General Meeting Summary 3/31/16

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BACKGROUND STUDIES

  • Discussion about Vardan's GEANT4 simulation
  • shows a background reduction, in particular for electrons, that is different from that shown in Vardan's earlier studies and also David Hamilton's GEANT4 studies.
  • depending on the charged background reduction prediction may want to consider a charged particle absorber in front of the calorimeter (DVCS/HA used 10 cm of plastic - absorbs electrons up to 20 MeV)
  • Action item: check implementation and also compare to previous results


UPDATE ON HV DIVIDER STUDIES

  • Discussion of gain stability studies with C-W base design with PMT and APDs
  • APD-based readout could be interesting if magnetic fields are too strong to shield from
  • To compare to our current default active base design need to have gain stability as function of anode current for C-W bases - a double-LED setup may be advantageous to use for these tests
  • may want to correlated jitter in output signal to input driver
  • Follow-up to question about radiation damage to processor from Hall C January meeting
  • may not be an issue as it is possible to separate digital part from calorimeter by sufficient distance - requires ribbon cables, but still not as many as with default base design
  • Action item: determine linearity at high rate for C-W bases
  • check against default base parameters
  • include amplifier in base
  • must have test with amplifier done before September 2016


MAGNET UDPATE

  • Discussion about magnet budget for machining the steel (now at JLab) and coil
  • machining and procurement of conductor require design drawings - ongoing activity
  • Discussion about most recent design update from M. Fowler
  • interferences at small angles require a specialized beam pipe - cannot complete magnet design without this
  • Hall C beam line design is currently ongoing, so good time to take this into account


ITEMS FOR NEXT MEETING:

  • Follow-up background study (Vardan)
  • Magnet updates
  • Other Action Items from list, e.g., magnetic shielding of PMTs, support structure and frame
  • Other...


NEXT MEETING: THUR 21 APRIL, TIME: 9:00 AM (EDT)