 Wed Jul 21 19:11:18 2010, Dmass, Update, Green Locking, locked
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What did you use to filter the 2f components from your error signal? A homemade low pass or what?
Kiwamu: |
 Mon Jul 9 05:15:46 2012, yuta, Update, Green Locking, locked MI while ALS using ASDC 
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I locked MI while both arm length are stabilized at IR resonance. This could be done using DC READOUT, in
other words, use AS_DC as MICH error signal.
Lock using RF signals are still not successful. |
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Wed Jan 12 01:39:49 2011, kiwamu, Update, LSC, locked X arm
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[Suresh, Kiwamu]
We eventually succeeded
in locking X arm with the infrared beam. |
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Fri Dec 3 05:21:11 2010, kiwamu, Update, Green Locking, locked the laser to the cavity
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I succeeded in locking the end green laser to X arm with the new ETM.
Though the lock is still not so stable compared to the previous locking with the old ETM. Also the beam centering |
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Thu May 2 00:34:57 2013, Koji, Update, LSC, locking
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- Routine alignment
Locked the arm cavties. Ran ASS. As this was not enough precise alignment for PRMI locking, Yarm alignment was re-adjusted by sliders.
Xarm was also aligned in the same way. |
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Wed Jan 29 00:29:43 2020, gautam, Update, LSC, locking 2020
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The goal tonight was to go through the locking scripts to see if I could recover the state from November 2019, when I could have the arm lengths controlled
by ALS, and sit at zero CARM offset with the PRMI remaining locked and the arm powers fluctuating between 0-300. The IR-->ALS transitions went smoothly
tonight, and the PRMI locking was also fairly robust when the CARM offset was large, but was less good when reduced to 0. Nevertheless, it is good to know |
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Thu Dec 12 00:47:45 2013, Den, Update, LSC, locking activity
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Jenne, Den
Today we worked on PRM angular servos and Y-arm ALS stabilization.
In the current PRMI angular control configuration two servos simultaneously drive PRM - oplev and POP ASC. We considered 2 ways to redesign this |
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Fri Dec 13 02:19:57 2013, Jenne, Update, LSC, locking activity
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[Jenne, Den]
Tonight we worked on tweaking up the PRCL new ASC, and then PRMI+1 arm locking. We were unable to get the Xarm to stay locked on a
TEM00 mode for very long, and after an hour or two of using the PZTs to try to align the beam to the cavity, we gave up and just used Yarm green. |
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Fri Dec 13 02:30:22 2013, Koji, Update, LSC, locking activity
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According to the measurement by Eric, the X-arm green PDH UGF is too low. We still have some room to increase the gain.
The out of loop stability of the ALS for each arm should be measured everyday.
Otherwise we can't tell whether the arm is prepared for advanced locking activities or not. |
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Sat Dec 14 02:51:47 2013, Den, Update, LSC, locking activity
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I had a look on x,y arms stabilization using ALS. Input green beam was misaligned and I was loosing 00 every few minutes. I vent on the floor and realigned
green beams.
YARM alignemt was smooth - transmission increased from 0.4 to 0.85 with PSL shutter off. |
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Tue Dec 17 02:10:29 2013, Den, Update, LSC, locking activity
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Koji, Den
Some results and conclusions from tonight:
PRC macroscopic length is detuned. We measured REFL phases in carrier and sideband configurations - they are different by ~45 degrees for both |
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Fri Apr 25 03:14:46 2014, ericq, Update, LSC, locking activity
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[ericq, Jenne, Zach]
We spent some time tonight trying to push our CARM locking further, to little avail. DARM/CARM loop oscillations kept sneaking up on us. We measured
some MC2 motion -> REFL11 Transfer Functions to see if we could see CARM plant features; plots will come in the near future... |
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Fri Apr 25 13:18:08 2014, Dark Jamie, Update, LSC, locking activity
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Quote:
[ericq, Jenne, Zach] |
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Fri Oct 28 05:17:13 2011, kiwamu, Update, LSC, locking activity : PZT1 is still railing
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Status update on the LSC activity:
To see how good/bad the beam pointing is, I locked the Y arm with POY11. |
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Tue Sep 20 03:02:23 2011, Keiko, Update, LSC, locking activity tonight
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Keiko, Anamaria, Koji
We were not able to establish the stable DRMI tonight. We could lock MICH and PRCL quite OK, and lock the
three degrees of freedom at somewhere strange for several seconds quite easily, but the proper DRMI lock was not obtained.
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Wed Dec 7 02:55:38 2011, kiwamu, Update, Green Locking, locking activity tonight
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No real progress.
Probably I spent a bit too much time realigning the beat-note optical path.
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Wed Jan 4 03:03:24 2012, kiwamu, Update, LSC, locking activity tonight and beyond
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Last night and tonight, I was doing a kind of rehabilitation -- locking PRMI and DRMI with the new trigger system.
