[Rgc] [New Logentry] RC summary for September 27

[hovanes at jlab.org]

Logentry Text:
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Unfortunately, another day with low ABUs. The day shift started with no beam, and the beam came back at around 8pm. We performed the beam restoration procedure with wire scans at 2C21 and 2C24, and then proceeded to Moeller runs. We did two runs in identical conditions (https://logbooks.jlab.org/entry/4047006 and https://logbooks.jlab.org/entry/4047014) with about 82% beam polarization (81.3 +/- 1.5  and 83.8 +/- 2.6). We did not complete the second run as the beam disappeared again and the rest of the swing shift went without beam.  We got the beam back at 3am during the owl shift and the beam was restored to FCUP. We had three probably independent problems when trying to turn detectors and DAQ on: 

o MVT HV  Sector 1 L5 DRIFT would not hold HV. Lowered the setpoint to 1200V and gradually raised it up to the nominal 1300V. 
o RICH tiles disconnected. RICH recovery solved the problem quickly.
o Trigger bits 2 and 9 missing in mon12 plots and  something like "...Bit1-6" persistent alarm on the alarm tree and trigger GUI. We did not succeed fixing it by restarting DAQ and had to call Sergey. He fixed the problem, but I do not know what caused it.  

After fixing these three problems we took one run on NH3 positive polarization and HWP OUT, and then switch HWP to IN and continued taking data on positive NH3. The target polarization was around 74%. PROD66_PIN configuration runs are 17084 (HWP OUT) and 17085 (HWP IN). 

Day shift summary : https://logbooks.jlab.org/entry/4046694
Swing shift summary : https://logbooks.jlab.org/entry/4046923
Owl shift summary : https://logbooks.jlab.org/entry/4047063 

We roughly took 60M events before the day shift. 

Plans: 

Take data on  NH3 positive polarization with HWP IN until tomorrow morning. 
Switch target polarization tomorrow morning ?
Take data HWP IN and HWP OUT on Wednesday before maintenance on Thursday day shift ?
Solenoid polarity plans? 

Today's RC meeting is at 2pm. 

Hovanes. 


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