RC Update and Run plan for Sep 5,2020

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RC Meeting Information

RC Daily Meetings are at 4:15 PM, remote

• Bluejeans remote connection information:

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Accelerator Status

• Sep 04 Swing (yesterday):
  • 1L19 component down time (~ 14:04 - 19:07) [1]
  • Beam restored to Hall C at ~20:30 [2]
• Sep 05 Owl/Day (today):
  • At 23:14, 2KN Cold Box Trip took down Injector / North Linac RF cavities. Estimated recovery time ~4-16 hours [3]
  • As of 8:45, accelerator recovers from "Cold Box Trip" and MCC attempts to send tune beam to all Halls
  • Summary of Beam Current during Day: [4]

General Updates

• Sep 04 Swing (yesterday):
  • At 20:30 the initial attempts to steer beam into the Hall were made after a ~ 5 hr revovery from 1L19 [5]
  • From 20:39 - 20:52, Harp scans were done to check beam profile [6], [7]
  • At 21:00, CW beam restored to Hall C, and at 21:18, Pol He3 scraping checks were concluded [8]
  • At 21:19, d2n Pol He3 production data-taking resumed for ~ 1 hr of beam-on-target. We still needed ~2.5 hours at IHWP = IN to balance out the ~4 hrs at IHWP = OUT taken on Sep 04 (Owl, Day)

• Sep 05 Owl/Day (today):
  • At ~23:14, the accelerator 2KN Cold Box Trip took down the Injector / North Linac for ~ 4 - 16 hours [9]. While the accelerator recovered:
    • EPR calibration was done after target was spun-up to +270 deg [10], [11]
    • Target was rotated back to +90 deg and NMR measurements were taken every ~5 hrs to bring polarization back to ~40 % faster [12]
  • As of Sep 05 Day (08:16), the most recent NMR measurement indicated a target polarization of ~39.7 % [13], and we decided to resume d2n production before the "Cold Box Trip" incident

Run Plan

• Contnue to collect d2n Pol He3 data for the next few days (until notified by d2n spokespeople that sufficient data has been collected)
  • Currently, have concluded ~2.5 hrs of data at IHWP = IN configuration (completed before end of day shift), and then we changed to IHWP = OUT and continue data-taking for ~8 hrs of beam-on-target.

Recent NMR Polarization Measurements (after "2KN Cold Box Trip")

• Sep 05 (Owl):
  • NMR @ 02:06 -> 33.4 % [14]

• Sep 05 (Day):
  • NMR @ 07:14 -> 39.7 % [15]
  • NMR @ 12:42 -> 42.2 % [16]

Recent IHWP Changes

• Sep 03 (Swing, as of 19:58) | IHWP = IN
• Sep 04 (Owl, as of 04:00) | IHWP = OUT [17]
• Sep 04 (Day, as of 12:01) | IHWP = IN [18]
• Sep 05 (Day, as of 14:55) | IHWP = OUT [19]

General Reminders for Running

• New beam positions have been verified and established to be (0,0) mm for all glass cells. Only need to check beam is at (0,0) and verify no scraping on the glass cells.

• Make sure the raster size is correct (4--4.5mm)

• Monitor beam parameters/configuration very often and post an entry like this at the beginning of your shift and when run conditions have changed

• Running on cell targets: raster always ON (4--4.5mm, size will be determined by the scraping checks), orbit locks ON, current ramp rate 1 muA/sec

• Always take 120Hz of EDTM

• Fill the BTA with realistic numbers. If the desired beam current is not delivered prorate your ABUs!

• Change the IHWP at least every 8 hours when running on glass cells. Call Hall A in advance to request. If there are any issues, call the RC

• Note that the autoload of IHWP status in the Start-Run GUI doesn't work anymore so please double check IHWP setting before you accept the GUI value.

Notices in Effect for Shift Crew

• Follow all COVID rules and regulations as well as remind each other. Additional food guild lines:
  • All food are removed from the round table. Fruit are now store in the fridge, and individually packaged snacks are store on the shelf below the coffee machine.
  • No food near the SL and TO control station. If you would like to eat something, please use the empty round table (used to store food in the past), that is now empty and sanitized.
  • New coffee guide line: it is much preferred if you can bring you mug for the coffee. During the shift if one need to drink coffee near the control station, then the coffee mug must have a lid or have some kind of cover.
• Beam positions: [20]
• Policy for CANS-related hall status change: Make a logbook entry when the hall goes in, or comes out of laser-controlled access.
  • Good examples for entering and leaving laser access.
• Inform the RC of any access that the Target Team requires. The RC will coordinate with RadCon to make everything run smoothly.
• 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[21]
• An new reference Cell refill procedure: New procedure
• Magnet policies
  • Spectrometer GUI (go_magnets) should always be visible on Shift Leader computer, hcdesk3
  • Slow ramping procedure of the SHMS, go small steps to the MOL, an great example (1 hour 30 min process)
  • 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.
  • New updates to the magnet momentum ramping procedure: https://hallcweb.jlab.org/wiki/index.php/How_to_operate_and_monitor_the_Spectrometer_Magnets
  • If any of the Spectrometers magnets trip, take a screenshot of the PSU window and check the hall for smoke or water with the camera before resetting the interlock and post it to hclog
• 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 instruction can be found: https://hallcweb.jlab.org/wiki/index.php/Spectrometer_Rotation#NOTICES_IN_EFFECT
• New SHMS matrix element

Planned Accelerator Configuration Changes

• Hall C to 1 pass on September 17/18, Thursday/Friday