Corey, Elenna, Sheila

Recently we have been having trouble locking DRMI even when the flashes seem good.  We stopped to check some DRMI phasing, similar to what we've done for PRMI in 85080 and 84630. 

The first screenshot shows the PRCL OLG, which has a large wiggle from 20-40 Hz before we started (REFL AIR 9 phase -21).  We ran the template in userapps/lsc/h1/templates/phase_REFLAIR.xml to send a 300 count excitation to PRM M3 at 132 Hz, and phased this into I for REFLAIR 45 (to reduce PRCL cross coupling to the MICH loop), and into I for REFLAIR 9.  Then we checked the TF of PRM to both I sigal to estimate the matrix element we should use to cancel the PRM coupling to the SRCL error signal, and updated this from -1.8 to -1.7. 

These three things have reduced the wiggle.  We are hoping this will help with DRMI acquisition, our first two attempts have gone well but we will wait to collect some statistics.