Corey, Georgia, Patrick 3 sets of charge measurements have been run for ETMX and ETMY. We have left the IMC_LOCK guardian in AUTO and OFFLINE, the SEI_CONF guardian at SC_OFF_NOBRSXY, and the ALIGN_IFO guardian in AUTO and DOWN. Georgia added step 4a "LHO temporary additional charge measurements in preparation for ion pump/chevron baffle test" to the wiki which we also ran. We tried to run the analyze scripts, but ran into errors that will have to be addressed later.
I have started to analyse the data that we took this morning in the second ETMX measurement, which is a pit-and-yaw oplev measurement as described in alog-42572. The analysis script is in /opt/rtcds/userapps/trunk/sus/common/scripts/quad/opLevChargeMeasurements/analyserChargeMeas.m and the timestamps for this mornings various driven measurements is in rec_LHO/ETMX_0_Hz_GPS_1217087900.txt
The actuation strength numbers are still off by an order of magnitude which I've not managed to reconcile with previous measurements yet.
After discussions with Sheila I added an additional step in the measurement where the ESD signal quadrants are driven longitudinally, giving a measure of the Beta+Beta_2 parameters as driven by the signal electrodes in addition to that driven by the bias electrode. We expect these results to be similar, though we've looked at the ESD patterns and noted that the ESD bias electrode is not symmetric, the bias electrode passes closest to the bump stops (relevant if charge has been deposited after a bump stop collision), and also that the lower quadrant signal electrodes are delivered to the bottom of the optic around the barrel, which possibly has an impact on actuation strength.
Results
Something interesting: when driving the signal electrodes longitudinally there is good coherence with optical lever yaw (.89) but poor coherence with pitch (0.25), while when driving the bias there is good coherence with pitch (.98) and poor coherence with yaw (0.47). I removed results these poor-coherence-measurements from the results matrix above to avoid confusion. There is also strong coherence (~0.9) between optical lever pitch and the excitation when yaw is driven, and vice versa.
We'll try and take these measurements and the usual quadrant-by-quadrant measurements daily in the lead up to the ion-pump revalving in.
Patrick, Georgia
We ran the ETMX charge measurements again this morning.
Quadrant-by-quadrant-Veff:
We only ran 2 repetitions of the old measurement today to minimise inconvenience for other commissioning activities. Results attached
Attachment 1: a single measurement, showing urad of PIT and YAW (as measured on the optical lever) as a function of bias voltage, for a drive to each ESD quadrant. Can also be compared with these measurements of ITMX and ITMY, and this previous measurement of ETMX (which is shown in the second attachment).
Attachment 2: The trend of V_eff over the last few weeks, now with July 31 and August 1 data.
Pitch-and-yaw-4-parameter-measurements:
I reran these this morning as well and got the same results as listed in the table above to within 1 decimal point.