Revision as of 15:27, 18 February 2020

RC Meeting Information

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

Tuesday 18th Feb. 2020.

General updates

• Accelerator was down for the Wien flip between 8:30am on Monday and ~4:30am on Tuesday.
  • • A nice post about the Wien flip (https://logbooks.jlab.org/entry/3786542)
  • Opportunistic access during that time for the target work.
    • Rotation stages and camera were installed in the laser optics box.
    • Mounted the longitudinal QWPs to the rotation stages.
    • Added fibers to the laser spectrometer --> longitudinal and transverse spectrometer signal can be separated by disconnecting corresponding fibers (https://logbooks.jlab.org/entry/3786230).
  • After hall work, longitudinal QWP angle optimization by Murchanna and Bill (ongoing). (https://logbooks.jlab.org/entry/3786342 )
• MCC meeting: problems to send desired current to Hall A and C.
  • Injector matching at 5 MeV and injector to North Linac (done between 8:30 am and 12:40 pm today).
• Back to production running with longitudinal spin direction.

Pending problem

• Fluctuating SHMS Q1 LN2 levels since February 14th: https://logbooks.jlab.org/entry/3785541
• Ion chamber trip thresholds manipulation by MCC: https://logbooks.jlab.org/entry/3785352 https://logbooks.jlab.org/entry/3783965 https://logbooks.jlab.org/entry/3784607
• Fluctuating beam positions: https://logbooks.jlab.org/entry/3785492. Orbit locks are suspended until a certain current value is reached (very big values indeed!). A deal can be made with MCC about this.
• Raster energy alarm, possible cause: it's initialized for 10.43 GeV not 10.383 GeV. Ask MCC to initialize with the correct beam energy?

Not sure if it is a problem

• HMS Dipole interlock during Saturday owl shift: it's not known if a specific problem on dipole triggered the interlock but reset was successful.
• TO of the Monday owl shift reported an issue with the field correction coil readback which has been causing alarms: https://logbooks.jlab.org/entry/3785664 https://logbooks.jlab.org/entry/3786238
• Large drops and increases in SHMS Q1 LN2 levels since February 14th: https://logbooks.jlab.org/entry/3785541. Seems to be better https://logbooks.jlab.org/entry/3786755

Fixed problem

Recent polarization measurements

• longitudinal polarization measurements after yesterday's target work in the hall and QWP angle optimization
  • 39.4% // : https://logbooks.jlab.org/entry/3786300
  • 49.5% // : https://logbooks.jlab.org/entry/3786537
  • 47% : https://logbooks.jlab.org/entry/3786686

Current Run Plan

• When the beam is back follow the beam checkout procedure.
• While you're asking MCC to turn the raster on with the suggested diameter (after harp scans), ask them to initialize the raster with correct beam energy.
• Make sure we're able to get "good" 30 uA and then start taking production data.
• Moeller measurement is scheduled for Wednesday morning.

• If beam goes away for more than 2h, or if during the downtime, MCC does operations that may change then beam tuning (except work on transport magnets), then do beam recovery procedure (do YAG viewer part only if you 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). https://logbooks.jlab.org/entry/3783171

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!                                                     !!
!!  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.

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.
  • Good examples for entering and leaving laser 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[1]
• Temporary Laser instructions can be found here [2]
• 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

• Main Pol He-3 wiki
• Shift Schedule
• Hall-C Controls
• Hall-C Logbook
• MCC White Board