RC Update and Run Plan for Aug 15, 2020

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RC Meeting Information

RC Daily Meetings are at 4:15 PM, remote

Wednesday Aug 15 2020.

General updates

  • Hall A was able to run over night without using the Moller quads and after work this morning, appear to have the Moller quads back up and running.
  • So we will stay with the original plan to make the change to 1st pass on Monday August 24 and return to 5th on Thursday August 27.
  • Just a reminder when thinking about when to change the target cell.
  • QPM Transverse LEFT and RIGHT were optimized during Friday DAY and SWING shift: Transverse_RIGHT,Transverse_LEFT
  • Polarization increased afterwards from ~40% to ~42%, and has been fairly steady at in the 42% range


Pending problem(s) / Things to track

  • Lost Pumping chamber RTD1 during target homing: https://logbooks.jlab.org/entry/3828350
  • Target related studies at 90deg
    • Compete a temperature curve study
      • Should plan for a 4--6 hour spin-up after this test (do this after Moller)
    • Pulse NMR tests (will impact polarization, so need to plan correctly)
  • Schedule a Moller for mid next week (Thurs?)
    • Plan the temp curve study and spin-rotation to longitudinal around this as well
    • Can take remaining ref cell data after Moller during spin-up too
  • Analysis related things
    • Confirm that Analysis group is sanity checking the electron yields vs predictions as well as delivered charge -- Possible update tomorrow?
  • Please keep an eye on when the IHWP was last changed. It should change every 8 hours (or so)
    • Do not want it going much too much beyond this -- politely remind Hall A SL at the 8 hour mark
  • Follow-up on HMS Dipole NMR setpoint issue [1] (Steve Wood, Steve Lassiter)

Recent polarization measurements

  • NMR measurements taken recently after the QWP optimization
  • Transverse @ 90 degrees (12:08): 42.1% -NMR_DAY
  • Transverse @ 90 degrees (07:09): 42.0%----NMR_OWL_2
  • Transverse @ 90 degrees (02:00): 42.6 % ---- NMR_OWL_1

Current Run Plan

Normal Production running

  • Prerequisites
    • Make sure the raster size is correct (4--4.5mm)
    • Monitor beam parameters/configuration very often and post an entry like this at the beginning of your shift and when run conditions have changed
    • Running on cell targets: raster always ON (4--4.5mm, size will be determined by the scraping checks), orbit locks ON, current ramp rate 1 muA/sec
    • Always take 120Hz of EDTM
    • Fill the BTA with realistic numbers. If the desired beam current is not delivered prorate your ABUs!
    • Change the IHWP at least every 8 hours when running on glass cells. If Hall A hasn't changed in 8 hours, call the RC
  • Run plan
    • Continue taking production data on the polarized Helium-3 target. If not able to reach requested current, pro-rate the ABUs

Notes for tomorrow's 9:00 am meeting

  • Beam stability / trip rate? ---- Has been somewhat better the past few days
  • Accel Maintenance RF-recovery day?
  • Steve Suhring was going to check on the voltage to Hall C when he could (as a follow-up from the Hall A issues) -- might need to wait until Monday, but can ask

Future

  • Please sign up for shifts next week (when the link works...) --- https://misportal.jlab.org/mis/physics/shiftSchedule/?experimentRunId=HALLC-POL3HE
  • There are several owl shifts starting the end of next week (I think)
  • We are on the schedule to switch to 1st pass on Monday (Aug 24) and switch back to 5th pass on Thursday (Aug 27).
  • Check the SAD calender for schedule updates (MCC white board isn't currently being updated)
  • Jay still has no set day for maintenance/beam studies for this upcoming week (or the following week): maybe a short Ray Trace beam studies (~ 1 hour)
  • The EPR diode was checked again on 08/15, and still appears fine. Continue periodic checks---- https://logbooks.jlab.org/entry/3827793

Hall Access

When there is a Down

  • If Hall will have opening for 1+ hours, let Simona know as there is work to do on the SOLID cerenkov.

Notices in Effect for Shift Crew

  • Beam positions: [2]
  • Policy for CANS-related hall status change: Make a logbook entry when the hall goes in, or comes out of laser-controlled access.
  • Magnet policies
    • Spectrometer GUI (go_magnets) should always be visible on Shift Leader computer, hcdesk3
    • HMS Q1 must be ramped down in 50A steps in all cases
    • Do not ramp HMS Q2 to zero, only go to 10A and then switch off power.
    • If any of the Spectrometers magnets trip, take a screenshot of the PSU window and check the hall for smoke or water with the camera before resetting the interlock and post it to hclog.
  • Inform the RC of any access that the Target Team requires. The RC will coordinate with RadCon to make everything run smoothly.
  • Please make sure that the orbit locks are enabled and the beam does not drift from its nominal position.
  • Ramp rate lock instructions are here and added to checklist[3]

Planned Accelerator Configuration Changes

  • Hall C to 1st pass on 8/24 and back to 5th pass on 8/27


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