JEF meeting, August 12, 2022

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Meeting time and location:

  • 9:30 am EST (JLab time) remote only
  • Zoom meeting ID: 161 050 9142 Passcode: 004965



Attendees: Igal, Sasha, Tegan, Arsak, Phil, Zisis, Liping, Bill, Jon, Jane, Olga, Azizah, Susan, ST.

  • Igal gave an update on his cluster separation studies.
    • Showed results from HyCAL analysis showing separation with fairly large efficiency below 2 cm down to 1 cm for the lead tungstate and below 4 cm down to 2 cm for the lead glass blocks using the island algorithm (IA)
      • Liping: normally incident leptons, not photons
      • Position of incident particle determined using beam profiler
      • Two clusters overlayed
      • Lead tungstate results show obvious step behavior; much less sharp for lead glass
      • This step behavior not seen for simulated CCAL 2-cluster (photon) events, and the efficiency drops off faster as a function of d
      • Both analyses used same algorithm, one in Fortran and one in C++ ported directly from the Fortran code
        • Several hard-coded parameters -- need to be tuned?
        • Other potential differences: Geant3 vs Geant4 for shower profile?
    • Looked at xy positions on modified CCAL -- not all features understood
  • Fabrication update
    • Received all Crytur crystals from second order + 5 more from pool
    • Ordered 50 more, to arrive March/April
    • All crystals wrapped, some wrapping for earlier modules have been fixed
    • Ran short of strips for brazing, have been ordered
    • PMT housing bottleneck, expect more to arrive this week
    • Some PCB alignments needed to fixed (need to be vertical)
    • Grand total fabricated modules=1153, need to do inventory, prepare shelves for move to new space in EEL (still under construction)
  • Arshak working on studying and trying to improve light uniformity over the extent of the plexiglas for the LMS
    • Tried different reflectors on wide face of plexiglas
    • Still more intense near boundaries
    • Try LEDs instead of fibers? Try more fibers?
    • Need to set deadline for going with this approach as opposed to HyCAL method.