RC meeting and Run Plan, Wednesday Nov 21

RC Meeting Information

RC Daily Meetings are at 4:30 PM, 2nd floor Counting House Meeting Room

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Useful Links

• Detailed Kinematic Group Settings
• KaonLT-SIDIS Group 2018-2019 Shift Schedule
• Hall-C Controls
• Hall-C Logbook
• MCC White Board

Current Status

• Since swing yesterday beam was less reliable than weekend, e.g. two separate downtimes >1hr in owl shift (details in RC daily update).
• At ~13:40 today completed kinematic Group 15 (Q2 = 4.77, x = 0.6, pi+)
• Reconfigured and currently running for Group 11 (Q2 = 5, x = 0.5, pi+)
• During HMS spectrometer move, drive controllers flagged red, reset not possible, tech-on-call called and controlled access made by J. Beaufait to reset shunt trip breakers on HMS and SHMS.
• RC Daily Update Wednesday, November 21

Current Run Plan

• Order of Kinematic Groups
  • Group 11 (Q2 = 5.0, x = 0.5, pi+)
    • For 11-3 rate test setting will be performed (changing beam current and cross-checking good coincidence yields)
  • Group 12 (Q2 = 5.0, x = 0.5, pi-)
  • Group 8 (Q2 = 3.979, x = 0.5, pi-)
  • Group 7 (Q2 = 3.979, x = 0.5, pi+)

Notices in Effect for Shift Crew

• If the HV trips for SHMS S1Y5B contact Simona M. DO NOT change the HV from the nominal value!
• Shift leaders, please fill out the check list once per shift!
• It is no longer required to fill out the standard.kinematics file online, it is now done automagically
• Split the large desired charge between multiple runs (~1 hour per run)
• Listed currents are estimates. For runs at less than 60uA, increase current until SHMS singles rates are between 400k-500k.
• How-to power cycle PLC I/O chassis: https://logbooks.jlab.org/entry/3625862, https://logbooks.jlab.org/entry/3625900

Current Issues

• Worsening of coincidence time resolution
  • Cause of coin. time jitter (resolution loss) may have been found? -Brad S.
  • Coincidence time after insertion of passive delay -Dave G.
  • Follow-up Re: Coincidence time after insertion of passive delay -Dave G. with comment from Dave M.
  • More jitter tests -- nothing found on scope... -Brad S.
  • HMS/SHMS TOF resolutions using hodoscope beta -Mark J.
  • RF time and coincidence time -Mark J.
  • Yet more jitter tests -- found small issue w/ ref time, but nothing that impacts coin. times -Brad S.

Planned Accesses to the Hall

• Monday Nov 26 energy change and move to restricted access. Current plan according to MCC white board is to lock up Hall Tue swing.
• Monday Nov 26:
  • Aerogel change
    • Vladimir Berdnikov and Walter Kellner's team
    • Need SHMS below 20 deg. and the HMS above 40 deg.
    • HallC ramp
    • SHMS HB magnet field OFF, detectors HV OFF, roof OFF (craning operation)
    • SHMS hut, detector site will be occupied (craning operations)
    • 8h for operation minimum
    • As less activity in the hall as possible
  • HGC work, Walter K. is aware, Brad and others from University of Regina will work around aerogel change.
  • Walkthrough request in morning for University of Regina.
  • Dave Meekins has requested access to Hall and to the top of the target with manlift to diagnose the issue and possibly affect a repair on the loop 3 JT valve. Need to coordinate with Walter.
• Tuesday Nov 27:
  • Walter Kellner and Steve Lassiter will install brushes (originally planned for Tuesday and Wednesday, need to coordinate if possible only to be done on Tue)

Planned Accelerator Configuration Changes

• Monday, Nov 26: Energy change to 1.86 GeV/pass, we will be moved over to 500 MHz laser.
  • Current plan is swing Tue 11/27 Hall will be locked up (see MCC scheduling board).
  • Target group recommend keeping target cold for 4 shifts between Monday Day and Tuesday Swing (Tue D. Meekins removing tritium from Hall A so unavailable to re-condense in C).
  • Sunday D. Meekins will warm up the Hall A target (shouldn't be affected)

Special Requests

• Harp scan at 3H07A and 3H07B with raster off to address possible issues with harp (https://logbooks.jlab.org/entry/3624463)