[Rgc] [Revised Logentry] Daily RC Summary

[kuhn at jlab.org]

Logentry Text:
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Summary March 3-4

A repeat of the past 2 days: nearly no data for Day and little for Swing shift. Better overnight. At least we have an agreement that no more attempts to deliver beam to Hall A will occur until Monday, so once/if beam is back, we should get some better ABUs.

Day Shift 3/3: Beam turned off around 9 - another attempt to fix the problem with Hall A. We make use of the downtime to anneal the target. Anneal works well - polarization climbs back up to over 40%. Some minor fixes for RICH and CND (new pedestals).

Swing Shift 3/3: Waiting for beam. Finally coming back around 8 p.m. (not very stable). Major issue on our side: DC HV trip, Sec6 R1 SL1 G01 32. Decide to keep running - one SL section 8 wires wide is off. Probably a broken wire - Morgan will isolate the affected HV cable and remove it during day shift Saturday to reduce the affected area to just 8 wires. About 1 hour of good data.

Owl Shift 3/4: Mostly taking data (6 hours) on ND3, positive polarization around 42%. Several issues with DAQ; one of them is that the FT trigger alarms repeatedly. Raffaella suspects temperature increase (chiller needs more ventilation) and radiation damage. Planned action: change the alarm threshold and put a fan on chiller.

RC meeting Saturday morning: Conclusion about Hall A: Something is wrong with the 4-pass separator, which is required for Halls B-D but doesn't work for Hall A. Fixing it is a major interruption of running for all Halls - now tentatively scheduled for Tuesday the coming week. Meanwhile, Halls B-D should receive beam (when available - right now it's off again), except maybe some additional diagnostics to be done Monday morning (target change for us?)

Since there is nothing for us to decide right now (that I know), we won't have an RC meeting today. Send email if you have something you would like to discuss.

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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/4143161
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