RC Update and Run Plan for March 20, 2020

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Current RC: Jay Benesch benesch@jlab.org

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

General updates:

  • Hall is in restricted access.
  • Let the RC, Jay Benesch, and Walter Kellner know about any non-pivot work you'd like to take place during the March 13-20 down in Hall C. (Please CC Brad as well.)
  • Field measurements complete. First part of survey complete.
  • B and C laser seeds were switched Thursday morning. https://logbooks.jlab.org/entry/3806164
  • The work items are currently:
    1. A 3He compressor checkout for the x > 1 experiment next year (Meekins/RadCon);
      RC mentioned this at 0800 meeting 3/18.  Dave Hamlette said he'd coordinate with Meekins.

Current Run Plan:

  • continue Solid prototype installation

Friday-Saturday

  • Both beamline windows were mounted Friday, pump down Friday with good leak check. Waiting on ion pumps tomorrow.
  • ESH evaluation of target ladder and laser platform work 0830 Friday. Work rules and PPE defined. Work underway.
  • Install reference cell (done Thursday evening), overnight leak check fine Friday morning
  • Steve Lassiter checked rotation capability Friday.
  • One of the 3H07B harp wires is visually damaged per I&C. This wire has been providing readings that I didn't believe. It is redundant with the third wire. I&C found it broken in an innocuous place so no action was taken.
  • Install target cell and pump laser alignment through 2200 tonight.
  • Recommission target and start spinning He3 up overnight Saturday (through SWING and OWL as needed)

Notes for the Future

  • At d2n startup, it would be a good idea to quantitatively check the dispersion at the target. I (D.Mack) don't think we need a tight spec, but if it's as sloppy as 1 cm/% (hence a decent spectrometer), then we're more at risk for things like how much the beam moves when the locks are off, or scraping from an off-energy tail on the beam. Jay:MQA3C13 can be adjusted to change horizontal dispersion.


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

Pending Issues

  • Be sure to restart main alarm handlers and turn up speaker volume before operating magnets! [1]
    Be sure to restart target alarm handler and turn up speaker volume before operating target! [2]
    pNMR issues
    software
    Software/driver issue needs to be resolved. Checkout during next non-production down time (Moller or SHMS fix)
    EPR problems
    [3] saw some progress on Tuesday [4], 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
    PS commissioning/installation (Todd, Bill) (Bill got a filter design from the vendor and has ordered parts.)
    New filter (for 180 Hz) to install for current mode operation fix. Can always go to voltage mode if it doesn't work.
    NMR Calibration Constants
    Verify that calibration constants and input values associated with NMR and other polarimetry are consistent and will be correct when the software is restarted
    [5] [6] [7] [8] [9] (Bill, Junhao, Arun)
    Beam trips
    Persistent BLM and 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)
    USB bridge
    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
    • Ensure issues on Sat, March 14 have been corrected [10]
    IOC issues
    Green now: Rebooted 3/2/20 with Dave Gaskell assistance. OPs wished to reboot hung iochc10 [11], noted in December as well [12]
    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.



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