Pol He3 Target Meeting April 20, 2020

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Members present: Jian-ping, Mingyu, Junhao, Brad, Murchana, Todd, Bill, and Jixie

Begin time: 1:30 p.m, End time: 2:14 p.m.


  • It would be good to identify which runs are calibration runs (EPR/NMR, AFP loss, etc.) and to prioritize those first
    • comment which are also problematic runs, good runs, junk runs, etc.
    • for production runs, include beam current. Need to know how the target polarization changes with the beam current
        • should usually be 30 uA of course, but there are times when MCC couldn’t deliver it that high, and would be more on the order of ~ 20 uA
  • considering calling into Bluejeans for better audio so we can hear better!


  • dv/dB expression I use in the polarization calculations is from Chiranjib Dutta’s Thesis is consistent with the second-order magnetic moment correction factor (Equations 1 and 2) from Babcock, et al.: https://pol3he.sites.wm.edu/wp-content/uploads/sites/50/2018/04/Babcock-EPR.pdf which claims the second-order correction is needed for 39K.
    • also consistent with what Todd and Sumudu are using for the k0 data, so we can trust my EPR polarization expression
  • Talk with Junhao offline about calibration equation used for different EPR/NMR calibration sequences/AFP loss scenarios


  • Go ahead with obtaining the new power supply in the event we can resume data-taking once the lab reopens. We want to be ready


  • Startup of lab is still unknown. But once it opens, there are two options:
    • Go ahead with the shutdown as planned (9 months of shutdown starting May 6th)
    • Resume data-taking!

For next week, we expect presentations from Junhao and Murchhana. The others will provide briefings.