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

• Started running during yesterday swing for kinematic Group 15 (Q2 = 4.77, x = 0.6, pi+)
• Since swing yesterday beam was less reliable than weekend, e.g. two separate downtimes >1hr in owl shift.
• At ~13:40 today completed kinematic group 15
• Reconfigured 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.
• Currently running group 11.
• For 11-3 rate test setting will be performed (changing beam current and cross-checking good coincidence yields)
• RC Daily Update Wednesday, November 21

Current Run Plan

• Order of Kinematic Groups
  • Group 11 (Q2 = 5.0, x = 0.5, pi+)
  • 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: aerogel change and HGC work needs to be coordinated with Walter K., we must be in restricted access for this work

Planned Accelerator Configuration Changes

• Sunday, Nov 25(?): Hall A goes offline and MCC wants to conduct high current beam study of energy spread at 40 uA. It is unclear that we will be effected
• Monday, Nov 26: Energy change to 1.86 GeV/pass, we will be moved over to 500 MHz laser.

Special Requests

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