RC Update and Run plan for Sep 14,2020

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RC Meeting Information

RC Daily Meetings are M-F at 4:15 PM 

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Monday 14 Sept 2020. 

Updates to this page are in progress

General updates

(See d2n Run Plan 2020 for broader status/overview.)

  • Smooth running once beam came back at 4pm yesterday
    • Took production in Kin-A, Kin-X in transverse/90 w/ triggers T1, T3 (and some T2)
    • Will likely switch to T2 triggers (EL_real) for rest of Kin-A, Kin-X running (confirm)
      • T2 and T3 cut out a fair bit of garbage at forward angles, particularly in the SHMS
      • Charge normalized yields look comparable for both T2 and T3 (vs T1), but T2 is safer than T3 so we will go with that trigger for remaining Kin-X and Kin-A running
  • Beam Studies underway from 10am to ~9pm (including recovery) with opportunity for 5-pass running mid-day
    • 10am: Hall C entered Controlled Access as planned
    • Target work (2 tasks currently planned; RadCon support needed)
      • Replace a spectrum analyzer mounting plate. Updates: [1]. Re-entered Hall at 3pm (no light in analyzer now) [2]. Issue corrected [3]
      • Take a compass measurement of the field at the carbon foil ladder position if possible. Updates: [4] Initial impression is that these measurements are consistent with Bill/Murchhana's earlier measurements. So target field angle is not the driver for lower than expected polarization.
      • Rotate target to Transverse/270 -- Done https://logbooks.jlab.org/entry/3848250], [5]
    • SOLID cherenkov config change (in parallel) [Done]
    • 4:15pm - 9:15pm: Beam studies, part 2
    • Requires beam to Hall C dump. Position locks at our target should remain ON; MCC will use a 0.5mm raster;
      • Talked to Dan Moser: MCC will start with 10uA tune beam and manipulate injector parameters while logging various beam data. Later will switch to 10--30 uA CW and repeat.
    • 9:15pm: Continue production running in Kin-A, Kin-X at transverse/270 after standard beam profile checks.

Notes for the Future

  • Melanie, Murchhana, Chao, Sylvester: please check good electron yields per Coulomb for Kin-A/X runs with T1 vs. T3 (T2)
    • Mostly complete. Early results don't show any surprises..
    • We will continue with 1 hour (T1) + 3 hours (T2) [and repeat] for remaining Kin-A, Kin-X running
  • Moller measurement planned for Wednesday DAY (tentative)

Pending Issues

  • Check EPR calibrations (particularly for 270deg setting, but others too) [Melanie]
    • Summary log entries: EPR(270, Kin-Z) [6], EPR(90, Kin-X) [7]
  • Bill, Murchhana check compass/field measurements
    • Also checking with Jixie re: modeled fields
    • Need to make a write-up that clearly defines all the different coordinate systems used, swapped power supply/polarity issues, etc.
  • Magnet EPICS PV timeout issue; perhaps reboot skylla10 on Monday?
    • Some Magnets Channels Lost Connection Briefly [8] (Saturday, 2pm)
    • Also had to add more error checking to the angle reporting in the CODA run-start GUI last week too (same softIOC as above)
    • 'Heartbeat' issue reported by Steve Lassiter last week
  • Target polarization for Tommy @ 270 is low (mid to high 30s); Tommy @ 90 seems to have plateaued at 38%
    • Spectrum analyzer collimator was broken at some point and present optics setup may be allowing transient light to interfere with spectrum measurement and QWP scans
    • JP wonders if the field direction is off for the transverse settings (Bill, Murchhana: see note in Target group chat from late Thursday)
  • Beam energy drifts
    • Just something to keep an eye on. Has not been a problem lately.
    • Hall C 5-pass polarization goes down as energy (HALLC:p) goes up [9]

Opportunistic Jobs/Access

Current Run Plan

Monday SWING → Tuesday OWL

  • Beam studies will run from 4:15pm to 9:15pm (or so)
    • Requires beam to Hall C dump. We must monitor beam positions on the stripchart!
    • Position locks at our target should remain ON
    • MCC will use a 0.5mm raster for the entire beam studies program
    • We will start with No Target position
      • Talked to Dan Moser: MCC will start with 10uA tune beam and manipulate injector parameters while logging various beam data. Later will switch to 10--30 uA CW and repeat
    • When MCC switches to CW mode
      • Request target be masked to move target to C-Optics
      • Take 1 hour C-Optics runs with T2 trigger on both SHMS and HMS. Just keep the runs going; don't worry about beam trips or pauses. Adjust prescales to keep the rates around 3.5 kHz in both arms, but no need to 'fine tune', a little extra deadtime is fine for optics running.
      • Add a run-comment that these runs were taken during the Beam Studies program in the Shift Summary and Run database using the add_run_comment command.
  • Continue production data in Kin-A, Kin-X with pol 3He target, Transverse/270 polarization with pNMR/NMR every 5 hrs.
    • NOTE: Take 1 run with T1(3/4) trigger; then 3 runs using T2(EL_real) trigger; Then repeat that cycle.
      • Be sure to monitor and set the prescales correctly.
      • Put T1 or T2 in the CODA comments field for the runs.
      • Note the T1 or T2 trigger type for each run in the Shift Summary and Run database using the add_run_comment command.

