OPLEV charge measurement was performed on ETMX (after Fil switched on the HV at the X-end) this afternoon. The attached plot shows a big spike in the third quadrant for the Pitch: bias voltage is around 65V (up from 25V from last month's measurement). Similarly the third quadrant for the Yaw is at 90V (was at 30V in March).
The other quadrants don't show any increase in the charge accumulation.
I am attaching the ETMX charge measurement results from 2017 taken by J. Kissel after the July 6th 2017 EQ (alog 38401), for comparison. Looking at the trend lines, there doesnt seems to be a significant rise except for the 1st (Yaw) and the 3rd (Pitch) quadrant: bias voltage for them is around 40-50V (which is an increase by 20-30V). The effective bias voltage for other quadrants is below 40V: for Pitch and Yaw.
