RC meeting and Run Plan, Thursday November 10th

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RC Meeting Information

Time:at 3:30pm today

  • Location: Counting house conference room

Useful Links

Current Status

Accelerator and Hall Status

  • After being down for more than 24 hours we finally got beam around 6pm last night. MCC sent us beam exclusively for an hour in the beginning. Simona started beam checkout.
  • As soon as Hall C was up with 70uA, beam became very trippy. Around 10pm MCC took away beam for 20 mins to correct pathlength. [ https://logbooks.jlab.org/entry/4079522 ]
  • During owl beam was relatively stable. Hall C didn't go above 60uA overnight.
  • Simona finished C-hole alignment during owl. Currently she is doing IC calibration on C-optics. After that she will move to reference cell.
  • The next pass change was scheduled to take place on 11/22 (two weeks from now). Mark has talked to the spokespersons and confirmed that we will stay at 3pass until December 19th. I talked to the PD afterwards and requested her to update the schedule.
  • MCC is thinking about doing beam maintenance either on Tuesday or Wednesday.

Current Issues

Target

  • Frequent laser trips during swing and owl - Solved -- Bill
  • One of the laser fiber temperature is higher than usual. Is it safe to run like that? - Arun, Bill
  • Heater RTD signals are inconsistent. Currently running at lower temperature. What's the status? - Arun
  • Calibration constant at the current kinematic setting. - Hunter will do EPR measurement to get the calibration constant as soon as beam checkout is done.

Subsystems

Polarized Target

  • Current Polarization: 10.2mV -> 12.2mV-> (BB ON + SBS OFF) |
  • If holding field is changed for any reason, do NOT perform an NMR measurement.
  • Hourly screenshots are necessary for the laser gui.
  • Update from target team.

Any additional subsystem updates?

Future Plans

  • Complete beam checkout.
  • Take EPR opportunistically
  • Move to production data as soon as polarization at acceptable level. (See current run plan procedure)
  • Take reference cell data opportunistically.

Other Topics

Experimental progress (for MCC planning meeting)

  • 6.1% of accumulated charge for production data (13.55 Coulombs out of 232)
  • 32% Experimental run time (46 out of 141 days)

Run Plan After Configuration Change

Continue to update 'standard' run plan for 3-pass data taking as necessary.

Current Plan:

  • GEM luminosity studies could be performed between beam restoration and target polarization. See procedure.
  • NMR measurement every 2-3 hours. See procedure.
  • Restore beam. One time process led by Simona before production.
  • Optics and H2 Ref Cell (Sometime during run)
  • Production Run Plan
    • 1.) He-3 runs, at 45uA of beam current. Use ps3==0, ps5=0, all others -1. Take four runs that should each last for one hour. (Check ps5 with Alex)
    • 2.) Move the target to the pickup coil position, and the TO should run an NMR sweep to measure the polarization.
    • 3.) Return to step 1.)

While on shift:

  • Keep an eye out for drifting BPM positions
  • Log all DAQ crashes in the excel worksheet along with the reason for the crash
  • If beam has been down due to accelerator issues perform a checkout of the beam profile by doing harp scans and check beam centering on target using the Carbon hole target, see Simona's procedure: procedure, If in doubt about whether you should go through the beam checkout procedure, call this number: 7578693131.
  • Cross check the rate with what is expected: log
  • Cross check with the expected ion chamber readings: log


Be sure to follow these procedures:

Shifts and Long Term Issues

  • Shift Openings: We're looking good for now! Schedule

Planned Accesses to the Hall

In restricted Access. Survey and alignment ongoing.

Special Requests

Nothing scheduled at present.

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