RC Update and Run Plan, for Saturday, March 7, 2020

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RC Meeting Information

RC Daily Meetings are M-F at 4:15 PM, 2nd floor Counting House Meeting Room Bluejeans Connection

Saturday March 7, 2020.

General updates:

  • Once we got going again Friday after accelerator issues and Moeller, took HMS/SHMS -3.5/-3.4 GeV data with 3He target, longitudinal polarization. Good production for remainder of Fri swing and Saturday owl.
  • Saturday day shift, the SHMS dipole PS started tripping repeatedly. Continued taking data with HMS of course, but beam trippy and less than 30 muA.
  • Switched to transverse target polarization and took production data with HMS only. In parallel, Steve L tried a software fix for the SHMS dipole PS, but no joy.
  • We were at the point of giving up on the SHMS for the weekend, when Jack S offered to bypass a relay in the PS. He was in the hall only 40min and the SHMS magnets are set. https://logbooks.jlab.org/entry/3799371
  • The target polarization was switched back to longitudinal at the end of day shift. There was some confusion about this in the pass-down to the next shift, but the hclog documentation has been cleaned up. We're ba-a-a-ckkkkk in longitudinal production HMS/SHMS -3.5/-3.4 GeV data with 3He target. Thanks to Steve L, Eric S, and Jack S for spending a chunk of an otherwise very fine Saturday on the SHMS power supply issue.
  • Four target polarization measurements since restoration yesterday: 55.6%, 55%, 55.1%, and 54.2% (this last being transverse).

Current Run Plan:

Saturday

  • DONE! Sometime in late owl/early Day shift, after one scheduled NMR measurement (in longitudinal), rotate target to transverse (90 deg, rotation by expert only).
  • DONE! Take 5 hours of transverse production data there.
  • DONE! Upon completion, do one NMR in the transverse direction, then rotate target to longitudinal (180 deg, rotation by expert only).
  • ONGOING Resume longitudinal production data taking with target at 180 deg, take NMR every 5 hours.

Sunday: continue longitudinal running with NMR every 5 hours. I'll let you know Sunday morning when to switch to transverse.


Notes for the Future

  • 'Filler' runs for next spin up / target-down period (Don't want to forget about this!):
    • 1 hour run with target out for measure of the background just from the beryllium windows. (Needs SHMS, btw.)

Pending Issues

  • pNMR issues
    • Software/driver issue needs to be resolved
    • Checkout during next non-production down time (Moller or SHMS fix)
  • EPR problems [1] saw some progress on Tuesday [2], but issues remain
    • Tentative plan now is to continue the d2n (and A1n) program by replacing the photo-diode that is placed directly on the pumping chamber (we have many spares)
    • It would be good to write up a procedure to streamline this replacement procedure for us and RadCon
  • Kepco power supply commissioning/installation (Todd, Bill)
    • Bill will update status on Thursday
  • Verify that calibration constants and input values associated with NMR and other polarimetry are consistent and will be correct when the software is restarted [3] [4] [5] [6] [7] (Bill, Junhao)
  • Persistent BLM & ion chamber trips
    • General activation, weird BLM issues (https://logbooks.jlab.org/entry/3792326), Ad-hoc ion chamber threshold adjustments (https://logbooks.jlab.org/entry/3792095)
    • NOTE: Shift crew should NOT give authorization to MCC change ion chamber thresholds. If they ask, tell Operator to contact an appropriate expert. Make a log entry if trips persist, or call the RC if it becomes severe (for example, >20 trips/hour is getting intolerable)
    • Beam Studies program will investigate some of these issues (most pressing is significant activation + beam loss in the arcs)
  • Contact with Target readbacks through AnywhereUSB USB bridge still drop out on occasion
    • Initial replacement of the USB bridge failed (did not seem to help underlying issue, then bridge stopped working), replaced with original device
  • OPs wished to reboot hung iochc10 [8], noted in December as well [9]
    • This runs the Moller cryo controls and should not be rebooted without expert oversight (does not impact operations). D. Gaskell is looking into getting this addressed properly with OPs.

Opportunistic Access Jobs

None at the moment.


