 Wed Jan 4 05:02:58 2012, kiwamu, Update, LSC, Sidebands measurement at POP 
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Just a quick report:
I did the first attempt
to measure the recycling gains of the sidebands in the DRMI configuration (sidebands resonant condition)
by looking at the output of the POP22/110 RFPD.
Because this time what I measured |
 Wed Jan 4 16:22:30 2012, kiwamu, Update, LSC, power normalization in LSC : modification done
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The dynamic power normalization system has been modified such that the normalization happen after the LSC input
matrix.
The attached screen shot below tells you how the signals flow.
The red circled region in the picture is the place where the power |
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Fri Jan 6 01:00:56 2012, kiwamu, Update, CDS, c1scx out of sync
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Both the c1scx and its IOP realtime processes became out of sync.
Initially I found that the c1scx didn't show any ADC signals, though the sync sign was green. |
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Mon Jan 9 13:19:09 2012, kiwamu, Update, SUS, ETMX damping restored
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No we can't do that because the c1scx model is not working properly.
If you look into the real time controller screen you will find what I mean.
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Mon Jan 9 23:52:15 2012, kiwamu, Update, CDS, SUS channels not accessible from dataviewer
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[John / Kiwamu]
We found that some of the suspensions channels (for example C1:SUS-BS_POS_IN1 and etc) were not accessible
from dataviewer for some reasons. |
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Tue Jan 10 00:09:33 2012, kiwamu, Update, LSC, spike hunting in REFL33
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[John / Kiwamu]
We tried to figure out what is causing spikes in the REFL33 signal, which is used to lock PRCL.
No useful information was obtained tonight and it is still under investigation. |
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Thu Jan 12 03:05:02 2012, kiwamu, Update, LSC, OSA installed in AS
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[John / Valera / Kiwamu]
We installed a new weapon, an optical spectrum analyzer in the AS port.
Like we used to do in the old days, two BNC cables were newly laid down and they bring the output of the OSA to the control room to monitor the |
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Tue Jan 17 01:02:07 2012, kiwamu, Update, LSC, glitch hunting in REFL RFPDs : strange
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A very strange thing is going on.
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Tue Jan 17 02:27:49 2012, kiwamu, Update, LSC, fringe tests : all the suspensions are innocent
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I did a quick test to check a hypothesis that PRM is interfering with some other optics in the single bounce configuration.
I shook all the suspensions (except the MC mirrors) at 3 Hz in POS, PIT and YAW with an amplitude of 1000 counts.
No effects were found in the REFL demod signals. |
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Tue Jan 17 02:44:59 2012, kiwamu, Update, CDS, awg not working
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AWG is not working. This needs to be fixed.
I could set the channel and the parameters in the AWGGUI screen, but it never inject signals to the realtime system. |
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Tue Jan 17 03:10:27 2012, kiwamu, Configuration, IOO, rotated lambda/2 plate
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I have slightly rotated the lambda/2 plate, which is used for attenuating the REFL beam's power on the AS table
because the plate had been at an unusual angle for investigation of the glitches since last Thursday.
It means the laser power going to the coating thermal noise setup has also changed. Just keep |
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Tue Jan 17 13:47:40 2012, kiwamu, Update, LSC, dirty steering mirror in the REFL path
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Last night I found that there were many dust particles on the second steering mirror in the REFL path on
the AS table.
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Tue Jan 17 16:09:20 2012, kiwamu, Update, CDS, awg not working on the c1sus machine
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Actually awg works fine without any problems when the excitation channels belong to the c1lsc machine.
It seems that the awg doesn't inject signals on the channels of the c1sus machine, for example C1:SUS-BS_LSC_EXC
and so on. |
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Wed Jan 18 12:36:26 2012, kiwamu, Update, LSC, wiped a steering mirror on the REFL path
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I wiped both surfaces of the REFL second steering mirror.
However no improvements. The glitches still remain. |
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Wed Jan 18 14:28:36 2012, kiwamu, Update, LSC, estimation of optical length between PRM and scattering object
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Assuming that PRM is interfering with some other optics, I have estimated the optical distance between PRM and
an object that interferes with PRM.
The optical distance is estimated to be 9.5 +/- 0.5 m. |
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Wed Jan 18 16:31:10 2012, kiwamu, Update, LSC, estimation of optical length between PRM and scattering object
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I searched for a scattering body in the REFL path.
According to the result the REFL path on the AS table is innocent.
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Thu Jan 19 23:34:52 2012, kiwamu, Update, IOO, PMC realignment and HEPA
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I realigned the incident beam to PMC at 23:30. The transmitted light went up from 0.78 to 0.83.
