CountingDaq 220304

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Meeting information

 Meeting time:  12:00pm Eastern
   
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Agenda

  • Activity updates
    • Small update to data rate estimates in DocDB 863; single event builder should still be fine.
  • General discussion

Minutes

Recording on Zoom: [1]

Participants: R. Michaels, B. Moffit, P. King, D. Armstrong, C. Ghosh, H. Liu, M. Gericke, D. McNulty

  • Brief update on the data rate calculations
    • If we keep event rate at 5kHz, and have full raw readout of a 256ns window on the FADC and a 30% occupancy on the GEMs we'd have about 1 GB/s. SBS has been able to run with this sort of data and event rate in production with one Event Builder.
      • Chandan reminds us that xrays can be produced on the apertures and windows just upstream of the GEMs.
      • David has not had a chance to look at xrays on the GEMs in the simulation file he has from Chandan
      • This is probably a reasonable upper limit on the data rates we'd have (pending determination of the xray backgrounds in the GEMs). Note that even at the 100 pA beam currents our event rate can still be at the few kHz level since the Mollers will still be in the tens of KHz per sector.
  • Brief update on Bob and Paul's discussion with Chris about FADCs
    • We ask Bryan if he remembers if the VTP was used to do the helicity integrals for the Compton. Bryan says that he recalls it just being used for triggering
  • Bob is working on recovering the Compton DAQ in the TEDF test stand
  • John Musson will be presenting beam monitor instrumentation status and plans on March 18; this would be intended to get the beginning of an understanding of how to get the data into both counting and integrating DAQs.
  • David mentions that during SBS Gmn, only two cards had failed out of ~380 cards installed. It is not clear if they had died due to radiation or due to some other issue. So the attrittion rate of the the APVs is fairly low.
  • Michael reports that Jie finished the dual-mode preamplifier that would go into the PMT base assembly. She'll submit for construction of the prototype soon.