Sheila, Elenna, Oli

Starting with a quick summary that I will update later.

In short, the problem in DRMI appears to be some cross coupling between MICH and PRCL.

Jenne noted yesterday that the BS M2/M3 crossover seems odd, but I locked MICH dark and PRMI today and checked the BS M2/M3 crossover and it is fine, as is the MICH OLG in both states. However, once we lock DRMI, the MICH OLG and the crossover look strange. We cannot proceed through the DRMI locking process and 3f switch because we can't engage our normal DRMI filters because MICH is not stable.

Our conclusion is that this comes from PRCL because we change the PRCL gain and see a change in the MICH OLG. We also have tried adjusting the phase of the REFLAIR 45 diode and this changes the MICH olg.

I was in the process of moving the phase of REFLAIR 45 and removing the PRCL from REFLAIR 45 Q, but then we realized we had a much bigger problem with ETMX, alog incoming on that later.

Unfortunately it seems the REFLAIR phasing that Jenne and I did yesterday was incorrect because we could not lock PRMI with that phasing. I reverted that phasing, and we have tried going to more positive phase on the diode instead, which is also helping.

It would be good if we could decouple PRCL and MICH. After that, I think it would be helpful if we could increase the MICH gain and bring the UGF closer to 15 Hz. Sheila and I think we can bump SRCL up to 35 Hz.