Pol He3 Target Meeting May 18, 2020

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


  • Several discrepancies within the datasets for AFP loss for each cell were found and are being scrutinized
  • Will place an order for the spectro-analyzer for transverse laser monitoring once a quote is received
  • Ordered 3 new lasers during A1n running, whose wavelengths are controlled via software as opposed to a dial like on the previously-used lasers. Raytum has sent us an update on the Labview software so that we’re able to use it
    • Need to be certain if this will cause an issue for EPICS logging
  • Please make a summary of unique cases of Labview crashing during data-taking and the different steps taken to resolve them


  • Got all the data needed from the Survey Group. Will put together a document summarizing Compass measurements and final results


  • Assisting Jixie with the field mapping report


  • We should get a 2-week notice before people are expected to be on-site again at Jefferson Lab, and then we anticipate another 2 weeks after that for operations to begin
    • the earliest for on-site target support would be the first/second week of June with the earliest possible beginning of beam operations the last week of June/1st week of July
  • Should have 6 weeks of running, but we are still unaware of a hard cut-off date in the fall

We are going to have to write up an OPS for any task that requires two people to be within 6 feet of each other, and then it’ll need to collect signatures up to Rolf’s level. This includes, as a start:

    • Laser alignment
    • Cell mounting
    • Removing/installing the target enclosure panels
  • Software from the target lab (ex. to control the new lasers) shouldn’t be mixed with what’s in the counting house
    • worst-case scenario is that if there’s write-access to pertinent PVs and somebody does work in the target lab during production, garbage data could be leaked into real data
  • EPICS integration with current lasers needs to be ready to go as soon as the target experts return on-site to begin re-commissioning work


  • We need to review needed instrumentation for all polarimetry and place orders ASAP
  • The overall plan is to test the current cell Austin in all configurations and get all the calibration constants before beam is sent
    • could easily take a week since each spin-up takes a day


  • The new KEPCO power supply was delivered to JLab


  • Need only a handful of days (~ a week) to complete density tests for Tommy and Butterball
    • window thickness measurements already completed


  • Make sure we have all the needed supplies for cell mounting, and to have another cell on standby ready for replacement

We expect presentations from Junhao and Mingyu next week (May 25th), and a presentation on Jixie’s field mapping results the following week (June 1st)