Pol He3 Target Meeting March 30, 2020

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Members present: Jian-ping, Arun, Bill Henry, Murchhana, Mingyu, Todd, Melanie, Junhao, and Brad


  • Need to compile a report of lessons learned for the successful operation of the 3He target to be used for future polarized 3He target
    • send Jian-ping whatever points you have (whether it’s a few sentences or paragraphs; an informal setup is fine, with bullet points)
      • include topics like the power supplies for the field (ex. later realized we needed to reverse polarity to change the field direction)
    • please do it this week if possible
    • Gordon and Todd can send comments on the cell production portion
  • d2n
    • Should write down what we still need to do to prepare for d2n running and optimum target performance
      • ex. issues that need to be resolved regarding the field stability, strong polarization loss, downstream NMR in the TC has very broad peaks in the signal, issues with the transverse PC NMR signal (something wrong with the cabling between the preamplifiers and the pickup coils)
      • Poor Raytum D2 fiber performance for EPR; use another option?
      • Should make the transverse spectroanalyzer working in addition to the longitudinal channel that was used to optimize cell pumping during a1n (transverse orientation is more important for d2n)
      • we should keep a running list of this on the polhe3 wiki
    • Thia sent a message to Walter, JP, and Dave Meekins asking how long it would take to switch from polarized 3He running to regular cryogenic target running
  • Target Analysis
    • Want some kind of polarimetry database delineating the target conditions for each run/NMR measurement
      • all the EPR/NMR runs, transverse running, longitudinal running, which are bad runs, good runs, apply flags for classification, etc.
      • Mingyu will do this with Murchhana’s help to cross check
      • the spectrometer runs already exists via the online analysis tables
    • NMR/EPR calibration runs, NMR AFP loss and temperature studies, etc.
      • Junhao will do the NMR analysis
      • Melanie will do the EPR analysis
    • Ultimately need to apply the real target polarization to the production runs
  • Power Supply
    • Is the current one good enough? Or should we revert back to voltage-controlled instead of current controlled?
      • probably didn’t give the current mode power supply enough of a chance before switching back to voltage mode. Hard to say; Bill will summarize issues. Needs to be tested again


  • JLab’s Survey Group hasn’t responded yet. Will likely take a while for them to reply given the lab shutdown and transition to remote work
    • Brad suggests waiting a week to follow-up


  • Took data with Jixie’s field correction coil settings with 2 out of the 3 kinematic settings. Need to assess the runs to determine how well we can predict the correction settings for the third kinematic setting


  • Want pNMR working
    • Instrumentation is working with AFP loss at only 0.5%, just seems to be very sensitive to the field