Sheila, Georgia, Dan, Alexei, Nutsinee, TVo
We found it odd yesterday that we needed to move PRM ~100urad in pitch and ~50urad in yaw to get PRX fringes from Feb 8th. Sheila walked back PR2 a bit to get PRM back to where we were and this centered the beam onto the refl camera, which is good. At this point we should have seen the beam on AS_C in HAM6 because everything seemed to be the same, however, Georgia noticed the witness sensors on SR3 M3 were much different than Feb 8 even though the alignment sliders were the same, this was due to an alignment dither offset on M1 that was still on. Once this was turned off, we got a beam on AS_C.
Then we proceeded to HAM6 and were able to find a leakage beam on the squeezer side hitting ZM2, however, it seemed low in pitch coming out of HAM5 and not possible to coalign with the current Squeezer optics. This was not correctable with ZM2 (railed) alone so we're in a tough position here to see *maybe* correcting the squeezer beam without jeopardizing the IFO to OMC alignment. Sheila felt it was worth trying to nail down how much we can actually change the SR optics before clipping on the OFI, so we set out to try to find an edge of the OFI aperture by slowly moving SR3 in pitch while compensating with SR2:
| SR3 Pit Alignment slider | SR2 Pit Alignment slider | |
| -60 | 4000 | |
| +1100 | -3557 |
This means that SR2 has the full range of pitch before we start falling off AS_C while compensating with SR3.
Now, If we then center on nominal with SR3, then the SR2 range is
| SR3 Pit Alignment | SR2 Pit Max | SR2 Pit Min |
| 520 | 487 | 212 |
Based off our data, tomorrow, we'll go into chamber and see if it's possible to correct the ifo to squeezer alignment without clipping on the OFI.
