Georgia, Keita, Craig
After Hang and Gabriele walked PR3 in yaw, this altered the green and POP alignment onto ISCT1.
We moved PICO A (controller 3) Motor 8 (ALS/POP steering HAM1) -100 in relative X position.
This put the ALS beams on the left side of the two inch periscope, and required us to move the prism and all downstream optics aligning onto TRX, TRY, COMM, and DIFF. COMM beatnote this morning was -5 dB, DIFF was -13 dB. Now COMM is -6 dB and DIFF is -6.5 dB.
Moving the picomotor alleviated Y-arm clipping somewhere in the HAM3 to ISCT1 ALS path, now our ALS_Y camera looks much better, and is not obviously scattered onto the ALS_X path. (Picture 1)
After fixing ALS, we planned to lock the full IFO however we could, return to Hang and Gabriele's optic positions, then return to ISCT1 to fix POPAIR. But this was not needed: the picomotor move ended up fixing the POPAIR alignment for us.
To return to Hang and Gabiele's alignment, we used Stefan's WFS alignment script in userapps/trunk/asc/h1/scripts. I ran python wfsreliefpast.py 1220391638, and all the main optics were brought back to where they were when they achieved higher power recycling gain.
We then touched up DRMI by hand, aligning PRM and BS so that POPAIR B was maximized like usual. We were able to lock Full IFO and get PR gain of 38 like this morning.
I was worried that after touching the picomotor we'd be falling off POP_A_LF. That is not the case (Pic 4).
We got back to the ENGAGE_SOFT_LOOPS state and continued to adjust PR3 towards negative yaw, getting even more gains, up to 38.7, first attached figure.
As we adjusted PR3 the ALS became misaligned on ISCT1 again, visible on the cameras and on the transmission DCPDs. Second attachment shows the DCPD outputs. X-arm walks off the diode and Y-arm sees more light, suggesting the beam is moving to the right on the prism (as viewed from the door to ISCT6). To reconcile the green and IR alignments we will need to pico again as described in Craig's post, but we did not get to this tonight.
We did not update the camera references, but the third attachment shows the beam position with the *inital* PR3 alignment we had at the start of the other screenshots, i.e. PR3 yaw = 247.8.
At 06:16:30 we had a lockloss that seemed to be due to a lightning strike. We've been consistently losing lock at the CARM_5_PICOMETERS state for a while now, time to call it a night.
When you moved again PR3, were the A2L coefficients of the ITMs off as we left them? If so, the demodulated dither lines values (~3 and ~10) show a large improvement (they were ~15 with the A2L off when we finished moving PR3 before the table realignment.
We also noticed that POPX PZT were railing and POPX WFS were not centered. Is it working now? If so, this explains why you were able to gain more power after the realignment, while we were clearly hitting a maximum before.
I forgot to set the A2L coefficients, so they were whatever they are after we've cycled through the down state. The ADS demod signal for one of the itms was around 4 and the other was around 10 *before* we'd done any PR3 touch-ups.
PRX was no longer railing, and the buildups on POPAIRB were still looking ok (I think by the time I'd moved the PR3 slider to 245 in yaw we were starting to lose POPAIRB again though). We suspect when we pico'd the ALS beam onto ISCT1 we also fixed the pop path, I think that's the only explanation for why POPX would be no longer railing.