Pol He3 Target Meeting May 11, 2020

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

Jian-ping

• We need to think of things that to be done to prepare for d2n running once the lab reopens, and add it to the “punch list”: https://hallcweb.jlab.org/wiki/index.php/PolHe3_Punch_List_For_Restart.
• We'll discuss it in detail next week as a group

Junhao

• Working on the temperature test data and remaining AFP loss studies (it varies so much with changing conditions, there's still a lot of work to do)
  • Will present an update next week
• We need to be able to remotely monitor the spectro-analyzer in the transverse direction, since it’s especially important for d2n. We already have a fiber for it and in the process of getting a quote for another spectro-analyzer

Murchhana

• Emailed Chris regarding the uncertainties in the survey coordinates. He said the uncertainties for the points on the beamline (where the compass is located) is +/- 0.28 mm and +/- 0.5 mm for the mapper points

Christopher

• Currently holding onto new cells Butterball and Tommy for wall thickness measurements and some spectroscopy. Can do all of that before JLab is ready for the cells

Melanie

• Presented two methods used to determine statistical uncertainties on the frequency shifts in the EPR analyses
  • Method used in Xiaochao's thesis is the correct one, since the error shouldn't grow with the number of measurements performed
• Will write a short simulation to replicate the data points as a brute-force method to extract the uncertainties as a cross-check, as per Brad's suggestion
• The systematic uncertainties need to be studied carefully for cases where the field was unstable, the cell was pumping up, etc. like the case for Big Brother on 2/13 right after the cell-swap