Although MC wasn't so awesome (#6164), I confirmed that the DRMI can stay locked with the conventional RFPD combination ( |
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Sun Apr 20 18:23:27 2008, rana, Summary, LSC, locking attempts
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I noticed that the adaptive FF for the MC had stopped doing anything; this turned out
to be that the MC lost lock and the mcdown script turned off the FF path to MC1.
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Tue Aug 18 03:56:09 2015, ericq, Update, LSC, locking efforts
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Now that the updated ALS is stable, and the PRC angular FF is revived, I've been working on relocking PRFPMI. While the RMS arm fluctuations are
surely smaller than they used to be, there is no noticible difference to the ears when buzzing around resonance, but this doesn't really mean much.
Frustratingly, I am not able to stably blend in any RF CARM error signal into the slow length control path (i.e. CARM_B). Bringing AS55 |
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Wed May 4 13:45:56 2011, kiwamu, Update, LSC, locking last night
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Last night I was trying to calibrate the MICH error signal and the actuators on BS and ITMs.
However I gave up taking the data because the MC locking was unstable. MC3 drifted a lot. |
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Fri Mar 30 10:20:51 2012, kiwamu, Update, LSC, locking last night
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I was trying to make the DRMI lock more robust.
Increasing the gains of the oplev on SRM helped a lot, but the lock is still not solid enough for measurements.
According to some line injection tests, the SRCL and MICH signals show up in AS55Q with almost the same amplitudes. |
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Fri Nov 22 00:54:14 2019, gautam, Update, LSC, locking notes
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[KA, GV]
There was no shaking (that disturbed the locking) tonight!
REFL165 Demod phase was adjusted from -111deg to -125deg. To minimize coherence b/w MICH and PRCL.
MICH 3f loop gain changed |
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Fri May 20 03:01:17 2011, kiwamu, Update, LSC, locking status
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(PRMI locking)
Since REFL11 has gone I tried locking the PRMI with combination of REFL55 and AS55.
Without any pain the lock of PRMI was achieved successfully. |
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Wed Jul 27 01:58:23 2011, kiwamu, Update, LSC, locking status
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Through some locking exercise I found
that several things are degrading.
Remember the interferometer |
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Wed Jul 27 08:59:10 2011, Suresh, Update, LSC, locking status
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I had to realign PSL beam into the MC in order to reobtain the MC lock. We lost lock at sometime around 8:30 AM on Tuesday. See attached
trend data for MC_RFPD_DCMON.
The is the second time this week that I had to do this when we were unable to obtain the MC lock. On both occassions the zig-zag at the end |
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Wed Jul 27 10:10:12 2011, steve, Update, PSL, locking status
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| 80 days: PMC is drifting |
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Fri Oct 14 04:35:45 2011, kiwamu, Update, LSC, locking tonight
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| The lock of DRMI wasn't stable enough to measure the sensing matrix. Failed. |
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Thu Apr 24 14:10:26 2008, rob, Update, Locking, locking work
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[I]Rob, Johnnie[/I]
We made some progress on locking last night (Wed night), namely that we were able to handoff (briefly) the CARM-MCL path the REFL-DC error signal. We |
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Sun Oct 24 19:55:50 2010, kiwamu, Update, Electronics, lonely RF amplifier on ITMX table
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(Rana, Kiwamu)
Last Friday we found a lonely RF amplifier ZHL-3A on the ITMX table.
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Tue Aug 9 13:53:57 2016, babbott, Update, SEI, long Guralp EX cable repaired on the D-sub side
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I checked out the cable that I took from you, and all of the connections looked right. The only
thing I did notice was that some of the soldered wires on the 37-pin connector had gotten hot enough to melt their insulation, and potentially short together.
I cut off that connector, and left it on your desk to check out. I put on a new connector, and checked the pinout. If the Guralps still doesn't |
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Wed Jul 16 17:51:58 2008, Masha, Update, Auxiliary locking, long measurement
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I'm taking a measurement on the SR785 spectrum analyzer at low frequencies, so I'm going to leave it by the symmetric port table for a while. Please don't
move it! |
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Wed Jul 16 22:29:05 2008, Masha, Update, Auxiliary locking, long measurement
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[quote]I'm taking a measurement on the SR785 spectrum analyzer at low frequencies, so I'm going to leave it by the symmetric port table for a while. Please
don't move it![/quote]
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Mon Nov 23 10:11:03 2009, steve, Update, PEM, long term temp fluctuation of the 40m lab
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Quote:
This first plot shows the RC temperature channels' performance from 40 days ago, before we disabled the MINCO PID |
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Thu Jun 9 18:25:22 2011, kiwamu, HowTo, CDS, look back a channel which doesn' exist any more
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For some purposes I looked back the data of some channels which don't exist any more. Here I explain how to do it.
If this method is not listed on the wiki, I will put this instruction on a wiki page. |
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Thu May 2 19:59:34 2013, Jamie, Update, Computer Scripts / Programs, lookback: new program to look at recent past testpoint data
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To aid in lock-loss studies, I made a new program called 'lookback', similar to 'getdata', to look at past data.
