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QuickPic - Box Supply/Shunt Screens
CREW CHIEF SIGN IN
THOMAS JEFFERSON NATIONAL ACCELERATOR FACILITY
ACCELERATOR OPERATIONS CREW CHIEF SIGN IN FORM
Date : 02-22-26
Time : 07:12:45
Day : Sunday
Shift : Day
Crew Chief : Humphry
Program Deputy: Buttles
Team : X
Arm : RadCon
Designated SSO: Thomas
LERF Operator:
Operators : Thomas
This stamp certifies that the above Crew Chief has read/reviewed/received the following:
QuickPic - End of Shift Magnet Screens
The OPS DRVHs for the following cavities have been updated: 2L13-2
2L17 Reduced to Target GSETs
2L19 Reduced to Target GSETs
Pushed 2L14 a bit harder tonight
The OPS DRVHs for the following cavities have been updated: 2L14-3
The OPS DRVHs for the following cavities have been updated:
2L14-3
Username: deir
Date/Time: 02-22-26_05:23:03
RF Status: Good
Tuner Status: Good
Comment: DRVH=8.500 High GASK w/ 0 RATN. Cavity starts to SOS at higher gradients with even without beam.
Previous OPS DRVH: 0
Special Instructions:
The following cavity histories have been updated: 2L16-6
The following cavity histories have been updated:
2L16-6
Username: deir
Date/Time: 02-22-26_05:14:00
RF Status: Bad
Tuner Status: Good
Comment: Cavity TDETA is stable at gradients >6.5 MV/m, but RFCM should probably be checked out. Could be run at lower gradients with tuner in manual. Leaving it GSET0 for now: https://logbooks.jlab.org/entry/4472425
Special Instructions:
Maintenance Tag: Component: Operator Entry - See SME
2L20 Reduced to Target GSETs
2L21 Reduced to Target GSETS
Recovered 2L16-6...RFCM troubles?
Did an OLT and recovered it at 3.5 MV/m. CFQEA and GMES were unstable during the OLT process, CFQEA moreso. It was oscillating by as much as +/-20 deg. I chose a spot where GMES was the most stable and recovered it there while keeping the tuner in manual.
Forward power readback seemed to be responding and was steady. GMES and GASK also steady with loops closed. Cavity CFQEA/TDETA was highly unstable. Decided to try and ramp the cavity up a bit using the CRFP readback to keep it tuned and ignoring TDETA/CFQEA.
Recovered the cavity at 6.9 MV/m.
The OPS DRVHs for the following cavities have been updated: 2L14-4
Follow-up Re: Follow-up Re: 1L16 Through 1L20 experiencing CRFP Oscillations
It's the dehumidifier behind Exit Stair 1.
Went out and took a look at NL2 MDP. It also powers the breaker panel inside Exit Stair 1, so I was immediately suspicious. Checked outside the building and, sure enough, there was a dehumidifier. I called the control room and got an estimate for when the oscillations would start again and stood outside by the dehumidifier for that length of time. The dehumidifier turned on and I called the control room back to confirm if the forward power oscillations started again. They had.










