed to track these changes. The new geometry has a 30-counter arrangement. The old one had 40.

The target scattering chamber dimensions have also changed recently and the new values were included in this update.

We will need a new tagged version of HDDS, sim-recon, and calib. Mark will work on that.

Offline Software Review Planning

David updated us on the status of the preparation effort. He urged us to review the draft talks at on the review planning wiki page and give the authors' feedback.

Curtis also mentioned that there was a set of written material that needs to be put together still.

Action Item and Repository Activity Review

We did this. A wonderful time was had by all.