We suspect PRM shows significant length to angle coupling due to large oplev beam angle in yaw. Tonight we locked PRCL with ITMs.
We could lock PRCL on carrier to power recycling gain of 15. Lock continued for a few hours but power rin RMS was 0.15.
We triggered and normalized on POP_DC. MICH gain was -1 (filters FM3-5), PRCL gain was -8 (filters FM2,4,5,6,9).
MC_L was OFF during locking.