Aggregator
CHL2 SCN Status
Summary of events to date
Yesterday, during a sever storm, the SCN 2K cold box tripped.
The system reported multiple problems with Cold Compressor #4 (CC4) magnetic bearing cabinet. The magnetic bearing controls are multi-axis1980's analog control technology.
Operator SIGN IN
backing out of 2L25 Flow Meter measurements
JT & cryo heaters returned to previous configuration
Heaters are ramping back to setpoint at 2 watt/min
Continued 2L25 heat-load measurements. Initial Cavity 8 measurements were taken with the JT fixed at 50%, but cryogenic conditions were unstable. Later testing indicated improved flow-meter and linac-pressure stability when the JT was allowed to regulate within approximately 58â62%, and Cavity 1 measurements were taken under this configuration.
"MCC going to Single SSO and CCoC"
Crew Chief Shift Log, 2026-08-15 OWL
Start of shift: Machine down due to cold box trip.
Crew Chief Timesheet Summary: 15 Aug 2026 OWL
Injector Alarm Limits Set
NLinac/CHL2 Update
Starting Measurements via Flow Meter on Zone 2L25
ATLis:
https://tasklists.jlab.org/atlis/tasks/120026
Given that operations will be down for the night, I'd like to finish taking data points on 2L25-8 as well as take some repeatability measurements across cavities from previous measurements.
JT valve will be manipulated
Heaters will be adjusted
RF will be on
Operator SIGN IN
smartRAT Cavity Instability Detection Daily Report
To view waveforms from a timestamp:
ssh opsrfdaqnl1 "smartRAT -m DAQ -d /data/fast_daq/<timestamp>"
To view waveforms of the top 25 from this report:
ssh opsrfdaqnl1 "smartRAT_view_daily_top25 2026-08-07-2026-08-14"
Data directory: /cs/prohome/apps/s/smartRAT2/pro/fileio/pca_data/output_cavityOutDet/calibrated_cavitylevel_centralize_tsfresh_minimal_gmespmes/whole/rcntnp/2026-08-07-2026-08-14/PCA/
CREW CHIEF SIGN IN
THOMAS JEFFERSON NATIONAL ACCELERATOR FACILITY
ACCELERATOR OPERATIONS CREW CHIEF SIGN IN FORM
Date : 08-14-26
Time : 23:14:15
Day : Friday
Shift : Owl
Crew Chief : Howard
Program Deputy: Park
Team : D
Arm : RADCON
Designated SSO: Price
LERF Operator:
Operators : Price
This stamp certifies that the above Crew Chief has read/reviewed/received the following:
Crew Chief Shift Log, 2026-08-14 SWING
Start of shift: CEBAF down due to NL 2KCB trip










