[Halla_running] [Revised Logentry] RC daily update Oct 22 2023

[jcaylor at jlab.org]

Logentry Text:
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RC daily update 10/21

URGENT! We need a SL for TODAY (10/22) during swing shift. The trade request is for incomplete training and they will not be allowed on site.
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General Updates:

The last 24 hours have been pretty smooth running. I’ll lead with the headline of ~3.3 C of corrected charge collected in the since 7 am yesterday morning until now! After the polarization took a little dip because of a bad fit it has since recovered to ~47 % in beam. 

Throughout the day the bleedthrough that we saw during owl on 10/21 was confirmed by MCC but since Hall C returned to < 20 uA we didn’t see much of an issue. Hall C went back to 30 uA around 2:30 am and the Crew Chief and I sat down together and tracked some of the relevant ICs and GEM currents, no issues were seen with bleedthrough last night (https://logbooks.jlab.org/entry/4205139). 

The GEMs still seem a little more sensitive than we would like when the beam is coming back from a trip. We saw a couple GEM HV trips from beam excursions of ~0.2-0.3 mm during beam ramp up. In addition, the GEM experts determined that the reason we cannot get the SBS GEMs in the DAQ is because there is a low voltage issue that needs half a day to fix. This will be done during the maintenance day on Wednesday (10/25). 

The HCal had 1 issue during the night around 3:15 am. It seems the HV tripped on a few channels but the VSet somehow also got set to 0 V at the same time so there was not really an alarm handler warning. The Shift crew noticed some missing channels in the replays and contacted myself and Jiwan (https://logbooks.jlab.org/entry/4205169). The HVs were turned back on and we have had no further issues. Jiwan will look at this in more detail today.   

Run plan is to continue taking production data until the sieve is put in Monday morning. The plan is to put the sieve in starting around 8:15 am Monday morning. Note that OPS is given priority during this time from 9 am to 1 pm and requests from the hall are not taken. That means we will be required to take 45 uA on carbon optics the whole time during beam studies
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We will plan to have no 3:30 meeting Saturday and Sunday unless there is need.


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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/4205402
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