TDIS DAQ, 7 August 2017

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Organizational details

11:00 AM, CC A110

We will be using the BlueJeans system. To join via Phone:

1. Dial: 1-888-240-2560 (US or Canada only); other access numbers are available from bluejeans.com/numbers
2. Enter Conference ID: 491884270, and press #

Meeting URL https://bluejeans.com/491884270

Agenda

• Kondo - chip options other than DREAM: KG_tdis_20170807.pdf‎
• Ed - update about the SAMPA chip (used in the ALICE TPC upgrade) and its associated electronics: SAMPA talk.pdf
• Paul - data rate: Pking_tdis_20170807.pdf‎
• Jixie - tracking

Minutes

• 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!