BCAL Readout Segmentation Task group Meeting: Aug 19, 2011

From GlueXWiki
Jump to: navigation, search

Meeting Info


  • 3:00 JLab
  • 1:00 Regina


  • CC F326-327


  • ESNet 8542553


Review action items from previous meeting

  • Read Zisis/Andrei's note and provide feedback (All)
    • (n.b. updates to previous meeting minutes are pending acceptance of this document)
  • Read Elton's e-mail above and circulate comments via e-mail (All)
  • Continue development of single cell resolution functions (Andrei/Irina)
  • Implement the following in step-based simulation study
    • Realistic input distribution in energy
    • Remove TDC contribution from outer layers
    • Implement timing and gain shifts between SiPMs
    • Calculate tavg

New Agenda items



David L., Elton S., Beni Z., George L., Andrei S., Matt S.

Extraction of sampling fluctuations in BCAL readout cells

Andrei showed some slides summarizing the latest Regina Monte Carlo calculations of the sampling fluctuations in the first 6 BCAL layers.

Slides 3,4, and 5: This indicated the general method employed. Namely, that both GEANT and FLUKA simulations were performed with the same geometry (1GeV and 0.5GeV photons incident at 90o) on the module. the FLUKA simulation had detailed geometry which included individual fibers while GEANT used a homogeneous material. The GEANT data was fit to the FLUKA data by smearing it using Poisson statistics allowing the sampling fraction and statistical contribution due to the sampling fluctuations to vary in the fit.

Slide 6: Statistical contribution due to sampling fluctuations plotted vs. BCAL layer number (fine segmentation scheme). This indicated a relatively strong dependence of the statistical coefficient with layer number (roughly 2/3% per layer).

Slides 7 & 8: Procedure repeated but with cuts on the energy deposited in the first layer. These indicated the dependence of the statistical coefficient on the cell in which the shower started.

  • Dave noted that the first blue point was not real since it represented a cell with effectively no energy. Without that, he did not see a strong trend that could be used in the simulation
    • Andrei noted that for layer 2, the two values (blue and red) had relatively small error bars and showed large differences.

Andrei indicated that these studies are continuing and will include data for different angles.

General Discussion

  • Cluster reconstruction for different segmentation schemes
  • Neutron reconstruction
  • Awaiting Fernando's response (next week?)
    • Tail wagging dog?

Action Items

  • Write up note on timing resolution studies by mid-week (David)
  • Continue studies on sampling fraction dependences, including angles (Andrei, Irina)