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Agenda

  • Operations
    • Run 67 (re-run of USD1) finished
      • 1K Pot developed issues - fridge failed overnight Friday
        • seem to have lost some mixture. after failure, fridge pressures were low, base temperature was elevated. But running still heater brought base to lower than before
        • after pumping back to dump, 727 mbar of mixture; previously 738 mbar (1.5% lost)
      • More measurements taken:
        • compare long bake to short flash: no noticeable difference
        • take Ba-133 data: can't resolve 356 line. The peak in 60keV charge collection efficiency occurs sooner with elevated event rate.
        • warm tower to 130mK and take data: no noticeable difference
        • look at data before bias is applied and after bias is removed. No peaks seen before - but after, we see an apparent reverse bias for a while.
        • Nick did some more calibration with test signal input
      • Trigger rate exceed our “dump saturation” limit: 10,000 events allowed per 1-minute dump. Rest of events apparently thrown out at some stage.
        • actual event rate was not so high. Elevated trigger rate probably due to multi-DCRC retriggering and noise.
    • n,gamma coincidence run prep:
      • Run Si HV#4
        • use reduced shunt resistances. (Should replace the SQUET with the possibly “damaged” SQUID, will need to rewirebond one)
        • bare Am source to calibrate. What position?
      • Availability of PuBe source: we will wait until Vlad Pribiag is finished. Last lab is April 30
        • start run next week, configure/calibrate detector for a few weeks, also work on shield/source configuration
      • Planning to leave out 4K heat sinking
      • projected threshold of 18 eVee
      • continue to work on determining optimal source position from sims
  • Lab infrastructure
    • He-3 circulation pumps
      • still need to send back-up He-3 pump to Oerlikon/Leybold for service/repair
  • Processing and Analysis
    • Run 65 (Si 150mm 5Q 1/2-vacuum-interface)
      • 150 mm paper v2 complete. Author list?: Overleaf
      • Radial decrease: COMSOL model?
    • LIPs search - planning to use Run 66 data, best GeHV data.
    • Need to start Phonon Collection Efficiency paper (HV2, HV4, iZIP pathfinder)
    • Run 62 (HV#4, Si)
      • planning to work on low-energy calibration, in prep for Run 67
    • Run 63 (Ge iZIP pathfinder)
      • need to analyze Cf data
  • Old/continuing items:
    • exploring ideas for improvements without upgrade: float DCRCs for symmetric biasing Proposed Scheme, decrease Rshunt in SQUETs (had a look at this, a little hard to set up: SQUET picture), sidewall sources?
    • Run 62 (HV#4, Si) post-mortem: two “bad” channels seem not to be wiring problems, maybe the problem is on the detector (photos)
    • Run 60, 6“ detector paper
    • Lab infrastructure
      • plans to try to improve helium recovery
        • add length of copper tubing to recovery line, to warm helium on the way to the meter. We have used it and it seems to do something. But no indication yet that it is improving recovery.
        • maybe try to recover helium while waiting for the transfer stick to cool before hookup
      • Update on He recovery efficiency, slow transfer test
      • DAQ and data pipe
      • DAQ upgrade - discussed with Bruno about IbIs tool development
      • Data storage and backup:
        • Need to copy all Run 60 and some Run 61 data to SLAC
      • Autoprocessing and data organization development:
        • currently autoprocessing suspended, no “official” processing for Runs 60, 61, 62
        • clean up database - some info missing. Consider adding additional info
    • Possible plan to modify DCRCs (resistor swap) so we can increase front-end gain, improve IbIs (suggestion from Bruno)
    • IF (not likely) new DCRC RevC.2 arriving from Bruce in Denver then
      • missing resistors on 3 QET channels, we've ordered some