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40m Log |
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Mon Mar 19 23:44:00 2018, gautam, Update, IOO, IMC loop checkup 
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Tue Mar 20 16:53:03 2018, gautam, Update, IOO, IMC loop checkup
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Tue Mar 20 21:08:03 2018, gautam, Update, IOO, IMC loop checkup
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Tue Mar 20 22:44:45 2018, gautam, Update, IOO, IMC loop checkup
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Wed Mar 21 15:52:45 2018, gautam, Update, IOO, MC error point calibration  
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Wed Mar 21 17:31:21 2018, gautam, Update, IOO, MC error point calibration
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Wed Mar 21 21:13:44 2018, gautam, Update, IOO, IMC noise budget
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Tue Mar 27 01:39:44 2018, gautam, Update, IOO, PSL noise eater was off
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Tue Mar 27 19:32:03 2018, arijit, Update, IOO, PSL noise eater was off 
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Tue Mar 27 23:37:35 2018, gautam, Update, IOO, MC REFL PD removed
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Wed Mar 28 21:31:39 2018, gautam, Update, IOO, MC REFL PD removed
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Wed Mar 28 21:47:37 2018, arijit, Update, IOO, MCREFL_PD Optical response measurement 
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Thu Mar 29 17:57:36 2018, arijit, Update, IOO, MCREFL_PD Optical response measurement
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Fri Mar 30 06:14:31 2018, rana, Update, IOO, MCREFL_PD Optical response measurement
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Fri Mar 30 22:37:36 2018, Kevin, Update, IOO, MCREFL_PD Optical response measurement
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Thu Apr 5 04:36:56 2018, Kevin, Update, IOO, Coil driver noise  
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Thu Apr 5 12:13:18 2018, Koji, Update, IOO, Coil driver noise
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Fri Apr 6 21:39:09 2018, gautam, Update, IOO, MC2 suspension health checkup
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Mon Apr 9 18:46:03 2018, gautam, Update, IOO, Further debugging 
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Tue Apr 10 14:28:44 2018, gautam, Update, IOO, Further debugging
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Wed Apr 11 01:34:31 2018, gautam, Update, IOO, Activities today
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Thu Apr 12 18:12:49 2018, gautam, Update, ALS, NPRO channels hijacked  
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Fri Apr 13 11:02:41 2018, gautam, Update, ALS, EX fiber polarization drift
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Fri Apr 13 17:56:26 2018, gautam, Update, ALS, Fibers switched out
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Sat Apr 14 14:42:09 2018, gautam, Update, ALS, Fibers switched out
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Tue Apr 17 14:08:29 2018, gautam, Update, ALS, Fibers switched out
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Fri Apr 20 00:26:34 2018, gautam, Update, ALS, Fibers switched out
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Sat Apr 21 20:25:12 2018, gautam, Update, ALS, PSL fiber pickoff status
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Thu Apr 19 00:03:51 2018, gautam, Update, IOO, More IMC NBing 
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Thu Apr 19 17:15:35 2018, gautam, Update, IOO, More IMC NBing 
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Sun May 20 23:43:50 2018, gautam, Update, IOO, Coil driver noise re-measurement    
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Tue May 22 17:26:25 2018, gautam, Update, IOO, MC1 Coil Driver pulled out
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Tue May 22 23:28:01 2018, gautam, Update, IOO, MC1 Coil Driver pulled out
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Wed May 23 17:58:48 2018, gautam, Update, IOO, MC1 Coil Driver pulled out 
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Wed May 30 10:17:46 2018, gautam, Update, IOO, MC1 Coil Driver pulled out 
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Fri Apr 6 22:23:53 2018, Kevin, Update, IOO, Coil driver noise
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Message ID: 13728
Entry time: Thu Apr 5 04:36:56 2018
In reply to: 13698
Reply to this: 13730
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Author: |
Kevin |
Type: |
Update |
Category: |
IOO |
Subject: |
Coil driver noise |
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[Gautam, Kevin]
We measured the MC coil driver noise at the output monitors of the coil driver board with an SR785 in order to further diagnose the excess IMC frequency noise.
Attachments 1 and 2 show the noise for the UL coils of MC3 and MC2 with various combinations of output filters engaged. When the 28 Hz elliptic filter is on, the analog dewhitening filter is off, and vice versa. The effect of the analog low pass filter is visible in MC3, but the effect of the digital low pass filter is swamped by the DAC noise.
We locked the arms and measured the ALS beatnote in each of these filter combinations, but which filters were on did not effect the excess IMC frequency noise. This suggests that the coil drivers are not responsible for the excess noise.
Attachment 2 shows the noise for all five coils on MC1, MC2, and MC3 as well as for ITMY, which is on a different DAC card from the MCs. All filters were on for these measurements.
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