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Wed Sep 6 01:09:11 2017, johannes, Update, Computer Scripts / Programs, New set of loss measurements 
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Mon Sep 11 12:56:40 2017, johannes, Update, Computer Scripts / Programs, lossmap attempts
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Mon Sep 11 16:46:09 2017, Steve, Update, PEM, earthquakes
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Tue Sep 19 14:00:41 2017, Steve, Update, PEM, earthquakes
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Fri Oct 27 09:34:20 2017, Steve, Update, PEM, earthquakes
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Fri Nov 10 13:46:26 2017, Steve, Update, PEM, M3.1 local earthquake
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Mon Apr 9 08:39:39 2018, Steve, Update, PEM, M5.3 eq Souther CA  
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Thu Jan 25 08:27:25 2018, Steve, Update, PEM, earthquakes  
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Mon Sep 25 17:56:33 2017, johannes, Update, Computer Scripts / Programs, transmitted power during lossmap
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Thu Oct 11 13:40:51 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Fri Oct 12 12:29:34 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Fri Oct 12 20:20:29 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Sat Oct 13 20:11:10 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Mon Oct 15 10:32:13 2018, yuki, Update, Computer Scripts / Programs, loss measurements 
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Tue Oct 16 00:44:29 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Fri Nov 2 19:25:16 2018, gautam, Update, Computer Scripts / Programs, loss measurements
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Mon Oct 15 12:52:54 2018, yuki, Update, Computer Scripts / Programs, additional comments
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Fri Nov 2 16:42:31 2018, aaron, Update, Computer Scripts / Programs, arm loss measuremenents
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Mon Nov 5 13:52:18 2018, aaron, Update, Computer Scripts / Programs, arm loss measuremenents
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Tue Nov 6 10:19:26 2018, aaron, Update, Computer Scripts / Programs, arm loss measuremenents
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Tue Nov 6 15:23:48 2018, gautam, Update, IOO, IMC problematic
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Tue Nov 6 19:02:35 2018, aaron, Update, IOO, IMC problematic
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Sat Nov 10 17:40:00 2018, aaron, Update, IOO, IMC problematic
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Mon Nov 12 13:53:20 2018, rana, Update, IOO, loss measurement: oscope vs CDS DAQ
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Thu Nov 15 10:21:07 2018, aaron, Update, IOO, IMC problematic 
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Fri Nov 16 10:53:07 2018, aaron, Update, IOO, IMC problematic
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Sat Nov 17 18:59:01 2018, aaron, Update, IOO, IMC problematic
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Wed Nov 7 05:16:16 2018, yuki, Update, Computer Scripts / Programs, arm loss measuremenents
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Message ID: 14269
Entry time: Fri Nov 2 19:25:16 2018
In reply to: 14254
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Author: |
gautam |
Type: |
Update |
Category: |
Computer Scripts / Programs |
Subject: |
loss measurements |
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Some facts which should be considered when doing this measurement and the associated uncertainty:
- When Johannes did the measurement, there was no light from the AS port diverted to the OMC. This represents ~70% loss in the absolute amount of power available for this measurement. I estimate ~1W*Tprm * Ritm * Tbs * Rbs * Tsrm * OMCsplit ~ 300uW which should still be plenty, but the real parameter of interest is the difference in reflected power between locked/no cavity situations, and how that compares to the RMS of the scope readout. For comparison, the POX DC light level is expected to be ~20uW, assuming a 600ppm AR coating on the ITMs.
- Even though the reflection from the arm not being measured may look like it's completely misaligned looking at the AS camera, the PDA520 which is used at the AS port has a large active area and so one must check on the oscilloscope that the other arm is truly misaligned and not hitting the photodiode to avoid interference effects artifically bloating the uncertainty.
- The PDA255 monitoring the MC transmission has a tiny active area. I'm not sure the beam has been centered on it anytime recently. If the beam is not well centered on that PD, and you normalize the measurements by "MC Transmission", you're likely to end up with larger error.
Quote: |
This result has about 40% of uncertaintities in XARM and 33% in YARM (so big... ).
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