RC meeting and Run Plan, Friday Oct. 12

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Status

  • Beam quality
    • Bottom line: things were mostly fine during swing until 11pm
    • Current fluctuating at 40uA until we moved SHMS, then we requested 35uA\
    • BLM trip investigation for the last 5+ hours
  • Progress
    • Finished kinematic point (theta_Shms=9.42) after 48+ hours with 46%, short of 50-60% goal
    • Moved to new kinematic point (theta_Shms=6.495), need to limit current to 35uA

Issues: Resolved

Issues: Requiring attention

New

  • SHMS at small angle (part 1)
    • SHMS raw singles rates very high
      • Found to be around 700kHz at 35uA --> 80% tracking efficiency
      • Briefly ran at 30uA to see increase in efficiency when running at 15% less current --> 83% tracking efficiency
      • Decided to run at 35uA
  • SHMS DC1 tripping during beam studies
    • SHMS DC1 tripped when beam studies reached 50uA
    • Decided to leave HV off until we are back to production running
    • Instructed swing shift leader to switch back on if they (finally) finish their beam studies
    • This limits what we can do during the luminosity scan

Ongoing

  • SHMS at small angle (part 2)
    • Added during RC meeting and Run Plan, Thursday Oct. 11
    • (Might) need new limits on diffusor ion chamber if we run above >=50uA (Jay Benesh confirmed might be the case), more info here.
      • Not an issue right now because we are rate-limited to 35uA,
      • Might become issue at the next momentum setting and the luminosity scan
  • HMS Dipole LN2 fill level very high (essentially full)
    • Added during RC meeting and Run Plan, Thursday Oct. 11
    • Not urgent, To be resolved if we can fit in access (maybe next week
    • Not urgent, small ice ball forming in non-critical location (we're watching it)
    • Cause: seems like JT-4 is stuck again
    • Will coordinate with Andy Kenyon early next week for opportunistic escorted access
    • Alarm disabled for now, re-enable when fixed. Instructions

Request (non-urgent)

  • RadCon wants to put a small detector in the SHMS hut during the next opportunity
    • Needs few hours, communicate with Brad when next opportunity arrises
  • Hall D needs opportunistic 1shift of HallC down for beam studies, not pressing right now (needs to be done before end-of-run)
    • Unlikely this will happen in the next week