Aggregator

Log Number: 4475284Logbook(s): 

• ELOG

Entry Makers: deirBody: 

Reset masking to Injector 500keV.

Opened up VBV0I06 to clear FSD. Closed the valves around the booster. The 0I06 valve was closed as a precaution to protect the booster. Since we are back to being limited to Mode 0, the booster RF cannot be turned on so there is no issue with keeping those valves closed.

Log Number: 4475283Logbook(s): 

• ELOG

Tags: 

• Autolog

Body: saver ran from opsl632

Saved: samari 03-10-26 05:02:15 {A:i B:5 C:2 E:345 A=BS B=BS C=BS D=BS 0R08=0.00 0R08 dump in. Autosave prior to restore.

Log Number: 4475282Logbook(s): 

• POLOG
• ELOG

Entry Makers: samariBody: 

At the request of CIS, I'll begin threading viewer limited beam to 1D. First, I'll load all save #25231 from the 2024 as mentioned in the linked log.

Log Number: 4475281Logbook(s): 

• ELOG

Entry Makers: deirBody: 

Gun is on at 140 kV and CIS has given permission to run viewer limited beam only.

Log Number: 4475280Logbook(s): 

• ELOG

Tags: 

• Autolog

Body: Destination Masking to: Inj500KeV
User: deir

Log Number: 4475279Logbook(s): 

• POLOG
• ELOG

Entry Makers: msmithBody: 

Moved the MBO0I06 slider until the INJ dropped to power permit, as expected

Log Number: 4475278Logbook(s): 

• POLOG
• ELOG

Body: 

QE Scan (max QE = 1.26%):
https://logbooks.jlab.org/entry/4475275

Log Number: 4475276Logbook(s): 

• POLOG
• ELOG

Entry Makers: suleimanBody: 

Vacuum is Ok to open valves.

Log Number: 4475272Logbook(s): 

• POLOG
• ELOG

Body: 

The SLSP-5247-4 GaAs photocathode mounted on puck #3 has been activated with 15 yo-yo's (5 mm mask). The puck has been inserted in the gun with the ear at about 15 degrees CCW from the vertical direction (same angle as before). At the long manipulator, this corresponds to 25 degrees.

The HV bias was set to "5" on the battery box. The picoammeter was set 200 nA Full Scale then 2 uA after the second yo-yo.

The Cs was heated with 4.6 A (0.98 V) and vacuum went to 9 nA. The first QE Cs peak started to show up after 14 minutes.

Log Number: 4475271Logbook(s): 

• ELOG

Entry Makers: samariBody: 

Fig one shows its been steadily rising since early February, but now its averaging at 85 and spiking to 100 (fig 2)

Log Number: 4475270Logbook(s): 

• ELOG
• POLOG

Body: 

Heated puck # 3 in oven and soaked between 500 and 509 C for 30 minutes. Heater at 8.7 Amp and 3.95 V. Vacuum went from 0.4 nA to 72 nA. When stopped soaking, degassed Cs source at 4.7 A for 10 seconds; vacuum went from to 42 nA to 100 nA.

Log Number: 4475269Logbook(s): 

• ELOG

Entry Makers: samariBody: 

17 hours ago at around 8:05, the exit stair 4 dehumidifier was turned off to verify that it was the cause of the detuning. We see that when it is turned off it has a massive effect. While it was on, we saw many cavities frequently hitting their step limit of 50k (middle graph in Fig 1). Afterwards, the cavities are tuning regularly and have consistent forward power (fig 2).

It would be really helpful to do this same exercise with the exit stair 1 dehumidifier, as we see the exact same issue happening in zones 1L16:1L21.

Log Number: 4475268Logbook(s): 

• ELOG
• RFLOG

Tags: 

• Autolog

Body: 

The following cavity histories have been updated:
2L08-3
Username: samari
Date/Time: 03-10-26_00:17:32
RF Status: Good
Tuner Status: Good
Comment: RF Recovered, see log 4475130
Special Instructions:

Maintenance Tag: Component: Operator Entry - See SME

Log Number: 4475267Logbook(s): 

• ELOG
• LERFLOG

Body:  ACCELERATOR OPERATOR SIGN IN FORM OPERATOR:    Smith
DATE:             03/10/2026
SHIFT:               Owl

The operator has read the following:

• ELOG
• PD Shift Plan
• Radiation Surveys for PSS Segments in Controlled Access
• PSS Log

Log Number: 4475266Logbook(s): 

• ELOG
• LERFLOG

Body:  ACCELERATOR OPERATOR SIGN IN FORM OPERATOR:    Samari
DATE:             03/10/2026
SHIFT:               Owl

The operator has read the following:

• ELOG
• PD Shift Plan
• Radiation Surveys for PSS Segments in Controlled Access
• PSS Log

Log Number: 4475265Logbook(s): 

• ELOG

Entry Makers: alexsBody: 

Current suddenly dropped to 0 and voltage increased ~1 V. Jostling the current setpoint woke it back up.

Log Number: 4475263Logbook(s): 

• ELOG
• LERFLOG

Body: 
THOMAS JEFFERSON NATIONAL ACCELERATOR FACILITY
ACCELERATOR OPERATIONS CREW CHIEF SIGN IN FORM

Date : 03-09-26
Time : 23:02:02
Day : Monday
Shift : Owl

Crew Chief : Deir
Program Deputy: Schoene
Team : A
Arm : Smith
Designated SSO: Samari
LERF Operator:
Operators : Samari, Smith

This stamp certifies that the above Crew Chief has read/reviewed/received the following:

Log Number: 4475262Logbook(s): 

• ELOG
• SRFLOG

Body: 

Set out to confirm FE measurements for Cavities 1 and 3.
Cavity 3 appears to have popped a new field emitter (?) at some point. Found FE onset at 6.2 MV/m and the cavity quenching at ~11 MV/m after running at 18 MV/m on Friday. No event today that might signify a new field emitter. Cavity gradient was very unstable in both SEL and
Pulsed. Gradient would randomly start drooping. And towards the end of the new one hour run at 10.5 MV/m, the gradient began stepping up and down by several MV/m.

Log Number: 4475261Logbook(s): 

• ELOG
• RFLOG

Entry Makers: alexsBody: 

RFCM lost comms and dropped high voltage (figure 1,2). A local reset brought it back to life, and recovered HV and RF. Listing this as an OPS-PR for RF SME review and because there is a lingering limit fault on the comms screen I have forgotten how to clear (figure 3). No other steps with the RFCM were taken besides the local reset.

Log Number: 4475258Logbook(s): 

• CLOG
• ELOG

Entry Makers: johnwBody: 

Around 7:00pm, 2L25 dropped into its low level alarm. This appears to be due to RF starting up. The liquid level has come back up to near its normal, but is less stable than before. The JT valve responded as expected, and no other issues are noted.

Note: The LEM value and/or the REQ Heat Watts for this cryomodule may need to be adjusted.