Tuesday DAY → Tuesday SWING

  • Continue production data in Kin-A, Kin-X with pol 3He target, Transverse/270 polarization with pNMR/NMR every 5 hrs.
    • NOTE: Take 1 run with T1(3/4) trigger; then 3 runs using T2(EL_real) trigger; Then repeat that cycle.
      • Be sure to monitor and set the prescales correctly.
      • Put T1 or T2 in the CODA comments field for the runs.
      • Note the T1 or T2 trigger type for each run in the Shift Summary and Run database using the add_run_comment command.
-- General plan below this point is fixed, but details may be adjusted as beam/target requires --

Wednesday OWL → Wednesday SWING

  • Moller measurement on Wednesday DAY
    • This will also be used to infer polarization at 1-pass (if it fails, we'll try again on Thursday DAY)
  • Wednesday OWL or DAY during Moller Move spectrometers to Kin-C, Kin-Z and continue Transverse/270 running there
  • Continue production data in Kin-C, Kin-Z with pol 3He target, Transverse/270 polarization with pNMR/NMR every 5 hrs when Moller complete.
    • All runs for these settings use the T1 trigger only

Wednesday OWL → Wednesday SWING

  • Continue production data in Kin-C, Kin-Z with pol 3He target, Transverse/270 polarization with pNMR/NMR every 5 hrs.
    • All runs for these settings use the T1 trigger only

Thursday OWL → Friday OWL

  • Continue production data in Kin-C, Kin-Z with pol 3He target, Transverse/270 polarization with pNMR/NMR every 5 hrs.
    • All runs for these settings use the T1 trigger only
  • 6 am Move to Controlled Access (w/ RadCon support) to begin transition to 1-pass

Friday DAY

  • (Started at 6am) Open target enclosure
    • Install collimators (JP, RadCon)
    • Check on EPR photo-diode status, likely replace it? (JP, RadCon)
  • Ensure fast raster is reconfigured correctly (Expert: Jones, Gunning)
  • Rotate to minimum angles for HMS (11.7) and SHMS (8.5) (S. Lassiter, A. Comer)
  • Configure target for Longitudinal/0 or Longitudinal/180 (TBD)
  • Close up and wait for MCC to establish (1-pass) beam to the Hall

Friday SWING → Monday

  • See task list at Run Plan for 1-pass for more details
    • Initial priority will be PbPt polarization cross check with longitudinal pol. elastics.
    • These have lower priority but will likely be pursued while target spins up
      • 3He, N2 density measurements
      • H2 xsec measurement
      • Pressure curves


Standing Orders

  • Change the IHWP at least every 8 hours when running on glass cells. Call Halls A and B in advance. If there are any issues, call the RC
  • Ensure that all information in the CODA run-start GUIs is correct for every run!
  • If beam goes away for more than 3h, or MCC does operations on the beam that may change the beam tune, then move target to No Target position,
    • verify Harps scans at 3H07A and 3H07B are within spec, and
    • ensure beam is stable (with all locks ON) at 0, 0mm before continuing.
    • Beam recovery procedure has more detailed procedure if needed.
  • New beam positions have been verified and established to be (0,0) mm for all targets.
    • Monitor that beam is at (0,0) using the stripchart on the Wall screen and verify no scraping on the glass cells using the Analysis monitor.
  • Check the position locks are on.
  • Check that CODA is running normally (had one strange hangup lately)
  • Check online replays shortly after starting runs, & full replay results too.
  • 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
    • Follow the updated guidelines in the How-to#Spectrometer_Magnets Spectrometer Magnets How to
    • Spectrometer GUI (go_magnets) should always be visible on Shift Leader computer, hcdesk3
    • 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).
  • When rotating the spectrometer, use HCCAM01 to keep an eye on the SOLID Cherenkov test stand when rotating SHMS (in addition to watching the live angle-cam image, etc). The updated rotation instructions are here: https://hallcweb.jlab.org/wiki/index.php/Spectrometer_Rotation#NOTICES_IN_EFFECT

Useful Links

PolHe3 Polarization Measurements

Misc Links

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