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Message ID: 8464     Entry time: Fri Apr 19 04:20:41 2013
Author: Den 
Type: Update 
Category: Locking 
Subject: PRMI on sidebands 

Tonight PRMI was locked on REFL55 I&Q for PRCL and MICH with POP110I as a trigger and power normalizer.

I could see power fluctuations and beam motion on the POP camera very much the same as for carrier. The difference is that carrier stays for hours while sidebands for a few minutes.

POP110:

I&Q analog gains were set to 15 dB. Relative phase was set to 25 degrees by looking at I and Q components when the cavity goes through the resonance. Q should be 0.

pop_iq.png

REFL55:

Phase rotation was measured by exciting PRM at 20 Hz and minimizing this line at REFL55_Q. I stopped at 33 degrees.

 RIN:

I compared power fluctuations of PRCL when it was locked on carrier (POP_DC) and on sidebands (POP110_I).

rin.png

 

Time series of POP110_I during one of the locks

pop110_i.png

POP camera:

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