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Entry  Tue Dec 4 23:16:35 2007, tobin, Update, PSL, ISS 
    Reply  Wed Dec 5 17:49:57 2007, tobin, Update, PSL, ISS rin.pdf
       Reply  Wed Dec 5 18:22:03 2007, tobin, Update, PSL, ISS dark noise sense_noise.pdf
          Reply  Wed Dec 5 20:32:51 2007, tobin, Update, PSL, ISS dark noise 
             Reply  Thu Dec 6 19:30:43 2007, tobin, Update, PSL, ISS dark noise - 60 Hz! iss.pdf
                Reply  Fri Dec 7 19:14:30 2007, tobin, Update, PSL, ISS dark noise - ground loop enlightenment 
Message ID: 177     Entry time: Thu Dec 6 19:30:43 2007     In reply to: 171     Reply to this: 183
Author: tobin 
Type: Update 
Category: PSL 
Subject: ISS dark noise - 60 Hz! 
A higher resolution spectrum [attached] shows that nearly all of the excess dark noise on the ISS is in 60 Hz harmonics (with some 256 Hz harmonics too--are these from the DAQ?).

With the loop closed and the slider at 5dB, the laser light coming out has a noise floor of 10^-7 RIN or better from 40 Hz to 8 kHz.

Now to figure out why all this 60 Hz is getting in... (I tried turning off all the lights and the HEPA, and moving the SR785 further away, none of which did anything.)
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iss.pdf
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