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40m Log |
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Thu Jan 4 12:46:27 2018, gautam, Update, ALS, Fiber ALS assay 
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Thu Jan 11 14:22:40 2018, gautam, Update, ALS, Fiber ALS assay
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Thu Jan 11 20:51:20 2018, gautam, Update, ALS, Fiber ALS assay
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Tue Jan 16 21:50:53 2018, gautam, Update, ALS, Fiber ALS assay
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Thu Jan 18 00:35:00 2018, gautam, Update, ALS, Fiber ALS assay 
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Fri Jan 19 11:34:21 2018, gautam, Update, ALS, Fiber ALS assay
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Fri Jan 19 23:04:11 2018, gautam, Update, ALS, Fiber ALS assay
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Wed Jan 24 00:33:31 2018, gautam, Update, ALS, Fiber ALS assay
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Wed Jan 24 10:45:14 2018, gautam, Update, ALS, Fiber ALS assay
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Thu Jan 25 23:59:14 2018, gautam, Update, ALS, Fiber ALS assay
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Fri Jan 26 20:03:09 2018, gautam, Update, ALS, Fiber ALS assay
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Wed Jan 31 15:45:22 2018, gautam, Update, ALS, Fiber ALS assay
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Wed Jan 31 16:29:42 2018, gautam, Update, ALS, Modulation depths 
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Wed Jan 31 16:33:53 2018, gautam, Update, ALS, ALS electronics at LSC rack
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Wed Jan 31 22:32:11 2018, gautam, Update, ALS, ALS signal chain + power budget 
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Thu Feb 1 01:24:56 2018, gautam, Update, ALS, D0902745 revamp underway
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Fri Feb 2 00:26:34 2018, gautam, Update, ALS, D0902745 revamp underway
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Fri Feb 2 13:16:55 2018, gautam, Update, ALS, ALS signals whitening switching 
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Mon Feb 5 14:11:01 2018, gautam, Update, ALS, Huge harmonics in ALS channels 
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Mon Feb 5 22:57:28 2018, gautam, Update, ALS, Huge harmonics in ALS channels
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Tue Feb 6 11:13:26 2018, gautam, Update, ALS, Possible source of ground loop identified
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Tue Feb 6 22:55:51 2018, gautam, Update, ALS, Possible source of ground loop identified
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Thu Feb 8 00:33:20 2018, gautam, Update, ALS, D990694 characterization / THD measurement plan
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Thu Feb 8 01:27:16 2018, Koji, Update, ALS, D990694 characterization / THD measurement plan
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Fri Feb 9 13:37:44 2018, gautam, Update, ALS, THD measurement trial
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Thu Feb 8 12:00:09 2018, gautam, Update, ALS, D990694 is NOT differential receiving
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Thu Feb 8 13:13:14 2018, gautam, Update, ALS, D990694 pulled out  
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Thu Feb 8 18:10:36 2018, gautam, Update, ALS, D990694 pulled out
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Wed Feb 7 15:51:15 2018, gautam, Update, ALS, D0902745 revamp complete
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Fri Feb 16 01:34:40 2018, gautam, Update, ALS, D0902745 in-situ testing 
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Tue Feb 20 23:08:27 2018, gautam, Update, ALS, D0902745 in-situ testing
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Thu Feb 22 00:09:11 2018, gautam, Update, ALS, D0902745 in-situ testing  
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Sun Feb 25 00:03:12 2018, gautam, Update, ALS, Daughter board prototyping    
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Mon Feb 26 20:55:56 2018, rana, Update, ALS, Daughter board prototyping
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Tue Feb 27 21:10:45 2018, gautam, Update, ALS, Daughter board testing  
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Wed Feb 28 19:13:25 2018, gautam, Update, ALS, ADC test for differential receiving in c1lsc
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Fri Mar 2 01:45:06 2018, gautam, Update, ALS, new look ALS electronics
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Mon Mar 5 17:27:34 2018, gautam, Update, ALS, new look ALS electronics - characterization
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Thu Mar 8 00:40:25 2018, gautam, Update, ALS, new look ALS electronics - characterization
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Thu Mar 8 19:38:37 2018, gautam, Update, ALS, digital unwhitening of daughter board
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Thu Mar 8 23:50:27 2018, gautam, Update, ALS, First look at new ALS electronics
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Fri Mar 9 01:07:01 2018, gautam, Update, ALS, First look at new ALS electronics
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Mon Mar 12 22:08:31 2018, gautam, Update, ALS, Noisy POX
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Mon Mar 12 23:57:31 2018, gautam, Update, ALS, Noisy POX 
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Mon Mar 19 15:02:29 2018, gautam, Update, ALS, Noisy MC sensing
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Thu Feb 1 15:31:12 2018, gautam, Update, ALS, ALS signal chain + power budget
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Wed Feb 7 10:16:26 2018, gautam, Update, ALS, ALS signal chain + power budget
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Thu Jan 25 13:18:41 2018, gautam, Update, ALS, Fiber ALS assay
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Message ID: 13680
Entry time: Mon Mar 12 23:57:31 2018
In reply to: 13679
Reply to this: 13688
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Author: |
gautam |
Type: |
Update |
Category: |
ALS |
Subject: |
Noisy POX |
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[kevin, gautam]
Kevin suggested I shouldn't be so lazy and test the POY spectrum as well. So we moved the timing card back to c1iscey, went through the usual dance of vertex machine reboots, and then got both single arm locks going. Attached spectrum shows that both POX and POY are noisy. I'm not sure what has changed that could cause this effect. The fact that both POX and POY appear uniformly bad, but that there is no coherence with MC_F, suggests to me that perhaps this has something to do with the work I did with Koji w.r.t. the power situation at the LSC rack. But we just checked that
- All the demod board front panel LED indicators are green.
- Marconi and all RF amplifier boxes are on (but we didn't actually measure any RF power levels yet tonight).
- We checked the KEPCO power supplies in the little cabinet along the Yarm, and all of them are reporting the correct voltages/currents as per Steve's (recently updated) labels.
- Checked the expansion chassis at the LSC rack for any red lights, there were none.
Another observation we made: note the huge bump around 70Hz in both arm control signals. We don't know what the cause of this is. But we occassionally noticed harmonics of this (i.e. 140, 210 Hz etc) appear in the control signal spectra, and they would grow with time - eventually, the X arm would lose lock (though the Y arm stayed locked).
I'm short on ideas for now so we will continue debugging tomorrow.
Unrelated to this work: Kevin reminded me that the high-pitched whine from the CRT TVs in the control room (which is apparently due to the flyback transformer) is DEAFENING. It's curious that the "chirp" to the eventual 15kHz whine is in opposite directions for the QUAD CRTs and the single display ones. Should be a Ph6 experiment maybe.
Update 2:30pm Mar 13: The furthest back I seem to be able to go in time with Frames is ~Jan 20 2018. Looking for a time when the arms were locked from back then, it seems like whatever is responsible for a noisy POX and POY was already a problem back in January. See Attachment #2. So it appears that the recent work at 1Y2 is not to blame... |
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