RC Meeting, Tuesday, Dec 14, 2021

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RC Meeting Information

   Have RC meeting today

RC Daily Meetings are at 10 AM, remote

  • 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

Current Status

Current RC: Dave Gaskell

On Owl shift, completed deuterium data taking for LD2, pi+ Q2 =6.00 GeV2, W=2.40 GeV, x=0.55, low epsilon, right. Total pions = 17,797 (out of 23,000 from original projections): https://logbooks.jlab.org/entry/3962573

Switched to LH2 at ~ 4 am. pi+ rate about the same: ~ 700 pions/hour (1493 pions after 1st 2 runs).

Future plans

  • Continue production data at 70 uA on LH2 (SHMS right) - expect to switch to SHMS center tomorrow on DAY shift
  • Checked with Steve about moving to 6.16 degrees on Dec 20th. This can be done with remote oversight.
    • Need to be sure that the Gui angle is modified to agree with the true angle when at 8.16 deg.

Current Run Plan

We are currently on (Ebeam=8.0 GeV) Q2=6.00, W=2.40, x=0.55, low ε data taking – PART TWO [See run plan]

  • Target: LH2

Q2=6.00 GeV2, W=2.40 GeV, x=0.55, low epsilon, HMS angle=34.58deg, HMS momentum = -2.139 GeV/c SHMS angle= 9.12deg (right), SHMS momentum= 5.512 GeV/c

  • Controlled access today during injector test plan. Expect hall to be open by 10 am. Planned work includes:
    • Steven L. will check rotation encoders
    • Hall C techs will pump on LN2 transfer line, clean encoder wheel
    • Tests of the raster gui (doesn't need hall access, but will be done while beam is away). Need to make sure the raster is in a good configuration before beam is back.
    • Heidi will check a few spectrometer cryo-related things
    • Joe Beaufait will conduct a Hall C walk-through

Notices in Effect for Shift Crew

  • The Raster Coil pair Ax and Ay are off. Raster needs to be at 4x4. Raster gui has been updated - can now request 2x2.
  • With LHe alarms it is good to check the cameras for plumes. If no plume and it is below the LO alarm and above LOLO then monitor with a plot and halog the problem.
  • With LNitrogen alarms are not that critical. Just need to start monitoring the problem with plot and Halog.

Current Issues

  • There is a rotation issue that has come up if moving HMS between 19 to 25 degrees. It usually gets stuck around this range, please be wary of this issue. We will likely skip settings in this range if this drive controller error cannot be solved. For singles it will not be a big deal to skip settings for HMS at those angles. We need a longer access to address this issue (cannot be done on Tuesday 12/14)
    • SHMS cannot be rotated to angles > 30 degrees - the proximity switch has either moved or was accidentally set in the wrong place. Not an issue for now - will be addressed before we restart in January,
  • The Raster Coil pair Ax and Ay are off
  • Diffuser limit at 46uA (Note: is this still valid?)


Crew Chiefs, We have permission to raise the Hall C diffuser raster limit to allow running >46uA to Hall C. This limit is normally imposed when one of the two rasters is not operative. Since the hall was able to double the running raster current to get the same size raster on the target as having both rasters, Keith is allowing us to raise the limit. To get to the setting, open the Hall C diffuser interlocks screen. Go to the bottom right corner and open the Expert screen. Just below and to the right of the FSD bits, raise the "Raster 1 OK Limit" to slightly above the highest current the hall wants to run at. Do not change the Raster 2 limit. Make a log entry with screen shots. Make an ABIL entry, System MPS and an expected removal date of 3 Jan. 2022. Paul

Planned Accesses to the Hall

  • OPS Beam injector test tomorrow Tuesday (12/14) scheduled 9 AM- 1 PM (no beam during this time)
  • See above for planned work.

Planned Accelerator Configuration Changes

  • none

Special Requests

  • none
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