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Message ID: 5956     Entry time: Sat Nov 19 00:47:24 2011
Author: Zach 
Type: Update 
Category: Green Locking 
Subject: Y-Arm locked with PDH Box #17 

I installed the newly modified PDH box #17 and locked the Y-Arm.

I wasn't able to bring the REFL level down to the 30% that Kiwamu claimed to get, despite readjusting the alignment---I got ~40-45%. I attained a UGF of ~8 kHz, lower than the 20 kHz that Kiwamu said he got with the temporary setup, probably because the PDH box just isn't as fast. Despite that, it looks like the error suppression is actually better than before...

Here is an error spectrum:


I have to admit that this calibration is worthy of suspicion and should be done more rigorously. I simply used the measured UGF frequency and known servo TF and PZT actuator gain to estimate the optical response. I am pretty confident that it's accurate to within a factor of 3 or so.

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