After hard closing corner station beam tube boundary gate valves (GV 5,7) on Tuesday, noticed the pressure at LY went up from ~ 3e-9 Torr to 7e-9 Torr (LX did not rise). A leak, whether external, annulus o-ring, or surface outgassing, has been known for a long time (Kyle made log entries of early {inconclusive} leak hunting). In an effort to troubleshoot, I soft closed GV6 this morning to bound CP1. The pressure at PT-124 (beam tube side of GV6) fell after closing this valve. I will leave it closed for the day to see how the pressure trends, but it looks like there could be a leak somewhere in CP1 or maybe in a flange inner o-ring. Will leak check as time permits.

Unfortunately CP1's pressure gauge has been off since closing valves on Tuesday due to some weird grounding (?) issue with Beckhoff? I reset it but this particular CC is taking a while to turn back on. It is a known problem that when we toggle the LOTO switch on valve, it trips the gauge (x and y side).