Also I decreased the HEPA level down to 20 % for the night time locking. |
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Fri Jan 20 15:59:02 2012, kiwamu, Update, Green Locking, Y arm ALS noige budget
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One of my goals in this week is : measurement of the current best ALS noise
budget.
Last night I took a new noise spectra of the Y arm ALS, which is shown in the attached figure below. |
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Fri Jan 20 16:24:50 2012, kiwamu, Update, Green Locking, Y arm ALS : time series
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Here is a new time series plot showing how stably ALS can control the arm length.
In the middle of the plot the cavity length was held at the resonance point for ~ 2 min. and then it passed through the resonance point to show |
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Mon Jan 23 23:12:00 2012, kiwamu, Update, IOO, PMC realignment
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I have realigned the beam pointing to PMC. The transmitted light increased from 0.74 to 0.83.
The misalignment was mainly in pitch. |
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Tue Jan 24 18:11:13 2012, kiwamu, Update, Green Locking, Y arm ALS noise budget
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I did some more stuff for the Y arm ALS and updated the noise budget:
After the works, the rms displacement improved a little bit, so it is now at 24 pm in rms. |
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Wed Jan 25 02:59:46 2012, kiwamu, Update, Green Locking, Y arm ALS noise budget
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Surprisingly increasing the gain of the whitening filter didn't improve the noise curve.
It suggests that the ADC noise is not the limiting factor below 10 Hz. |
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Thu Jan 26 05:40:10 2012, kiwamu, Update, LSC, glitch in the analog demodulated signals
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Indeed the glitches show up in the analog demodulated signals. So it is not an issue of the digital processing.
With an oscilloscope I looked at the I/Q monitor outputs of the LSC demodulators, including REFL11, REFL33, REFL55, POY11, AS55 while keep locking |
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Thu Jan 26 06:09:52 2012, kiwamu, Update, Green Locking, noisy AS55
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During the Y arm ALS I found that the noise of the AS55 demod signal was worse than that of POY11 in terms of
the Y arm displacement.
There is a bump from 500 mHz to 100 Hz in the AS55 signal while POY11 didn't show such a structure in |
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Thu Jan 26 19:28:02 2012, kiwamu, Update, IOO, PMC low transmission
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After I recovered the lock of PMC, I found that the PMC transmission was quite low. It was about 0.26 in the EPICS display.
I zeroed the PSL temperature feedback value which had been -2.3 and then the PMC transmission went back to a normal value of 0.83.
I believe it was because the PSL was running with two different oscillation modes due to the big temperature offset. |
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Fri Jan 27 05:21:43 2012, kiwamu, Update, Green Locking, fine alignment of the Y end green setup
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I did a fine alignment on the Y end green setup. The green light became able to be locked again.
Quote from #6227
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Fri Jan 27 06:07:47 2012, kiwamu, Update, LSC, glitch hunting
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I went through various IFO configurations to see if there are glitches or not.
Here is a summary table of the glitch investigation tonight. Some of the cells in the table are still not yet checked
and they are just left blank. |
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Fri Jan 27 17:16:05 2012, kiwamu, Update, LSC, hypothetical glitch scenario
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Here is a hypothetical scenario which could make the glitches in the LSC error signals. It can be considered as a 4 step phenomenon.
(1) up conversion noise due to a large motion at 3 Hz
=> (2) rms level exceeds the line width (a.k.a. linear range) in some LSC sensors |
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Mon Jan 30 23:10:02 2012, kiwamu, Update, SUS, drift mon script needs to be fixed
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[Rana / Kiwamu]
We tried to set some parameters for the suspension drift monitor but the old matlab script, which automatically sets the values, didn't run because
it uses the old mDV protocol. |
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Tue Jan 31 14:58:30 2012, kiwamu, Update, IOO, laser shuts down
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[Steve/ Kiwamu]
We found that the laser had completely shut off for ~ 4 hours even with all the PSL doors closed.
We are guessing it is related to the interlock system and Steve is working on it to fix it. |
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Fri Feb 10 02:35:29 2012, kiwamu, Update, IOO, crazy ground motion
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I gave up tonight's locking activity because the MC can't stay locked.
It seems that somehow the seismic noise became louder from about 1:00 AM. |
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Fri Feb 10 23:19:09 2012, kiwamu, Update, IOO, cross talk causing fake seimometer signals
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[ Koji / Kiwamu ]
The frequent unlock of the MC are most likely unrelated to ground
motion. |
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Wed Feb 15 05:29:22 2012, kiwamu, Update, LSC, sensing matrix of PRMI
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I have measured the sensing matrix of PRMI.
