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Entry  Tue Dec 30 17:26:23 2014, rana, Update, PSL, Relaxation Osc and the NPRO Noise eater NE_Mephisto.png
    Reply  Fri Mar 13 23:49:28 2015, rana, Update, PSL, Relaxation Osc and the NPRO Noise eater 
Message ID: 11141     Entry time: Fri Mar 13 23:49:28 2015     In reply to: 10848
Author: rana 
Type: Update 
Category: PSL 
Subject: Relaxation Osc and the NPRO Noise eater 

Another thought about the mystery PCDRIVE noise: we've been thinking that it could be some slow death inside the NPRO, but it might also be a broken and intermittent thing in the MC servo or MC REFL PD.

Another possibility is that its frequency noise in the old oscillator used to drive the pre-PMC EOM (which is the Pockel Cell for the FSS). To check this, we should swap in a low noise oscillator for the PMC. I have one for testing which has 36 and 37 MHz outputs.

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