Jun 5, 2009 Readout

Teleconference Time: 1:30 p.m. EST

• ESNET session

Tentative Agenda

The purpose of the meeting was to review what MC simulations were needed to support the decision on the Bcal readout.

1. Status (Matt). What exists and what has been studied.
2. What needs to be studied?
3. Who/how to best accomplish this list.

Minutes

Attending: Elton, David, Beni, Eugene, Sasha, Matt

1. Status (Matt). What exists and what has been studied.
   1. Digitization with SiPMs including realistic parameters for detector, thresholds to set occupancy. The simulation of timing is not very realistic.
   2. Reconstruction
      • Based on KLOE algorithm
      • Finds showers and reconstructs them, perhaps not optimized. Downstream programs exist to reconstruct pi0s.
      • Beni implemented the geometry to do the 3x3 inner FM PMT option. This is for the straight light guides, no implementation of impact of light guides on reconstruction.
   3. Documentation
      • Report at Apr 2, 2009 Calorimetry Meeting
      • See also GlueX-doc-849 and GlueX-doc-1231 for reconstruction references.
   4. Algorithm
      • Requires hits on both ends of the Bcal
      • Assumes that hits on only one side of the Bdal can be added in a second reconstruction pass
      • Finds clusters at the same radius (and delta phi). For showers in the same module, it attempts to separate them out along the beam line (z).
      • Eugene: for timing, hits will be discriminated with higher threshold.
      • Note: The GEANT threshold is currently very low, about 1 MeV in the Pb/fiber matrix. This way, different thresholds can be applied at the analysis stage.
2. What needs to be studied? (Based on e-mail list circulated by Elton). These items were discussed
   1. Two configurations under consideration Note: I do not mean to exclude studies that look at the effect of combining several segments electronically (e.g. vertical towers of 3 SiPM)
      1. (Nominal) inner 4x6 SiPMs, outer 2x2 FM PMTs
      2. (Alternative) inner 3x3 FM PMTs, outer 2x2 FM PMTs
   2. Tasks:
      1. study of the gap between the bcal and the fcal
      2. impact of combining channels together (towers of sensors)
         • pedestal noise (reduction)
         • changes in dynamic range
      3. tradeoff between PDE and DR for realistic track reconstruction
      4. backgrounds in light guides due to Cerenkov light
      5. reproduce studies on energy resolution for the two configurations using realistic thresholds
      6. timing resolution for the two configurations
      7. impact of these on a physics channel?
3. Who/how to best accomplish this list.
   • Add model for FM light guides to GEANT (Beni and Sasha)
   • Eugene: At the analysis we need to add a discriminator threshold, as well as realistic minimum requirements in the cells if timing is to be used
   • Cerenkov background in light guides (Sasha)
   • Once geometry with light guides is in, IU can redo acceptance studies of gap between Fcal and Bcal.