RC Meeting, Thursday, September 10, 2021

RC Meeting Information

RC Daily Meeting at 16:30, (remote)

• Bluejeans remote connection information:

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 To join via Room System:
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 Meeting ID : 861439920
 To join via phone :
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Useful Links

• Autumn 2021 Shift Schedule
• Hall-C Controls
• Hall-C Logbook
• MCC White Board

Current Status

• Taking the beam we can get!

Current Run Plan

• Finished the the LH2 and dummy target runs for the first part of the first setting
• Tweaks to the analysis have cleaned things up a bit, we can cut on the coin time and get a nice MM spectrum, various detector calibrations need fixing
  • The hodoscope particularly needs work
  • See here for some nice plots!
• Running LD2, unfortunately, need to redo an hour or so of data (see Hall status)
• If things go well, we will need to rotate either late Owl or early Day tomorrow
  • An extremely optimistic scenario is late Swing, early Owl today

Planned Accesses to the Hall

• Joe B and Larry both requested an access when possible
  • See Hall Status, will drop to controlled during Hall D setup
  • Scheduled to start Monday 06:00 - Let me know if you can do your work with an escorted access or not

Accelerator Status

• Very smooth through most of swing yesterday, issue with the north linac took us down from ~ 22:00 to 00:30
• Beam a little trippy overnight, OK so far today

Hall Status

• CODA a little unstable - rates too high
  • For Physics settings, reduce the beam current, do not change the coin prescale (PS5) from 0
• COIN rates on the LD2 are extremely high, this is what prompted the Owl shift workers to try adjusting the prescales (they were seeing enormous deadtimes and rates - ~ 7kHz un-prescaled coin rate at 70 uA)
• This will only get worse at smaller angles
• Beam trips causing an alarm when running with LD2 - related to the fan?

Notices in Effect for Shift Crew

• Please read safety documentation (https://hallcweb.jlab.org/safety-docs/Fall2021/) and sign in the "yellow binder" in the Counting House (when it is there)

Plans going forward

• BCM calibrations, do over the weekend?
• Arc energy measurement, over the weekend if possible
• Bullseye scan