Revision as of 13:57, 27 August 2020

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RC Meeting Information

RC Daily Meetings are at 4:15 PM, remote

General updates

• Started the swing shift with beam tuning/harp scans. Followed by production running with PolHe3 longitudinal running. (HMS is at 20 degrees -4 GeV and SHMS is at 18 degrees -5.6 GeV (Kin C-Z))
• Nominal beam positions on glass cells are updated https://logbooks.jlab.org/entry/3835151
• Compton Ion Chamber trips https://logbooks.jlab.org/entry/3835163
• HMS Q2 trip due to LHe levels (~30%) https://logbooks.jlab.org/entry/3835122
• Concluded the production running with PolHe3 longitudinal at 12:30am and took an escorted access:
  • Evacuated the reference cell which was filled with N2 and filled the reference cell with He3 (135 psig) (https://logbooks.jlab.org/entry/3835347)
  • Air flow check in laser box?
• AFP loss and temperature tests done by Mingyu before rotating PolHe3 to transverse (https://logbooks.jlab.org/entry/3835396).
• Rotated target spin to transverse 270 deg (https://logbooks.jlab.org/entry/3835381)
• EPR/NMR calibration by Junhao/Mingyu (https://logbooks.jlab.org/entry/3835512) (https://logbooks.jlab.org/entry/3835543) (https://logbooks.jlab.org/entry/3835587) (https://logbooks.jlab.org/entry/3835598) (https://logbooks.jlab.org/entry/3835607)
• Escorted Access today:
  • Troubleshooting the transport ion chamber issue (https://logbooks.jlab.org/entry/3835254), Jerry Kowal's team is taking care of this.
  • Reset rotation drive controllers (Joe Beaufait) (done)
  • Connecting the spare air compressor that Walter rented. (https://logbooks.jlab.org/entry/3833255) (Larry et al) (done)
  • Tweaking the EPR RF amplifier gain setting to troubleshoot the noisy NMR (https://logbooks.jlab.org/entry/3835639) (done)
  • Check air flow/fan in laser box (https://logbooks.jlab.org/entry/3835710)(Brad)
• Last NMR:

Pending problem(s) / Things to track

• Diagnose/resolve the transport ion chamber issue. (Investigation is ongoing by Jerry Kowal)
• Monitoring
  • phi distribution dip
  • New sets of monitoring plots for the current setting?
• Spare reference cell options/status [Todd, JP]
• Target mounting for Tommy (next cell) [Arun, et al]
• Target mounting for Butterball [Arun, et al]
• 1-pass changeover planning

Current Run Plan

• Finish data taking with reference cell (He3) and start taking production data with PolHe3 transverse (HMS is at 20 degrees -4 GeV and SHMS is at 18 degrees -5.6 GeV (Kin C-Z))

List of Tasks for the Next Down Time

• Simona SoLID cherenkov work

When there is an opportunistic access

• Fill reference cell with Helium
• Check air flow in laser optics box
• Work on air compressor: if the access is during the day shift, we can check with the techs to see if they can work on the air compressor that Walter rented. It needs to be connected.
• Reset the SHMS rotation control driver
• Diagnose/resolve the transport ion chamber issue. (Investigation is ongoing by Jerry Kowal)

Recent polarization measurements

@ 180 deg

• Swing (08/25) 16:42 NMR - 39.5%
• Swing (08/25) 23:50 NMR - 45.2%
• Owl (08/26) 5:02 NMR - 45%
• Day (08/26) 10:05 NMR - 45.8%, pNMR - 45.3%
• Day (08/26) 15:33 NMR - 44.1%, pNMR - 46.2%
• Two more pNMR measurements required

Current Run Plan

Normal Production running

• Prerequisites

• New position for Briana and Will
• 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

• Run plan

Production Run Plan on longitudinal (180 position) applies to Aug 26 day shift

• 1 hour run
• Flip IHWP every ~8 hours (beam)
  • Submit changing request to Hall A and ensure they comply with the request within the hour. If difficulty, call RC immediately.
• NMR + pNMR measurement every 5 hours (beam or no beam)
  • Measure pNMR 20s before NMR. pNMR instruction: https://hallcweb.jlab.org/wiki/images/5/56/PNMR_Training_Slides_20_08_25.pdf

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: [1]
• 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[2]
• 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 1st pass on 8/31 and back to 5th pass on 9/03

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