[Hallc_running] [Revised Logentry] RC Daily Update Oct/29/2023

[billlee at jlab.org]

Logentry Text:
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Since the last update, we have been in the production phase. However, there were a few issues and downtime incidence:

SHMS Helium level reading glitch (https://logbooks.jlab.org/entry/4210957). A glitchy meter causes the SHMS Dipole to overflow. Heidi was manually stabilizing it and determined it would be best to access the hall and replace the meter. Escorted access was set at  20:10 last night. At the same time the NPS crew went into the hall and uncabled the PMT column #3.

5:00 am, NPS Chiller coolant, and crystal zone back temperature sensor below the lo-lo limit. This is a re-occurring issue. If not addressed immediately (within the hour), it would trip off the NPS detector HV interlock. Attempts to reach Aaron Brown were made and failed. Carlos (from France) remotely connected and temporarily set the tripping time limit from 1 hour to 8 hours. Which would give us enough time to address the issue. 13:00 pm, Aadon replied and disabled two temperature sensors (one of them was bad and causing the issue) which might trip the interlock. Short-term-wise, the NPS chiller will no longer be able to trip the HV interlock from the NPS temperature or coolant sensors. 

Since run #2383, 12:55, we introduced a new trigger threshold based on Alex's suggestion (reducing the two-photon threshold from 750 to 650).

Additionally, to further improve the smoothness of the data production, the spokespersons jointly made decisions to take action to eliminate the above issues in future runnings:
*    If possible, turn off (warm-up) SHMS dipole during an accelerator maintenance day.
*    Disabling the interlock tripping features in the NPS temperature and coolant.
*    Shift crews no longer are required to fill in all details on the run sheet. For a new configuration, start a new page and carefully fill in all of the details; if the configuration stays the same, only kinematics setting, date, and initial are required;

For the new setting, we collected 460.9 mC of integrated charge and started to lose modules on the 4th color. See attached pictures.

Current Status
    Production with the newly reduced two-photon threshold. If possible run LD2 production runs (1 hour long) at 35uA. 


Near Future Plan
We will postpone the Monday corrector coil beam steering test, to the next setting change, since the current setting doesn't require the corrector coil.

Wednesday, November 2, 7:30 a.m.: sweep the hall open for maintenance first thing in the morning. We will attempt the following maintenance items:
1. NPS students will remove all PMTs + bases from the column. Hall tech support is needed for this part.
2. NPS shielding installation if ready
3. Heidi is looking into the possibility of warming up the SHMS dipole. If feasible, SHMS dipole will be warmed up.
4. Chandan and Dave Mac checking/maintaining will access and check the HMS hodoscope patch panel. to address this issue: https://logbooks.jlab.org/entry/4210267
5. Aaron will push a new code for the NPS chiller controller.
6. DAQ repairs. Scalar server related.
        
    Tuesday, October 31, 11:00 a.m.: We will invite Vald to give an insight into the high radiation test results. 

I am sure the maintenance list will grow as we get closer to Wednesday.

We will have an RC meeting tomorrow.

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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/4211924
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