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Note: this connection info is for this meeting only
Teleconference link: https://umn.zoom.us/my/fritts
Domestic: 1-646-558-8656 (US toll)
Domestic: 1-408-638-0968 (US toll)
Access code: 8797896096
  • Lab Update
    • Source mover performance
      • We can send any number of steps to the motor without the coil resistance going up
      • Heating is still significant
      • Can move 6 mm/hour and fridge remains stable (c/w 1 mm/hour in Run71). At this rate the average heating seems to be around 100 μW.
      • We've tried as high as 13 mm/hour but above 9 mm/hour the fridge can't keep up - not sure what would happen if we did that for more than a few mm
    • ~3 kHz noise
      • A couple of charge channels showed high noise with pickup in the others, too high to see 60keV line
      • As of last week this noise is 10x smaller - so we can take meaningful data again (if it doesn't come back)
    • Identifying source position
      • After motor rebuild we don't know which direction is which.
      • Moved far enough to reach near endstop - didn't see contact so moved far enough to reach far endstop - still didn't see contact…
      • Verified we were at endstop by seeing that temperature spikes weren't as high after the source mover was stopped
      • Moved source to the opposite endstop, and saw contact (apparently only one of the endstop wires is connected). Not sure which one it is…
      • Under the assumption source was at near endstop, we took data. Data indicates source is above q3, the first ring out from the center.
        • this makes sense if the source was near the far endstop before the move
      • Under the opposite assumption, we've now moved source to center and will try to repeat previous data
  • General Updates