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Field Emission Measurements 2L24

2 days 12 hours ago
Log Number: 4543806Logbook(s): Entry Makers: dchriBody: 

Scroll to last image for Vacuum & CWWT overview plot

Cavity 1
Limited by max single DecaRad 01 head < 10,000
* I had not realized DecaRad 9 exceeded 10,000 mR/hr until cavity 2 testing concluded
Start GLOS = 2.69
Start GMES = 17.7
Ramp up GLOS = 3.44
Ramp up GMES = 22.3
DecaRad 01 = ~9360
DecaRad 09 = ~12,224 (highest)

Cavity 2
Limited by Admin Limit GMES < 24 MV/m
* I had not realized DecaRad 10 exceeded 10,000 mR/hr until the test began
* Levels reduced quickly once the test began, my hope is that the DecaRad did not become saturated
* DecaRad 10 < 10,000 once cavity 2 = 18.2 MV/m
Start GL

dchri

iocsoftw4spce restored

2 days 14 hours ago
Log Number: 4543804Logbook(s): Tags: Body: restorelib 3.0.1 Target restore date was 2026-08-20 02:28:06 The output from the myRestore execution was as follows: iocsoftw4spce systemEnum@2026-08-20 02:28 2(2) restored Execute: /usr/csite/certified/bin/ced2Epics -ced ced -A -i iocsoftw4spce (success) PVs modified: 0 PVs modified: 0 PVs modified: 0 PVs modified: 0 PVs modified: 0 PVs modified: 0 PVs modified: 0 Procedure return status: Success
alarms

Field Emission Measurements 2L23

2 days 17 hours ago
Log Number: 4543782Logbook(s): Entry Makers: eformanBody: 

Cavity 1: Started at 21 MV/m without quenching. Missed the "config decarad" step...aborted and started again at 21 MV/m.
Cavity 2: Quench >18.9.
Cavity 3: Started at 21 MV/m without quenching.
Cavity 4: Quench >12.7
Cavity 5: Started at 21 MV/m without quenching.
Cavity 6: Quenches above 20.6 MV/m.
Cavity 7: unable to raise gradient much above 20 despite increasing GLOS. Starting at 20 MV/m.
Cavity 8: Started at 24 MV/m

eforman

Operator SIGN IN

2 days 17 hours ago
Log Number: 4543780Logbook(s): Body:  ACCELERATOR OPERATOR SIGN IN FORM OPERATOR:    Christian
DATE:             08/20/2026
SHIFT:               Owl

The operator has read the following:
  • ELOG
  • PD Shift Plan
  • Radiation Surveys for PSS Segments in Controlled Access
  • PSS Log
dchri

Field Emission Measurements 2L05

2 days 20 hours ago
Log Number: 4543776Logbook(s): Entry Makers: eformanBody: 

Cavity 1: Started at 21 MV/m without quenching.
Cavity 2: Started at 21 MV/m without quenching.
Cavity 3: Cavity quenches above 19.7 MV/m (GLOS=3.75)
Cavity 4: Started at 21 MV/m without quenching. Field emission < 10 mRem/h
Cavity 5: Started at 21 MV/m without quenching.
Cavity 6: Started at 21 MV/m without quenching. Field emission < 10 mRem/h
Cavity 7: Started at 21 MV/m without quenching. Downstream vacuum valves closed. Restarted at 20.5 MV/m to completion
Cavity 8: Started at 21 MV/m without quenching.

eforman

COMMENT ON Post SAM FE onset measurements C75 and C100 cryomodules

2 days 23 hours ago
Log Number: 4543770Logbook(s): Body: 

Set up DecaRads on 2L03, 2L05, 2L23 & 2L24.
Pulled DecaRad setups from 1L24 & 1L25.

All chs on all systems read normal background counts after set up.

Measured bias voltage of each chassis locally, to ensure a no-load bias of 0.5v, +/- .005.
Only the 2L24 bias was low; adjusted from 0.483v locally, to 0.510, and back to 0.500.
During this time, ch.10 inexplicably jumped to 6000+ cps, but that is likely just noise from turning the biasing pot.

The Epics readbacks all have slight offsets, but, assuming the channels are still linear, it's likely that the change in voltage, from unloaded tubes

king

Shift Information

Shift Swing
CEBAF Program
MCC Crew Chief Howard
MCC Operators Swing SSO Schaumloffel, Owl SSO Smith
Program Deputy Park
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