[Hallc_running] [New Logentry] Saturday RC update for Hall C

mack at jlab.org mack at jlab.org
Sat Jun 22 13:10:02 EDT 2019

Logentry Text:
 It was a rough nite, but a lot of basic checkout got done. Thanks to the shift crews, Simona-as-expert, people who stayed late, person who got called on the NMR, etc. We're now limping along, trying to figure out what part of the run plan we can do with no ESR which may be down until Monday. (No way to do lumi scans nor LH2-based systematics or physics. Ouch!)

Got beam on Friday swing shift and started on Gaskell's run plan CliffsNotes in hclog 3689431 : The FR was checked and the hole centering got done. ESR crashed hard for no apparent reason, so we lost active cooling of the target, limiting us to 5 muA on solid targets. Greg stayed late to manage the warmup. Owl crew completed the trigger level pi/e rejection study at the unusually low HMS momentum of ~0.45 GeV/c . (See Simona's extensive plots.) Despite an initially balky HMS NMR which eventually required a power cycle, a sieve measurement was done, and clearly multiple scattering is still proportional to 1/P. Near the beginning of day shift, additional sieve measurements were taken at 0.8 and 1 GeV/c to bracket the lowest momentum settings for the upcoming VCS run. (See Mark's extensive plots.) Harp scans were redone. I probably forgot something. Ah yes: there's no functional women's bathroom in this building, and I don't have an office in CC due to the water being shut off.!
  I hope this isn't another Infrastructure Week. 

At the moment the day crew is trying to do a beam energy measurement. 

Later, with the target from the beam but with the beam rastered, we'll 

1. try to establish higher beam currents, then 

2. probably do the longest bcm calibration in the history of JLab 

There will be no RC meeting today. Send me ideas for how to usefully employ this billion dollar accelerator with no high power target. 



This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3691745
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