[Jeff, Daniel]

We cleaned and placed a 6" CF Gate Valve on the South side of the 6 way cross for the Ion Pump. I met with Maty Lesovsky earlier today, and she recommended that after the vacuum system is at a good pressure, we should always keep the ion pump on and just open and close the gate valve as needed. We can indirectly monitor the pressure inside the ion pump's volume with the gate valve closed by looking at the voltage on the output of the ion pump (I have a rough calibration from the LFC, but every pump might be different and I have not kept amazing data for a pressure to voltage conversion). Pressure gauges aren't used by LIGO for this sort of volume, but we have two spare gauges that only go to 1 mTorr and I can't think of a better use for them that to measure the pressure of this volume. I also want to attach an angle valve in case we need to vent this area. We have at least 7 composite angle valves and 5 all metal angle valves (which I've been saving for the RGA attachment points).