February 20, 2007 Software

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  1. Review minutes from February 13, 2007 Software meeting
  2. Resolution Studies Slides.pdf (Alex)
  3. FCAL status (Mihajlo)
  4. Lab-wide software meetings (Elliott)
  5. Action items


Attendees:David L.(chair), Elke A., Simon T., Elliott W., Eugene C., Alex D., Elton S., Mark I. On the phone: Matt S., Mihajlo K.

Resolution Studies

Alex reported on a series of studies he's been doing on GlueX detector resolutions for varies reaction channels. In his method, he takes resolutions from GEANT-based simulation and tracking and combines that with knowledge of how the resolutions should scale with angle to produce an analytic form for the resolution of a charged particle with a given momentum and angle. This is applied to a couple of different reactions include rho production, rho pi production, and phi production. Some plots showing mass resolutions were shown. Also shown were some interesting plots showing how the helicity angular distributions are affected by cutting the acceptance for 0 degree, 1 degree, and 2 degree tracks. The effect is fairly dramatic for cos(θHEL) but has little or no affect on φHEL.

Also shown were the results of taking Mihajlo's multi-cluster vs. angle plot and using it as a map of the photon acceptance as a function of angle. This gives, in effect, a large inefficiency at around 10 degrees. This was used along with the charged particle tracking resolutions to produce plots of the theta angle for the b1 pi reaction in the Gottfried-Jackson frame when all effects are taken into account. The distribution again, looked quite distorted.

Matt noted that the exact shape of these distributions is not as important as our knowledge of them.

This work will continue as we get better results from the Monte Carlo to feed back into the parameteric calculator.

FCAL Status

Mihajlo continues to look into the nature of the multi-cluster issue at 10 degrees. He reported looking at the cluster to cluster separation which was often around 50-60cm. The distance of these from the projected cluster location was on the order of 100cm. More investigation is needed.

Lab-wide software meetings

Elliott reported that Sandy Philpott of the IT division is organizing a series of presentations/discussions on general software issues that will include experts from across the lab. The intent is to bring programmer type folks from the accelerator, physics, and IT divisions together to share knowledge and create connections with other local experts. Information will be passed on to the GlueX software group as it becomes available.

Action Items

  1. Put tarballs of external packages on Wiki(David)
  2. SVN web interface for browsing change logs(Mark I.)
  3. Experiment with shared pointers
  4. 12GeV Software Group meetings
  5. Place BCAL info on Wiki