JEF meeting, July 24, 2020

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Meeting time and location= 9:00 am EST (JLab time) Bluejeans only


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Agenda

  • SICCAS crystals
[1] [2] QA tests, Batch 1 -- Sasha, Josh

Minutes

Attendees: Jared,Zisis,Phil,Jon,Sasha,Igal,Tim W.,Jane,Tim B.,S.T.

  • μ-metal vendor now ready with new tooling, will deliver improved shields next week.
  • Expect light guide samples next week.
  • SICCAS originally indicated would deliver more crystals by end of July, but are delayed (some issues with powder needed for crystal construction?); Sasha will contact next week
    • Need to coordinate with Jane/Wuhan for QA checks
  • Sasha and Josh C have been able to perform some QA checks on the crystals we have in the TEDF
    • Moved micrometer from Hall C lab to clean tent: check dimensions
    • Visual inspections for chips, scratches, discoloration, presence of bubbles
      • Most look good, three appear to have discoloration -- maybe these can be improved by curing them with light?
      • Zisis asked whether company kept logs regarding temperature control and impurities -- Sasha seemed to believe these exist
      • After the meeting Phil Cole provided a master's thesis by one of this students about recovery of damaged lead fluoride crystals
  • Next week Sasha hopes to be able to start working on light yield setup in clean tent
  • Also plan to work on test setup on one arm of the pair spectrometer in the Hall
    • 3 slots occupied by Vlad B.'s scintillating glass, leaving 9 for our studies
  • Vlad P. has new resistor values for new PMT base design, still working on optimization, need to reduce divider current to below 1 mA due to HV supply limit, goal is 800 mu-A
    • Plan to have 2-3 version ready to test during beam time using COMCAL
    • Tim B. volunteered to do some bench testing at UNCW
  • Igal set up a wiki page with info about producing simulations for FCAL-II/JEF
    • Recommends using a run number like 90000 (to avoid confusion with existing run periods)
  • Jon Z. compared the efficiency of FCAL and FCAL-II for 1 GeV photon gun showing enhanced efficiency for angles < 5 degrees using FCAL-II
    • Igal requested CCAL be included in this study
    • Slight dip in efficiency at interface between insert and lead glass blocks
  • Jon Z. presented lists of eta decay channels currently available with extra evtgen package.
    • Also looked at pluto generator
    • Dalitz model for η→π0π+π- in evtgen dates from 1973, needs update!
  • Igal presented a study of the η→π0γγ channel
    • Looked at π0γ and γγ distributions, which have some non-smooth features that we need to understand
      • Due to proton reconstruction? Should study proton gun simulations.
    • Removed fiducial cut that was present in earlier analysis that effectively killed events with significant cluster energy in the insert
    • Looked at distributions as a function of number of clusters in insert
      • Compared FCAL-2 to FCAL: signal to noise improves for FCAL-2 relative to FCAL with number of clusters in insert region
    • For dark matter search need to characterize PDFs for narrow peaks in mass over the full available mass range. Phil C's student Jared will work on this. We have set up a wiki page for this and similar studies.
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