TDIS DAQ, 7 August 2017

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Organizational details

11:00 AM, CC A110

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Meeting URL



  • Kondo:
    • Discussed GET system/AGET chip (see talk)
      • similar to DREAM
      • talked to F. Sabatie, thinks AGET better than DREAM for rTPC
      • F. Sabatie is willing to put us in touch with Saclay developers, need to send our requirements so that they can help
      • Not done yet
    • Also discussed VMM chip
      • Signal peak ADC and tie information
      • No waveform
      • Might still work
    • Thinks best option is likely to work with Saclay to develop
    • PK comment: AGET would have same data rate constraint as DREAM, maybe VMM looks more promising
      • but, peak time may be late (~100ns)
      • need to find out if flexible/adjustable
  • Ed:
    • Discussed SAMPA chip (see talk) used in sPHENIX, STAR
      • new ASIC for ALICE TPC
      • all will use continuous readout
      • ALICE 1 TByte/sec
      • prototypes this year
      • shaper permits sampling at reasonable rates, ~20 MHz possible
      • 1.28 GByte/sec max off chip, need on-chip data reduction
    • NL comment: SAMPA may (not I think) be giving us an 80 ns peaking time, will go with 160 ns standard, a problem for us
      • Sao Paulo group would be willing to go back for ~$100k
    • SAMPA continued:
      • triggered - continuous mode possible, both time-stamped
      • "heartbeat" triggers
  • Paul:
    • Discussed general constraints, ideas for data rate and choices (see talk)
      • Trigger rate if we record all electrons in SBS ~6 kHZ
      • What about time and amplitude only?
      • What about only tracks that have good timing (would need at least some basic track finding)?
      • How many time bins?
      • Full reconstruction online (online processor approach)
        • NL commented that ALICE is trying similar approaches
      • Reduce 1-3 TByte/sec to 1-few GByte/sec via online cluster finding, etc.
      • Larger experiments doing this kind of online processing (FPGAs even), factors of ~10-15 reduction
  • Discussion:
    • Nilanga/Bogdan, summarize detector changes discussed after SBS collaboration meeting
      • 20 usec memory time higher than proposed (a problem)
      • may not need as good momentum resolution
      • how large does rTPC need to be?
      • Rachel to estimate, study ~few to 10 cm gap
      • talk for next meeting!
    • Design Option 2 - jet structure
      • discuss with drawings at next meeting
    • Design Option 3 - multiple TPCs with E, B, z parallel
      • 50 cm length divided into ~5 sections
      • Also can use faster gas to get to 1 usec
      • Kijun to simulate
      • talk for next meeting!
    • Nilanga/Kondo/Bogdan to present sketches/ideas at next meeting!
    • Kondo also looking at readout of rate new ideas
      • Discuss this as well at next meeting!
    • NL commented that hardware programming (data reduction, cluster programming,...) will also be important
      • need to work with more groups doing this
    • JZ pointed to a set of simulation plots that he has done (see link) looking at resolution, for VIPs 60-400 MeV
      • assumes 0.3 mm resolution on hit, 70/30 Ar/CO2
      • 100 hits along track
      • for current BONNUS12 tracking software
      • ~3% momentum resolution, 1 mm in z
    • We need to know what kaon momentum resolution we will need
      • k-TDIS will try to estimate for next meeting
    • PK had one other concern: background in physics region vs. worst? Will coordinate with Rachel.
    • KG asked if simulation covers ion flow-back also?
      • could be important
      • will need to simulate ions flowing back from the primary, also reduction of pressure/ionization density
      • Put on the to do list!