UMN CDMS Wiki archive
start › cdms › k100 › meetings › 20180308

Agenda

  • Operations
    • Run 67 (re-run of USD1)
      • During LN2 transfer, fridge developed a blockage - had to warm up.
      • Also saw a short from the FET gate to chassis on the inner channel, not present at 300 K but present at 77K (around 1 MOhm). Remove tower to fix this
      • Second cooldown - good fridge throughput. Short to chassis reappeared at 77K again, but smaller (around 60 MOhm). Decided to proceed.
      • Another problem - difficult cooldown. Hard to keep 1K Pot from running dry.
        • originally thought it was a slow-cooling detector
        • now wondering if it's excessive He in IVC. There was evidence of a leak from bath to IVC after we cooled to 77K.
      • Took some data at 4K. (Noticed that the crystal becomes insulating at around 15 K.) Can we run at 4K?
      • Proposed charge relative calibration measurement : test signal on bias electrode
    • n,gamma coincidence run prep:
      • Run Si HV#4
        • use reduced shunt resistances. (Should we replace the SQUET with the “damaged” SQUID?)
        • bare Am source to calibrate. What position?
      • Availability of PuBe source: we will wait until Vlad Pribiag is finished. Last lab is April 30
        • so start run around April 1, configure detector for ~1 month, then begin using source
      • do we understand the n-flux? will it be high enough?
      • Planning to leave out 4K heat sinking
      • projected threshold of 18 eVee
  • 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
      • cce models
      • 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