RC Meeting and Run Plan, Wednesday, February 12th 2020

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RC Meeting Information

RC Daily Meetings are at 4:15 PM, 2nd floor Counting House Meeting Room

Wednesday 12th Feb. 2020.

  • Owl shift: running on ref cell with unpolarized beam. 7am: beam down for restoring polarization and then pass change for Hall B (5 to 1 pass). Plan is to do Moller and then either production if the 3He cell is polarized enough, or more ref. cell runs.

General updates

  • Around 8 pm, Feb 11th, 2020 oven leak was fixed and hall was closed up for the beam permit. [1]
  • Following the long beam checkout procedure, started to take data with unpolarized beam on reference cell with ~ 20uA.
    • MCC wasn't able to send stable 30 uA beam over the half of the owl shift. Fixed after MCC tuned the cavities.
  • Beam is gone at 7:30 am to restore longitudinally polarized beam. Continuing with Moeller measurement after polarized beam restored.

Pending problem

Fixed problem

Recent polarization measurements

Current Run Plan

  1. Owl shift: ran on ref cell with unpolarized beam:
    • Empty Ref. cell (pump to empty). done
  2. 7am: *unpolarized beam is terminated. Polarized beam is restored. done
  3. 7am-8am: *Set momenta to SHMS=-3.4 GeV, HMS=-3.5 GeV set
  4. 11:25am, when polarized beam is back: Moller measurement. ongoing
  5. When Moller is done (mid to late day shift)
    • if both beam and target polarizations are adequate:
      • do short beam checkout. [7]
      • restore production data taking.
    • If not
      • do short beam checkout. [8]
      • Take ref. cells data at -3.4GeV/-3.5 GeV SHMS/HMS momenta:
      • Ref. cell should be empty, if not pump cell to empty
        • Take 2h beam-on time of Ref. Cell empty runs at -3.4/-3.5 GeV with 30 uA.(charge goal of 200mC).
      • 0.3h Fill with 145 PSIA (10atm) of N2.
        • Take 40min beam-on time of Ref. Cell N2 runs at -3.4/-3.5 GeV with 30 uA. (charge goal: 67mC).
      • Vent the ref. cell and then fill with 145 PSIA (10atm) of H2.
        • Take 2h beam-on time of Ref. Cell H2 runs at -3.4/-3.5 GeV. (charge goal 200mC).
      • 1h beam-on time (100mC charge goal) on "Carbon Optics" (not Carbon Foil, not Carbon Hole), 40uA with raster 0.5mm diameter.
      • Restore raster size to 4mm.
      • Change the spectrometer settings to SHMS=-2.6 GeV, HMS=-2.9 GeV
      • Take ref. cells data at -2.6GeV/-2.9 GeV SHMS/HMS momenta:
      • Ref. cell should be filled with H2 from the previous setting.
        • Take 1.0h beam-on time of Ref. Cell H2 runs at -2.6GeV/-2.9 GeV with 30uA.(charge goal of 100mC).
      • Vent and pump the cell to empty.
        • Take 0.5h beam-on time of Ref. Cell empty runs at -2.6GeV/-2.9 GeV with 30 uA.(charge goal: 50mC).
      • Fill the reference cell with 145 PSIA (10atm) of N2
        • Take 40-min beam-on time of Ref. Cell N2 at -2.6GeV/-2.9 GeV. (charge goal 67mC).
      • 0.5h beam-on time (50mC charge goal) on "Carbon Optics" (not Carbon Foil, not Carbon Hole), 40uA with raster 0.5mm diameter.
      • Restore raster size to 4mm. (unless the next step is taking Optics (sieve in) runs)
    • Execute the plan below only if target is still not polarized enough
      • Take Optics (sieve in) runs [9]
      • note the trigger change here to ELCLEAN


  • If beam goes away for more than 2h, or if during the downtime, MCC does operations that may change the beam tuning (except work on transport magnets), then do beam recovery procedure (do YAG viewer part only if your are suspicious of the harp scan results)
  • Make sure all the beam specs are followed (e.g. no raster size below 4mm on 3He cell).
  • Always take 120Hz of EDTM
  • Fill BTA with realistic numbers. You may follow the guidance coming from "load from EPICS", if it does not overestimate the ABU (as it generally does).
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!                                                     !!
!!  ATTN: SHIFT LEADERS                                !!
!!     Please follow the shift summary template on     !!
!!     the laminated SL instructions.                  !!
!!                                                     !!
!!  ATTN: TARGET OPERATORS                             !!
!!  All NMR measurement HCLOG entries should include:  !!
!!     1) A title that clearly lists polarization      !!
!!     2) Screenshots of both NMR_FieldSweep and       !!
!!        the polarization fit                         !!
!!                                                     !!
!!     For an example see the following entry:         !!
!!     https://logbooks.jlab.org/entry/3768696       !!
!!                                                     !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Future

  • General idea: if target polarization is about equal for transverse vs. longitudinal, alternate 4 hours of transverse and 20 hours of longitudinal data taking. Do NMR before and after transverse, and every 5 hours during longitudinal.
  • Production at 30 degrees. We may want to start from HMS/SHMS=-2.9/-2.6 momentum setting, complete this and then go back to HMS/SHMS=-3.5/-3.4 momentum.

Hall Access

  • The next possible hall access is on Friday, Feb 14th, 2020 when the Wien angle change is scheduled by the accelerator.
    • Target work.
    • Hall C safety walkthrough (4 people)
    • Testing & installation of the spare rotation stage by Ethan and Brad. [10]
    • Power supply swap - replace Agilient with new Kepco.

When there is a down:

Notices in Effect for Shift Crew

  • 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 SHMS dipole trips again, take a screenshot of the PSU window 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.
  • The operators have been somewhat careful with our beam orbit locks. 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[11]
  • Temporary Laser instructions can be found here [12]
  • Do not change SHMS momentum until we fixed the current lead valve

Planned Accelerator Configuration Changes

  • Bluejeans remote connection information:
 To join the Meeting:
 https://bluejeans.com/861439920
 To join via Room System:
 Video Conferencing System: bjn.vc -or-199.48.152.152
 Meeting ID : 861439920
 To join via phone :
 1)  Dial:
   +1.408.740.7256 (US (San Jose))
   +1.888.240.2560 (US Toll Free))
   +1.408.317.9253 (US (Primary, San Jose))
   (see all numbers - http://bluejeans.com/numbers)
 2)  Enter Conference ID : 861439920

Useful Links

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