When called with channel name arguments, it runs continuously, storing all channel data in a ring buffer. When the user hits Ctrl-C, all
the data in the ring buffer is displayed. There is an option to store the data in the ring buffer to disk as well. |
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Wed May 11 17:20:24 2011, kiwamu, Configuration, IOO, loop diabled on PZT2
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[Valera / Kiwamu]
The pointing of the incident beam to the interferometer
has been jumping frequently. |
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Fri Oct 16 16:08:00 2009, rob, Configuration, ASC, loop opened on PZT2 YAW at 3:40 pm
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I pushed the "closed loop" button on PZT2 YAW around 3:40 pm today, then roughly recentered it using the DC Offset knob on the PiezoJena controller
and the IP ANG QPD readbacks. There was a large DC shift. We'll watch and see how much it drifts in this state. |
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Fri Oct 16 18:46:36 2009, rana, Configuration, ASC, loop opened on PZT2 YAW at 3:40 pm
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Quote:
I pushed the "closed loop" button on PZT2 YAW around 3:40 pm today, then roughly recentered it using the |
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Sun Oct 18 16:09:34 2009, rana, Configuration, ASC, loop opened on PZT2 YAW at 3:40 pm
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I wanted to see how long our IP POS beam has been badly clipped - turns out its since April 1, 2007.
Steve's |
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Fri May 20 01:02:50 2011, loose connection hunter, Update, SUS, loose connection on ETMY rack
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The UL signal of the shadow sensor on ETMY went to zero this evening.
This was due to a loose connection on the cross connection board on the 1Y4 rack.
In order to make them tighten, a combination of stand-offs and screws were installed on the connectors. |
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Mon Nov 12 13:53:20 2018, rana, Update, IOO, loss measurement: oscope vs CDS DAQ
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sstop using the ssscope, and just put the ssssignal into the DAQ with sssssome whitening. You'll get 16 bitsśšß.
Quote:
I increased the resolution on the scope by selecting Average (512) mode. I was a bit confused by this, since Yuki |
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Wed Oct 31 08:34:35 2007, rana, Other, IOO, loss measurements
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In the end, we were unable to get a good scatter measurement just because we ran out of steam. The idea was to get a frame
grab image of MC2 but that involves getting an unsaturated image.
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Thu Oct 11 13:40:51 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Quote:
This is the procedure I follow when I take these measurements for the XARM (symmetric under XARM <-> YARM):
Dither-align the interferometer with both arms locked. Freeze outputs when done.
Misalign ETMY + ITMY.
ITMY |
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Fri Oct 12 12:29:34 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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With Gautam's help, Y-arm was locked. Then I ran the script "armloss_dcrefl_asdcpd_scope.py" which gets the signals from oscilloscope.
It ran and got data, but I found some problems.
It seemed that a process which makes arm cavity mislaigned in the script didn't work.
The script "armloss_dcrefl_asdcpd_scope.py" |
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Fri Oct 12 20:20:29 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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I ran the script for measuring arm-loss and calculated rough Y-arm round trip loss temporally. The result was 89.6ppm. (The error should be considered
later.)
The measurement was done as follows: |
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Sat Oct 13 20:11:10 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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Quote:
the script "armloss_AS_calc.py",
"ETM_YAW_L_DEMOD_I_OUTPUT" was little noisy even when the arm was locked.
The reflected beam power when |
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Mon Oct 15 10:32:13 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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I used these values for measuring armloss:
Transmissivitity of ITM = 1.384e-2 * (1 +/- 1e-2)
Transmissivitity of ETM = 13.7e-6 * (1 +/- 5e-2)
Mode-Matching
efficiency of XARM = 0.912 * (1 +/- 2e-2)
Mode-Matching efficiency of YARM = 0.867 * (1 +/- 2e-2)
modulation depth m1 (11MHz) = 0.179 |
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Tue Oct 16 00:44:29 2018, yuki, Update, Computer Scripts / Programs, loss measurements
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The scripts for measuring armloss are in the directory "/opt/rtcds/caltech/c1/scripts/lossmap_scripts/armloss_scope".
armloss_derefl_asdcpd_scope.py: gets data and makes ascii file.
armloss_AS_calc.py: calculates armloss from selected a set
of files.
armloss_calc_histogram.py: calculates armloss from selected files and makes histogram.
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Fri Nov 2 19:25:16 2018, gautam, Update, Computer Scripts / Programs, 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 |
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Wed Mar 8 18:18:51 2017, johannes, Update, Computer Scripts / Programs, loss script
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I started a loss script on Donatella that will scan the beam spot across ETMY, recording the reflected power from the arm via the networked scope at
the AS port until later tonight (should be done by 9 pm). ITMX is currently strongly misaligned for this, but can be restored with the saved values. I
mostly adapted the mapping scipts for the scope readout but still have to iron out a few kinks, which is why I'm running this test. In particular, |