Standing Orders

 If beam goes away for more than 2h, or if during the downtime, MCC does operations
 that may change the beam tuning, then do [https://hallcweb.jlab.or/wiki/index.php/Beam_and_Raster_Checkout_for_A1n/d2n_(Short_Procedure)
 beam recovery procedure] (do YAG viewer part only if you are suspicious of
 the harp scan results)
  • NOTE: Shift crew should NOT give authorization to MCC change ion chamber thresholds. If they ask, tell the Operator to contact an appropriate expert. Make a log entry if trips persist, or call the RC if it becomes severe (for example, >20 trips/hour is getting intolerable)
  • Check the position locks are on.
  • Do your best to accommodate Hall A's request for a PITA scan promptly. It is OK to stop the present runs and start new ones in 5--10 minutes after they are done.
  • Check that 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       !!
!!                                                     !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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 any magnet trips, snapshot the associated power supply window and post it to hclog before resetting the interlock.
  • Monitor the beam position on target and call MCC immediately if you see large excursions (1 mm level).
  • Ramp rate lock instructions are here and added to checklist[10]

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


Target coil rotation planned for March 13--20

  • Nominal 1-week downtime in Hall C to rotate target coils, install new cell, and transition to d2n program

Useful Links

Target Polarization Angle Conventions

Be VERY clear here about the convention (beam-right/left/up/downstream) vs 0, 90, 180, 270)
for each run period.  More notes and references to log entries are better.

Polarization Calibration Data

ADD LIST OF CALIBRATION RUNS HERE
AND A TABLE OF RELEVANT CALIBRATION CONSTANTS TO USE FOR WHAT RUNS
Cell Calibration
Type
SHMS Angle
/degree
SHMS Momentum
/GeV
Field Direction
/degree
Calibration Results Status Oven Temperature
/°C
Log#
Tommy EPR-NMR 11 7.5 90 5.24 %/mV Done 200 3839939
Tommy EPR-NMR 18 5.6 270 5.04(1) %/mV Done 205 3843301
Tommy EPR-NMR 18 5.6 90 undone 205
Tommy EPR-NMR 11 7.5 270 undone 208
Tommy AFP Loss 14.5 6.4 90 1.25%/Sweep Done 200 3840618, 3840143, 3840618
Tommy EPR Amplifier
on/off NMR Signal
11 7.5 90 Done 200 3839962
Tommy Temperature Test 18 5.6 90 Done 205 3844089
Tommy AFP Loss 18 5.6 270 Done 205 3845255
Tommy Temperature Test 18 5.6 270 Done 205 3845336
Briana EPR-NMR 18 5.6 180 8.60 Done 205 3834036, 3834243
Briana EPR-NMR 18 5.6 270 5.6 Done 205 3835512, 3835587
Austin EPR-NMR 18 5.6 90 4.88 Done 200 3814717
Austin EPR-NMR 11 7.5 180 7.64 Done 210 3817200
Austin EPR-NMR 11 7.5 0 8.13 Done 210 3818761
Austin EPR-NMR 11 7.5 270 4.56 Done 210 3819882
Austin EPR-NMR 11 7.5 270 4.58 Done 210 3822296
Austin EPR-NMR 11 7.5 90 4.91 Done 210 3824907
Austin EPR-NMR 18 0 90 4.58 Done 210 3815895
Austin EPR-NMR 11 0 180 6.91 Done 210 3816724

Target Polarization Database

d2n Run Period

D2n Target Run List: https://docs.google.com/spreadsheets/d/16TrIUXVA-znVNUyEKy9FHaIlcvq-KXzu97k9nJowuE8/edit#gid=0

  • Junhao Chen is maintaining it

A1n Run Period

https://docs.google.com/spreadsheets/d/e/2PACX-1vSoTyDugD8wt3hKmBGZBxwUJTPHmUgyvGVJvM7N6qeVoNWhEXumCwwkPI7Sw9Asae3N4k9h5L0Y7qmw/pubhtml

  • Mingyu Chen will updating the runlist while Murchhana Roy will do the cross check.

Recent polarization measurements

PolHe3 Polarization Measurements






Misc Links