cheryl.vorvick@LIGO.ORG - posted 11:06, Friday 13 December 2013 - last comment - 19:39, Sunday 26 March 2017(8943)
IMC beam spot centering measurement - all beam spots within 2.3mm of center.
I calculated the spot centering on the IMC mirrors, with help from Kiwamu and Jax (alog #6676).
All beam spots are with 2.3mm on center on all 3 mirrors, which is slightly better than what Jax measured in June.
| Beam Centering Measurements: 12/12 | P2L/Y2L gain | smallest peak amplitude | EL/EP | alpha | alpha in % | distance from center of mirror, in mm |
| 0.25/5.2382 | (EL/EP)*P2L/Y2L gain | % * 0.375 | ||||
| MC1 | ||||||
| P | -0.90 | 0.05 | 0.048 | -0.043 | -4.3 | -1.6 |
| Y | 0.60 | 0.30 | 0.048 | 0.029 | 2.9 | 1.1 |
| MC2 | ||||||
| P | -1.30 | 0.05 | 0.048 | -0.062 | -6.2 | -2.3 |
| Y | -1.00 | 0.50 | 0.048 | -0.048 | -4.8 | -1.8 |
| MC3 | ||||||
| P | 0.85 | 0.12 | 0.048 | 0.041 | 4.1 | 1.5 |
| Y | -1.10 | 0.05 | 0.048 | -0.052 | -5.2 | -2.0 |
I'm revisiting beam centering measurements, and have recalculated the beam centering logged here, based on my enhanced knowledge, and with both the procedure used in 2013 and in 2017.
My sign conventions in this 2013 alog are incorrect, and I'm now correcting them, and posting values using both the 2013 and 2017 procedure.
In 2013, though it's not stated, I used the Eul2OSEM values that match the UR OSEM, which matches the procedure I used in 2017, alog 34973
Updated Results (details in attached pdf):