Sheila, Louis, Elenna

We have been repeatedly locking fairly well to prep_asc_for_full_ifo. We have set some green references to a decent alignment. However, we have not been able to set the green references to the alignment that we think is best, which we got to after we walked dofs and closed some loops. However, the attached green references get us close enough.

We have successfully closed CHARD, INP1 and PRC2 P and Y. We tried closing MICH P without problems, but closing MICH Y seems to cause problems either by itself or with MICH P. We also starting walking the PRM to bring ADS3 to zero, but only got about a third of the way before a lockloss.

When we did successfully close MICH P, we did so with half gain, this gives about a 0.5 Hz UGF, based on this somewhat sketchy OLG. The design is for 2 Hz, but we think this is ok for now.

I disengaged PRC1 loop in DRMI ASC for now until we know what PRM alignment we will be happy with in full lock. The PRC1 error signal is set by arbitrary offsets on POP A, and we may prefer a different PRM alignment in full lock.

Sheila, Oli, and I took a look at some of our locklosses. We continue to lose lock while sitting in prep_asc, some we can attribute to alignment engagement going haywire, and others we have no reason for. The lockloss tool seems to be tagging many of these locklosses as "IMC" meaning that the IMC is dropping out within 50 ms of the power drop on AS_C. However, Oli notes that the L2 signals of all four test masses seem to be diverging even before the IMC drops out, so maybe this tag is misleading. The behavior of the coil drives suggests that maybe something is going wrong in DHARD P.

Sheila and I found that there are two DARM boosts we could be engaging, that are usually engaged around DARM offset or PREP DC readout. This might help suppress some low frequency DARM motion that DHARD could also be seeing. I moved both of these boosts to DRMI_TO_POP.

As a side note, we successfully used Stefan's "wfsreliefpast.py" script to revert to some good alignment we had when walking full IFO alignment!