Summary:

1. CARM offset was reduced to 0 with the PRMI locked.
2. TRY levels touched ~200 (Recycling gain ~10, IFO is still undercoupled).
3. TRX level never went so high - I suspect QPD issues or clipping in the beampath.

Details:

• Attachment #1 is a StripTool summary of the lock - encouragingly, the PRMI stayed locked for several 10s of minutes even when the CARM offset was brought to 0.
• The MICH signal was pretty glitchy - we increased the gain of the MICH and PRCL loops and thought we saw some improvement, but needs more quantitative investigation.
• Main differences in locking procedure today were:
  • Added some POPDC to the MICH/PRCL trigger elements in addition to POP22
  • Tried adding a DARM offset before doing the final steps of CARM offset reduction, and then zerod the DARM offset too.
• The TRX level never went as high as TRY - even though on the CRT monitors, both arms seemed to saturate somewhat more evenly. Potentially the EX QPD needs a checkout, or there is some clipping in the in-air TRX path. Although, puzzilingly, the POXDC level never goes as high as POYDC either. So maybe the buildup is really lower in the XARM? For the daytime tomorrow.

Next steps:

1. Check the EX QPD / TRX situation.
2. Figure out how to make the PRMI lock more stable as I reduce the CARM offset.
3. Start figuring out the CM board, as we'd want to do the handoff to RF at some point.