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Entry  Tue May 20 16:48:52 2014, ericq, Update, LSC, 3f Stability 3fs.pdfCARMsweepPrcFields.pdf
    Reply  Tue May 20 22:42:28 2014, ericq, Update, LSC, 3f Stability PRCangles.pdf
       Reply  Wed May 21 00:18:40 2014, Jenne, Update, LSC, PRMI locked with REFL33 vs. REFL165 PRMI_outofloop_20May2014.pdf
Message ID: 9978     Entry time: Wed May 21 00:18:40 2014     In reply to: 9977
Author: Jenne 
Type: Update 
Category: LSC 
Subject: PRMI locked with REFL33 vs. REFL165 

Since Q has found that REFL165 will be better for holding the PRMI while we reduce the CARM offset, I had a look at locking PRMI sideband locking with both 3f PDs.

I checked the REFL165 demod phase, and changed it from -142.5 deg to -138.5 deg. to minimize the Q signal while driving PRM length.

I found that keeping the MICH and PRCL loop gains the same, and using matrix elements +0.1 for both I and Q for REFL165, rather than +1 for both I and Q for REFL 33.

MICH gain is +0.8, PRCL gain is -0.02.  FMs 4,5 on for both, FM 2 triggered for MICH, FMs 2,3,6 triggered for PRCL.

I then locked the PRMI on sideband with REFL 33 and then REFL 165, and measured the other one as an out of loop sensor of the motion.  I find that REFL33 and 165 are both comparable, and so we shouldn't have any trouble using REFL165 for locking.


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