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 Tue Dec 4 23:16:35 2007, tobin, Update, PSL, ISS
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 Wed Dec 5 17:49:57 2007, tobin, Update, PSL, ISS 
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Wed Dec 5 18:22:03 2007, tobin, Update, PSL, ISS dark noise
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Wed Dec 5 20:32:51 2007, tobin, Update, PSL, ISS dark noise
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Thu Dec 6 19:30:43 2007, tobin, Update, PSL, ISS dark noise - 60 Hz!
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Fri Dec 7 19:14:30 2007, tobin, Update, PSL, ISS dark noise - ground loop enlightenment
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Message ID: 177
Entry time: Thu Dec 6 19:30:43 2007
In reply to: 171
Reply to this: 183
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| Author: |
tobin |
| Type: |
Update |
| Category: |
PSL |
| Subject: |
ISS dark noise - 60 Hz! |
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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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