Jenne, Hang, Georgia, Craig

Today we locked DRMI with 1.4 watts laser input power

The NPRO replacement crew gave the commissioning team 1.4 watts of input power to the interferometer as they considered what to do next regarding the poor NPRO beam shape quality.  We set to work aligning the corner while Keita focused on ALS prep for a potential peek down X-arm on Thursday, given no NPRO work that day.

1) We locked the IMC, and measured the IMC beam spot positions using a2l_min_IMC.py and the new alpha to mm values.  Our spot positions are significantly different from when Sheila measured the IMC spot positions on June 5th.
LL is the reference coil, meaning negative alphas mean the beam is closer to LL than center, etc.  Also note that the old spot positions used the old HSTS alpha to mm estimate, which was about 7% bigger.

          MC1 P     MC2 P     MC3 P     MC1 Y     MC2 Y     MC3 Y
alpha     0.0024    0.0172    0.0092    0.0060    0.0021    0.0262
mm        0.0937    0.6745    0.3629    0.2338    0.0838    1.0311

IMC beam spots seem better now than in June.

2) We then locked MICH, PRX, PRMI, and DRMI.  We started by going back to our alignment from June 21 and touching up alignment by hand.  Our new alignment is posted below.  This should be good enough prep for a look down X-arm on Thursday.  

3) We started closing ASC loops.  We were able to close MICH, INP1, PRC2, SRC1 and SRC2.  Trying to close PRC1 we lost lock.  After we lost lock, reacquiring DRMI was hard and unstable.  We suspect our alignment is pretty bad, so the ASC loops were probably doing a lot of work the first time we acquired and we never offloaded to higher stages.  We resorted to locking PRMI by itself, which was stable, then transitioning to DRMI.

4) SRM is completely railed with DRMI locked.  We took a look at the SRCL loop, the error signal seems okay but the control signal is insane out of H1LSC_SRCL1.  There is an engaged offset of -800, an engaged integrator in FM4, and a gain of -45, yielding a massive control signal which railed the M3 and M1 stages of SRM.