GTS meeting 5 02 17

Down Monday - Wednesday. Plan to:

1. Degas dump with NEGS at 25% on for ion pumps to take vacuum load
2. Replace ND filter from ND1 to ND3
3. Re-activate photocathode with 3 mm active area
4. Instrument wire scanner
5. Install WiFi access point and enable JMenu on PC in GTS cave
6. Why is Dump/FC reading -20 nA?
7. Hi-pot VIPGT06
8. SCAM VL LINE SYNC frequency is not 60 Hz?
9. Put ND filter in front of ITVGT06 and mount camera on the floor.

Attempts to run at 1 m

1. Ran for few seconds before a HV arc. QE dropped by a factor of 2.
2. Ran again for 1.5 hours (with ion-precipitators on) before a HV arc. QE dropped by another factor of 2.

Ion Precipitators

1. ion collectors and anode current
2. The downstream ion collector was wired incorrectly
3. This is a sketch of the internals of the downstream ion collector VICGT06
4. 
5. These are Cornell's results
6. 
7. Grames paper on anode bias: Media:Grames_PST07_final.pdf
8. Pozdeyev PAC 2007 ion trapping: Media:Pozdeyev.PDF
9. Cornell PRAB paper on ion clearing electrodes: Media:Cornell ion colelctors PhysRevAccelBeams.19.034201.pdf
10. Gabriel's calculation (POISSON model) of the voltage needed in upstream ion collector (VICGT04, wire sticking out of the spool piece): Media:Ion collector VICGT04 wire stikcing out of spool piece.pdf
11. CEBAF vacuum during 1 mA run
12. 
13. GTS vacuum 1 mA run April 28 2017
14. 
15. GTS 1 mA run also tripped 1.5 hour July 11 2016
16.