georgia.mansell@LIGO.ORG - posted 15:07, Monday 05 February 2018 (40422)
Manual A2L decoupling for IMC spot position
[TVo Jenne Sheila Georgia]
We have recalculated the spot positions on the IMC optics (MC1, MC2, MC3), following the method from alog-31402. We dithered the pitch and yaw of each mirror, and minimized the presence of the dither in the error signal by adjusting the pitch-to-length (P2L) and yaw-to-length (Y2L) coefficients in the drivealign matrix of each mirror. From these coefficients we can work out the alpha coefficient (as in OMClog-2863), and from this the spot position on the mirror.
| P2L or Y2L coefficient | alpha | spot position* [mm] | |
|---|---|---|---|
| MC1 p |
-0.2 |
-0.00955 | 0.403 |
| MC1 y | -0.4 | -0.0191 | -0.806 |
| MC2 p | -2.05 | -0.0978 | 4.129 |
| MC2 y | 0.55 | 0.0262 | 1.108 |
| MC3 p | -0.25 | -0.0119 | 0.503 |
| MC3 y | -0.42 | -0.0200 | -0.846 |
*spot position relative to center of mirror, face-on.
Overall these positions are closer to the center of all of the optics compared to what was measured for O2.