There was another pressure spike in HAM6 volume this morning at ~4:28:35 am PDT. The total rise in pressure in HAM6 is 1.15E-8 Torr. This pressure rise was also seen in BSC2 (PT120B), where the total pressure rise was ~3E-10 Torr. See attached plot. Top channel is BSC2 PT120B gauge, middle plot is HAM6 (PT110) and the bottom is the IFO lock state, where -10 is equal to IDLE, so this does not correlate with any lockloss.

Looking at the RGA on the Output tube, there is a small bump in AMU 28 at the same time as the pressure spike, see 2nd attachment. The blue trace on the bottom plot is AMU28 ion current for each 5ms dwell time scan (0-100), so not a true MID scan. Using PT120B as a quick calibration for the RGA at the time just before the pressure rise (P~8E-9 Torr) , and AMU 2 & 18 ion current (Sum~8E-9 amp). Calibration is ~1 to 1. The AMU28 rise is ~2E-10 Torr. Typical HCs (41, 43, 53, 55, 57) had no significant change and similarly for argon (AMU 40), so this does not seem to be argon instability of the ion pumps.