Jennie W, Sheila
After our picoing efforts, at 22:50 UTC today Sheila and I measured the A2L gains of the SRM and SR2.
Sheila notched 31 Hz out of the SRCL control loop and I injected a line at this frequency first at SUS-SRM_M3_LOCK_P_EXC, then SUS-SRM_M3_LOCK_Y_EXC.
Sheila changed the A2L gains for the corresponding degree of freedom so that the line height was minimised in SRCL_IN1 and in DARM using the channels H1:SUS-SRM_M3_DRIVEALIGN_P2L_GAIN and H1:SUS-SRM_M3_DRIVEALIGN_Y2L_GAIN.
SRM spot position:
P2L -1 with precision of 1
Y2L 6 with a precision of 0.5
(not too sure of the precisions as I lost my alog halfway through (d'oh).
We then did the same thing for SR2 by injecting in the M3_LOCK P and Y channels and changing the DRIVE ALIGN gains for SR2.
SR2 spot position was
Y2L 1.5 with precisioon of 0.25
P2L is 8 with precision of 1
The templates for these measurements are in: /ligo/home/jennifer.wright/Templates/Measure_spot_size_SR2.xml and Measure_spot_size_SRM.xml
Sheila and Keita have recently found and fixed sign convention errors. Please see alog 78393 for the corrected interpretation of A2L gains to inferred spot positions.
At the request of Alena, here's a table of M1 OSEM P and Y INMON for the output optics right after A2L measurements (starting ~2024/Jun/06 23:10:00 UTC):