It seems that the MICH signal in the 3f ports (REFL33 and REFL165) were quite tiny, and because of that
it is very tough to use them for the actual MICH control. |
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Wed Feb 15 17:15:33 2012, kiwamu, Update, LSC, sensing matrix of PRMI
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I think I have told a lie in the last meeting -- the measured sensing matrix doesn't look similar to what Optickle
predicts.
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Thu Feb 16 03:47:16 2012, kiwamu, Update, LSC, glitch table
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I updated the table which I posted some time ago (#6231). The latest table is shown below.
It seems that the glitches show up only when multiple DOFs are locked.
Interesting thing is that when the low finesse PRMI is locked with a big MICH offset (corresponding to |
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Thu Feb 16 04:02:16 2012, kiwamu, Update, LSC, insane REFL165 DC output
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I found that the DC monitor of the REFL165 was showing 9 V regardless of how much laser power goes to the diode.
I am worried about whether the RF output is also broken. |
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Thu Feb 16 04:29:30 2012, kiwamu, Update, LSC, upconversion noise from BS motion
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Sometimes ago I reported that there have been a kind of upconversion noise when PRM was excited (#6211).
This time I found another one, which showed up when BS was excited.
Assuming this is related to some kind of scattering process and also assuming this is from the same scattering |
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Thu Feb 16 23:12:55 2012, kiwamu, Update, IOO, MC unlocking frequently
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The MC became crazy again.
It seems that there were corresponding steps in the OSEM signals. Look at the one-day trend posted below.
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Fri Feb 17 01:02:22 2012, kiwamu, Update, IOO, MC is back to normal
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[Koji / Kiwamu]
The MC is now back to normal. The beam pointing to the interferometer is good.
There were two different issues : |
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Fri Feb 17 04:45:48 2012, kiwamu, Update, LSC, sensing matrix of PRMI
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I locked the PRMI with the AS55I and Q combination.
It seems the glitche rate decreased,
but I am not 100 % sure because the rest of the demod signals (i.e. REFL11 and etc) were showing relatively big signals (noise ?), which may cover |
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Sat Feb 18 16:58:59 2012, kiwamu, Update, IOO, MC suspension realigned
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[ Den / Kiwamu]
We have realigned the MC suspensions so that the WFS servos are smoothly engaged.
Now it seems working fine. The beam pointing to the interferometer also looks okay. |
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Tue Feb 21 04:30:02 2012, kiwamu, Update, LSC, Y arm + PRMI
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I tried the "Yarm + PRMI" configuration to see what happens.
The Y arm was locked at a resonance and held with the ALS technique.
On the other hand, the X arm was freely swinging. |
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Tue Feb 21 16:10:29 2012, kiwamu, Update, IOO, degradation in input PZT1
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PZT1, the one with Koji's custom mid-HV driver (#5447), is getting degraded.
The movable range in the pitch direction became narrower than what it used to be (maybe a factor of 3 estimated |
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Tue Feb 21 18:39:11 2012, kiwamu, Update, Green Locking, New BBPDs installed
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Two new BBPDs have been installed on the PSL table.
The first one was installed by Koji a few days ago, and I stalled the second one today.
They will serve as beat-note detectors for the green locking. |
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Wed Feb 22 01:53:57 2012, kiwamu, Update, LSC, update on glitch table
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I tried SRMI. The glitch rate wasn't as high as that of PRMI but it happened once per 10 sec or so.
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Wed Feb 22 13:28:22 2012, kiwamu, Update, LSC, Y arm + central part locking
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Last night I tried the "Y arm + central part" locking again. Three different configuration
were investigated :
Y arm + DRMI
Y arm + PRMI
Y arm + MICH
In all the configurations I displaced |
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Wed Feb 22 19:45:33 2012, kiwamu, Update, LSC, how much length offset do we need ?
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I did a quick calculation to see if the offset of the arm length which I tried last night was reasonable or not.
The conclusion is that the 20 nm offset that i tried could be a bit too close to a resonance of the 55 MHz sidebands. |
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Fri Feb 24 03:58:13 2012, kiwamu, Update, LSC, Y arm + PRMI part II
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I tried the Yarm + PRMI configuration again.
The PRMI part was locked, but it didn't stay locked during the Y arm was brought to the resonance point.
I will post the time series data later. |
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Fri Feb 24 04:12:44 2012, kiwamu, Update, SUS, freeswing test
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The following optics were kicked:
MC1 MC2 MC3 ETMX ETMY ITMX ITMY PRM SRM BS
Fri Feb 24 04:11:15 PST 2012
1014120690
Steve (or anyone), can you restore the watchdogs when you come to the lab in the morning ?
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Fri Feb 24 15:01:31 2012, kiwamu, Update, LSC, Y arm + PRMI part II
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The figure below shows the time series of the Y arm + PRMI trail.
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