To check the results from my ETMX electrostatic co-efficient measurements (alog 42572) I ran the usual optical lever V_eff measurements. The results show roughly 0 to -20V on all quadrants, which is the same ballpark as I measured earlier this week.

I'm attaching a plot of the V_eff trends since September 2016 (first attachment), a zoomed in plot of the new data (second attachment), and one of the five plots that the ESD_Night_ETMX.py script spits out, showing optical lever transfer function as a function of effective bias (third attachment). We can do more with this data than just work out Veff: from the TF value at V_bias = 0V we can work out Beta-Beta_2, and from the slope we can work out gamma - alpha.