RC Meeting and Run Plan, Friday, February 21st 2020

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RC Meeting Information

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

Friday 21st Feb. 2020.

General updates

  • Smooth running until we stopped to deal with HMS Q3 ice at 13:15
  • ESR compressor crash at 13:51. Lost all magnets. https://logbooks.jlab.org/entry/3788275
  • HMS Q3 JT repaired, tarps set up to divert meltwater away from target and its electronics. SHMS xfer line IV pumped on. Kepco ps removed from hall after radcon cleared it.
  • Did energy calibration while waiting for ESR to recover
  • Did BCM calibration while waiting for ESR to recover
  • Did beam recovery harp scans
  • Started HMS data ~ 11 PM Thu, SHMS took another 1 1/2h to cool down (HB), then took data with both arms
  • Made escorted access today ~2 PM to push water away from above laser box see https://logbooks.jlab.org/entry/3788855

Pending problems

  • 3 hour stand-down Wed AM. Can we count on cryo support then to cool down Moller to make a Moller msrmnt Thursday?
  • Locks and energy was changed. I don't understand this- have asked Jay to come and explain it to us. See https://logbooks.jlab.org/entry/3788977 and https://logbooks.jlab.org/entry/3789011
  • Locks on vertical beam position have not been working see https://logbooks.jlab.org/entry/3788540. Have made a point with the PD this AM that this has to be understood and corrected as soon as possible- it's a huge safety concern for us.
  • Small changes in beam position have been deliberately made as well while we are at 30 uA on 3He (see https://logbooks.jlab.org/entry/3788864)
  • online monitor broke, was fixed by Whit
  • Raster energy alarm, possible cause: it's initialized for 10.43 GeV not 10.383 GeV.
    • The working hypothesis is that the mismatch between the raster GUI energy (10.43 GeV) and the Tiefenbach energy (10.386 GeV) is the reason for our nuisance alarms. I told him I was skeptical of this explanation, and thought it was probably transients, but what the hell, why not change the raster GUI energy the 1/2% to match the actual beam energy anyway. I had to go back to the counting room to give him the process variable name (ecEHCFRHALLC:p). But I noticed that the alarm limits on this are 10 times tighter than the 0.044 GeV actual difference between 10.43 and 10.386 GeV. So it should alarm all the time if that's the problem. And then we had a raster energy alarm while we were looking at the GUI, and the reason was that this PV was "inf", ie it was a readout transient, not a real issue. The crew chief said he'd talk to software about changing the raster energy anyway, and look also for a less noisy PV to use for energy.
    • Brad made some improvements, see https://logbooks.jlab.org/entry/3788240
  • Harp travel problem can't be fixed without taking the harps down (out). Limit switch is already at end of clearance. Way bigger job than we thought (so punt).

Not sure if it is a problem

Fixed problems

Opportunistic Problems to get done at some point

  • Note there may need to be a recesiation of the photocathode in 10-14 d which could take 10-12 h, according to what Joe Grames said at Wednesday's 1:30 meeting. See https://logbooks.jlab.org/entry/3788008
    • The injector group may just move the spot- it remains to be seen.
    • This could be checked when we go down for 4 h iTuesday to fix a PSS problem with the lasers in the injector

Opportunistic Access Jobs

  • Walter would like to pump out some of the insulating vacuum lines (needs ~4-5 h). Note that the SHMS xfer line IV was done today during the ESR crash- still need to do the HMS. Actually he also wants to do more on the SHMS too.
  • Need also to pump out the Moller magnet IV, see https://logbooks.jlab.org/entry/3788801
  • NOTE: 4 h access tentatively possible Tuesday morning (injector laser PSS)

Recent polarization measurements

Current Run Plan

  • Taking production data with 3He. Stay in longitudinal until further notice. NMR every 5 hrs.
  • Next Moller measurement next week sometime.
  • Momentum change likely this weekend
  • 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)
  • Check the position locks are on.
  • Check CODA is running normally (had one strange hangup lately)
  • CHeck online replays shortly after starting runs, & full replay results too.
  • 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. If we have to lower the beam current we actually want because the beam is too unstable, prorate the ABUs.


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!                                                     !!
!!  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

  • We will return to the 3.4/3.5 GeV spectrometer momentum settings (angles stay the same) sometime this weekend probably, to get more stats there once we get enough at the higher rate setting we're at now.
  • The transition to d2n will probably happen sometime the week of March 9-13.
  • For the time being we will run exclusively with longitudinal polarization. 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 (maybe) eventually 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.
  • 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

  • Note there will likely be a recesiation of the photocathode in 10-14 d which could take 10-12 h, according to what Joe Grames reported at the 2/19 1:30 meeting.
    • The injector group may just move the spot- it remains to be seen.
    • This could be checked when we go down for 2-3 h in the next few days to fix a PSS problem with the lasers in the injector
  • Bluejeans remote connection information:
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 Meeting ID : 861439920
 To join via phone :
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 2)  Enter Conference ID : 861439920

Useful Links

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