Gun off for thanksgiving

• Extractor 5.02 kV current 107.2 uA fil 2.33 A 15 Nov 12
• Gun vac 2.72 e-10 system 1.2e-10 before gun off
• Gun vac drops slightly to 2.27 e-10 while gun runs down 

before restart on Mon 26 Oct 12

• Gun vac 1.1e-10, system 1.3e-10, gun vac fluctuates near zero
• have "column pumping" = pumping, "ready", occasionally off, EHT vac ready = no
• Throttle ion pump, open Ar leak valve to get system pressure 1e-8, try to get SEM ion pressure stable above 1e-10. Not enough, pressure (ion pump current monitor) fluctuates below 1e-10
• Have to open pump bypass, get ion pump pressure ~ 3 e-10 with no fluctuations below 1e-10, after ~ 100 sec stable pressure, EHT vac goes to ready, now start gun run up

Extractor reaches 5020 V at 9:50

9:50  78.4 uA

9:53  83.4

9.56  85.2  also close bypass, gun vac 8.8e-11

10:13  92.3

11:48 105.6 close to steady state

On Tuesday, gun 107.8 uA EHT off, 62 uA EHT on 3 kV, 42.5% extraction