J. Kissel, J. Worden, K. Ryan

Just picking up the ball from Borja's charging measurements -- I wanted to be sure I understood the current status of the vacuum before I got started. I attach minute trends the past 100 days of the end-station ion pumps. We expect and understand the behavior seen in ETMX, but only the B channels on EY appear to be reporting sensible information.

Current Status:
H1 EY
   Ion Pump valved IN (gate valve on IP-11 is open to the chamber)
   Turbo pump is valved OUT (closed to chamber)
This status has been the same since Tues Aug 26 13606.

Remember, each ion pump has two circuits, A and B, of which we monitor (in EPICs) both Current (I, in [A]) and the Electric Field (E, in [kV]). It looks like, at EY, these monitor signals for circuit A are broken -- both I and E channels are reporting what appears to be an *inverted* current signal. The B channels make sense, in that the current matches the expected behavior (current [proportional o pressure] is low when valved out [closed to the chamber, pumping on a small volume], high when valved in [open to the chamber, pumping on a large volume]). What's also curious is that the B channel's field is at a roughly constant 7 [kV], where as for EY A , EX A and B, they're consistently 3 [kV]. John is reasonably confident that this is a problem with the monitors, and not indicative of any problems with the ion pumps.

H1 EX
   Ion pump valved OUT (gate valve on IP-12 is closed to the chamber)
   Turbo pump is valved IN (open to the chamber)
EX had had failure trouble with several of its B circuit's power supplies, which is why one sees changes between 2014-Jul-20 and 2014-Aug-23. The log indicating the fix is LHO aLOG 13566.