JEF meeting, June 3, 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: Sasha,Bill,Liping,Phil,Olga,Jon,Igal,Daniel,Tegan,Susan,Jane,Arshak,Jaden,Dax,Vadim,Jared,Adam,Gavin,S.T.

  • S.T. gave an update on simulation of the π0π0 background for η→π0γγ
    • Goal is to understand the shape and scale of the background
    • New generator genScalarRegge with parameters tuned to existing FCAL2 data
    • Use to estimate background for FCAL2 in anticipation of possible submission to PAC next year
  • Igal has been looking at shower seperations between π0 and bachelor γ for the golden JEF channel
    • Finds different distributions depending on how the decay post-processor evtgen is used
    • Some evidence that shower shape in Island Algorithm (IA) for lead glass blocks may not be correct
    • The default (DA) shower reconstruction algorithm does not work well when the showers are too close
    • The Island algorithm reproduces reasonably well the thrown separation when using the center-of-gravity (actually a fitted position)
    • The log-weighting method fails for close clusters for both algorithms, with a pronounced peak near zero separation for IA
    • Compared IA and default algorithm reconstruction of π0γγ relative to η→3π0 background
      • Peak in simulation at η mass looks sharper for FCAL2 compared to FCAL1
      • TOF veto reduces signal by factor of 4 but does suppress η→2γ peaking background
  • Tegan showed some shower separation plots from his di-photon studies
    • Confirmed poor performance of log-weighting method for position if the clusters are too close
    • IA works better than DA for center-of-gravity position method
    • Could in principle check IA using real data in CCAL following Ilya's scheme for mixing events used for PrimeX
  • No news regarding moving FCAL2 module fabrication setup to new building
  • Olga delivered a batch of cookies from GWU
  • PRs can now proceed: PMT sockets, integrating sphere
  • Got permission to move CRYTUR crystals from JLab pool to us
  • Students now at lab working on various stages of module fabrication, encouraged to give updates at this meeting
    • Checked 112 NPS replacement (SICCAS) crystals for color, bubbles, dimensions
    • Work on wrapping, cutting ESR/Tedlar,etc.
  • Need to glue/wrap light guides (1127 needed)
  • Grand total of 459 modules fabricated