Attached is a 60 day trend of PT140 which is a one of the new Inficon BPG402s? IP7 and IP8 have been a steady 5000 volts for this time period. Is this a gauge thing? I haven't been intimate with what Gerardo, John and Chandra have learned regarding the behavior of these new wide-range Bayard-Alpert/Pirani hybrids but this slope looks "not insignificant"
That slope looks really fishy. Are both IPs fully pumping? What does HAM6 pressure look like (also hot cathode ion gauge)? Did PT 170 and 180 flatten out after degassing?
We think that the pressure increase is due to temperature, see attached. aLOG noting temperature change.
Since we are talking temperature change in the LVEA, note the vertical change on some of the optics (BS and ITMs), other are affected as well.