J. Kissel, D. Barker
FRS Ticket 8218

Executive summary:
Charge measurements complete after having "restoring" the "broken" infrastructure to do so. Charge looks OK, but not great. 

Details:
After a few weeks of work, Dave was unable to identify any problems with the charge measurement scripts originally reported in LHO aLOG 36338.

So, today, we just tried running the scripts again, and it worked. #facepalm
Our best guess is that what error was reported was a bogus error, and the real problem was a result of NDS2 upgrades vs. Debian OS upgrades that were going at the time. It's a shame we didn't try at any other point during the interim weeks.

Anyways, here are the latest charge measurements. 

Recall that we had tried some level of charge mitigation during the May 8th commissioning / vent period in hopes to reduce / turn around the ETMY accumulated effective bias voltage from ~40-50 [V]. We appear to have paused this accumulation, at least from what little data we have thus far. Another contributing factor may be that our duty cycle has been substantially less since the vent, so I imagine that we've had more time with the opposite signed bias voltage that also will have helped. Thus, I think we're essential picking up right where we left off before the vent, where it's on the borderline of being concerning, but not requiring immediate action just yet.

Remember that this technique reports the angular actuation strength per quadrant, and not the longitudinal actuation strength. I normal post the longitudinal relative actuation strength via the calibration lines from the summary pages but
- The summary pages are down, 
- We changed our computation of the time dependent correction factors to PCALY TXPD today, so the results may be skewed, and
- We've had no new nominal low noise lock stretches since that change
I'll attach a comment later that shows how the longitudinal actuation strength is doing. However, Aaron's plot in LHO aLOG 37158 shows that the accumulation is ~4% or so, again, we're in the same boat as before the vent. 

ETMX appears to have continued to keep a low effective bias voltage accumulation.