RC meeting and Run Plan, Monday Sept. 11, 2023

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RC Meeting Information

Time:at 3:30pm today

  • Location: Counting house conference room
  • ZoomGov Meeting Connection Information


Useful Links

Readiness for Beam

Accelerator readiness:

  • CG: beam restoration to hall A projected to start swing Tue Sept 12. I have "un-cancelled" the Wed OWL shift since there is a higher than not probability that the accelerator will be able to deliver CW beam. Bill Henry will be on-call to provide support for the CW portion of the checks (target protection checks, ion chamber checks).
  • SSG only has the Moller Target to check; Ellen will work through at least the FSD portion today or tomorrow morning
  • ZR: plan to do checklist on Tue (everyone out of the hall by lunch)
  • ZR: facilities found that the power cord from the rack to the feeder panel melted; logbook entry incoming; shorted the power cord by ~12feet.

Shift schedule

  • CG: OWL on Wed only has a SL; we need a TO

Subsystems Checklist

For each subsystem we ask that the responsible person go over the following points:

  1. The overall status of your subsystem
  2. Will your subsystem be ready well before Hall lock-up on Friday or at the latest by Monday morning?
  3. Does your system being ready depend on your team only or are outside resources required?


  • SBS magnet and Bigbite magnets ramp and hold
    • works; acid flush rescheduled for the long down
  • Corrector magnets:
    • complete
  • Target status (magnets, measurements, laser, installation, alignment, polarization, power etc)
    • Installed on Friday to get it polarized; only got to 20% => laser misaligned (fixed today and polarize tonight)
    • Target install: Kate, Arun, Bill currently installing the carbon foils and probably will have to push alignment and laser checks in the morning
  • HCal (Jiwan Poudel)
    • ready
    • doing final checks
  • Bigbite (Arun Tadepalli)
    • Gary: replaying cosmics run now and will update if something needs fixing;
  • Counting House Alarms (Bill Henry)
    • Bill tested the alarms and instructions for shift crew response in the wiki (needs further revision?)
  • DAQ (Alex Camsonne)
    • one channel of GRINCH has an issue (HV tripping -> Eric/Todd). Power supply works. Group of PMTs make the HV trip. Todd is working on it now.
    • SBS GEMs are hanging the DAQ (Vimukthi)
    • will take another cosmic run tonight
  • GEMs (Holly Szumila-Vance)
    • Vimukthi: fixed issue with SBS and BB GEMs (LEMO cables was the culprit - logbook still needs to be made) => check on this
    • ChG: Ellen has a mass flow controller and needs to find some time to install it (not a show stopper - gas mixture changes from 79%Ar to 70%) => Chandan can also change the MFC; this is outside of the hall can be done later
  • Moller polarimeter (Don Jones)
    • Target motion not working (Ellen looking into it)
    • we want to do at least one measurement at the beginning; all systems that could be checked now (besides the target) work as expected
    • magnet should finish cooling by this evening
  • Hodoscopes:
    • waiting on replay

Preliminary run plan

  1. First, bring the beam safely into the hall (Beam recovery procedure - Jiwan and William Henry https://sbs.jlab.org/wiki/index.php/HOW_TOs#Beam_Recovery_Procedure)

Q: At what stage is the SBS turned ON? WH: will post links to the corrector checkout

  1. BigBite/single foil location reconstruction (~20 mins?) - BigBite + HCAL detector experts on call consulting analysis experts like Andrew/Sean (magnet on)
  2. Target performance assessment by target group - Arun (Why hasn’t the target reached xx% polarization?), tell us when we will get there (Target group - Arun) and plan for those hours in between
  3. Take production data!

List of items in case target isn’t ready:

  1. Take data on reference cell at 10 atm H2 (portions that add up to 1 day)
  2. BigBite Sieve slit
    1. with 8 carbon foils and take optics for 1 hr at 40 uA (Sean/Andrew - confirm time)
    2. 1 hour for single foil (magnets off) => Chance BBcal HV setting to appropriate values
  3. Moller measurement depending on availability of people and results from Hall C


In person: Ciprian G, Alexandre C, Chandan G, Hanjie L, Zak R, Don J, Bill H, Eric F, Jiwan P

Online: Skorodumina, Bogdan W, Jimmy C, Ole H, Gary P, Sanghwa P, Andrew P,