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Message ID: 317     Entry time: Mon Aug 30 23:25:06 2010
Author: tara 
Type: Summary 
Category: RefCav 
Subject: RIN comparison between PMC and RCAV 

 I measured RIN from beam behind PMC and RCAV. Photodiodes are connected to SR785 and measured at the same time. 

DC level from PMC and RCAV are 3.56 V and 1.58 V, respectively.

The HEPA filters above the table were turned off during one measurement to see how much it would effect the RIN (turn out to be not that much)

Only PMC and RCAV were locked during the measurement.

The results are plotted together with RIN from 40m's RCAV ( 40m elog. ) PSL has lower noise at lower frequency f< 50Hz, and about 1.5 order of magnitude higher

between 50Hz to 10 kHz. 

I haven't tried to optimize any cavities yet. This is just walk-in,plug-in and measure as a reference for the current setup.

if I try to re-center the beam into the cavities, the result might be better (or worse).

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