1. Operational Experience - Field Emission
H&V nested Air Core correctors over BPM
Field emission heats beamline
Vacuum pump faults (1L26)
Vacuum interlock drops zone out of RF
Viewer & pump drop cross
Quad
End of Cryomodule

2. Operational Experience - Field Emission
Cavity Gradients impacting Beamline Vacuum activity
BEAMLINE VACUUM
C Cav 6
C Cav 7
GMES
MV/m

3. Cavity Gradients impacting Beamline Vacuum activity (details)
C Cav 7
C Cav 6

4. Operational Experience - Field Emission
Preliminary information from commissioning
Different from commissioning results
Cavities were not necessarily phased with beam during commissioning
Vacuum activity is more during operations than commissioning
Cavity gradients were lowered to limit the vacuum activity in the zone
Cavities have been running at lower gradients since then
Which means loss of gradient

5. Gradients in C100 During CEBAF Commissioning
Beam measurement when cavities were not phased with the beam
During commissioning cavities were phased with the beam

6. Operational Experience - Field Emission
Valves between C100 cryomodules
Close with field emission activity in a module
If a zone faults
Wait for the vacuum to recover before the zone can be turned on
Loss of beam time
If a zone is recovered before the valve is opened
Zone will fault again once the valve is opened
More time for zone recovery

7. Typical Recovery