May 1, 2007 Software

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  1. Review minutes from April 17, 2007 Software meeting
  2. Kinematic Fitter (Matt B.)
  3. Single photons in BCAL (Mihajlo) [1]
  4. Beam Test Analysis (Alex): Media:bcaltest.pdf
  5. Software/Calorimetry meeting schedule
  6. Portal/Wiki Security (Zisis P.)


Cebaf Center F324-325

To connect by telephone: 1.) dial:

800-377-8846 : US
888-276-7715 : Canada
302-709-8424 : International

2.) enter participant code: 39527048# (remember the "#")

We may have a VRVS connection depending if the equipment is in good working order. No guarantees.


Attendees: David L.(chair), Simon T., Eugene C., Elliott W., Elke A., Mark I.

On Phone/VRVS: Matt B., Zisis P., Matt S., Alex D., Mihajlo K.

Kinematic Fitter

Matt Bellis presented a kinematic fitter package written at CMU for CLAS in C++. see his slides at the link above.

The fitter has a simple, easy to use interface. The idea is that this could be useful for both CLAS12 anf GlueX as a general tool. Some modifications were suggested. These included adopting a standard kinematic data class that the fitter could take as input. The same class could be used to represent particles as input to an amplitude analysis. This is a concept CLEO has implemented successfully. This would simultaneously allow a path for detached vertex information to be passed into the fitter. The current fitter does not include detached vertices. It was suggested that this be placed in the 12GeV repository to be used by multiple halls.

Matt B. Agreed to place the document describing the fitter (CLAS-Note 03-017) on the GlueX DocDB so it would be accessible to GlueX members.

BCAL Reconstruction

The state of the BCAL simulation and reconstruction were discussed. It was pointed out that sampling errors are not included in HDGeant at the moment. Currently, HDGeant defines the BCAL as a single, solid, active material. The idea is still to perform detailed simulations of the BCAL response using the stand-alone simulation program at Regina. The results will be parameterized and included in HDGeant. The sampling errors are one of the largest contributors to the BCAL resolution. It will affect all energies and even change the shape of low energy distributions.

BCAL Beam Test analysis

We discussed the current state of the analysis of the beam test data as well as the plans for completing it over the next couple of months. Alex asked about energy calibration at different locations along the module. Blake said that the only calibration that has been done was for 90 degrees at the midpoint. He will check that the calibration is still valid for different positions/angles. Timing calibration was also discussed as were some plans to compare results with the Regina detailed simulation.

Christine wrote up a document on anlysis of the cosmic runs and will put that on the portal.

Action Items