Gerardo M., Kyle R.

GV1 has a known inner O-ring leak on the Vertex-side flange.  As such, its AIP can't handle the added gas when the Vertex volume gets vented and it will go off scale as a result.  Today's venting of the Vertex volume was no exception.  However, unlike previous precedence, we are now routinely combining the gate annulus volume with the adjacent annulus volume whenever we close large gate valves (a.k.a. "GVs" - in this case, GV1).  We have adopted this change so that the gate volume will get pumped by the GV's AIP during those periods when the GV is closed.  The benefit of doing this is that we, now, don't need to connect pump carts to GV's to pump out the gate volumes after the GV's have remained closed for long periods (days) and this is a significant time/effort savings.  The downside is that we now have to remember to re-isolate the gate annulus volume before the GV gets opened.  We keep the gate annulus volume isolated from the adjacent AIP-side annulus volume when a GV is open as a layer of protection of the BT should we need to vent the AIP-side of a given GV as part of replacing its ion pump (not an uncommon service).  If we didn't remember to isolate the gate annulus volume before venting the AIP-side we would then vent the Beam Tube by accident.  Its all very stressful and confusing.  Just be happy that you aren't in the Vacuum group! ;)

Following today's brief venting of the Vertex, we now have an unknown amount of gas in GV1's annulus volume which includes the gate annulus.  As such, Gerardo and I connected a pump cart and evacuated the entire annulus volume so as to eliminate the possibility of dumping ??? torr*L of air into the BT when we next open GV1.