 Mon Aug 11 23:32:54 2014, ericq, Summary, IOO, MC demod measurement 
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Here's the magnitude plot of the board TF. As mentioned above, this was done with Marconi+Scope, so we were not able to get the phase of this transfer
function.
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 Thu Aug 14 22:58:59 2014, rana, jenne, Summary, Green Locking, ALS DIFF tuning
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We've been having trouble tuning the ALS DIFF matrix. Trying to see if the MC2 EXC can be cancelled in ALS DARM by adjusting the relative gains
in ALSX and ALSY Phase Tracker outputs.
There's a bunch of intermittent behavior. Between different ALS locks, we get more or less cancellation. We were checking this by driving MC2 at |
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Thu Aug 14 23:19:49 2014, rana, Summary, LSC, ETM Violin fundamental filters moved to LSC
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We used to do violin mode and test mass body mode notches in the SUS-LSC filter modules. Now we want them balanced in the LSC and triggered by
the LSC, so they're in the filter modules which go from the the LSC output matrix to the SUS.
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Mon Aug 18 09:42:50 2014, Koji, Summary, IOO, MCREFL PD charcterization
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Riju did the measurement of the MCREFL PD.
I found data files in her directory on the control machine.
I was not sure how much was the transimpedance of the DC out. |
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Thu Aug 21 22:10:52 2014, rana, Summary, Computer Scripts / Programs, network movements
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To help development of the data visualization project, we've assigned the .101 and .102 IP to DataVis. This is being used by the iMac in the control
room via port 8 of the CDS switch near the Blue Plataeu Tournant.
We tried using one of the free ports, but Jamie realized that we had to use one of the already assigned ones due to some 'Smart' switch management |
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Fri Aug 22 15:11:55 2014, andres, nicolas, Summary, IOO, MC WFS activity
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1. Before doing anything, we centered the IOO QPDs.
2. With the WFS enabled, we offloaded the control signals onto the bias sliders. Then we saved the slider values. The MC LSC diode had a DC value
of ~0.5 |
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Fri Aug 22 15:58:02 2014, Steve, Summary, IOO, MC WFS activity
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Tue Sep 2 22:54:27 2014, Koji, Summary, LSC, phase tracker UGF
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FYI and FMI
Phase tracker UGF is Q_AMP * G * 2 PI / 360 where Q_AMP is the amplitude of the Q_ERR output and G is the gain of the phase tracker.
For example: Q_AMP = 270, G = 4000\ => UGF = 1.9kHz |
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Thu Sep 4 18:30:13 2014, Gabriele, Summary, ASC, Optimal Gouy phase for POP QPD
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Jenne asked me to simulate the signals on POP QPD when moving different mirrors, as a function of the Gouy phase where the QPD is placed.
I used the opportunity to create a MIST simulation file of the entire 40m interferometer, essentially based on my aLIGO configuration file. I used
the recycling cavity lengths obtained from our survey, and other parameters from the wiki |
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Fri Sep 5 00:56:00 2014, rana, Summary, Optical Levers, ITM OLs recentered: violations found
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I re-centered the ITMX & ITMY Optical lever beams today since they were off. First I aligned the beam into the vacuum so that it went through the
center of the on table optics and then tweaked the receiver optics alignment.
There are several bad practices on these which probably makes them drift: |
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Wed Sep 10 22:17:29 2014, Koji, Summary, LSC, X/Y green beat mode overlap measurement
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[Koji Manasa]
We made quantitative inspection of the X/Y green beat setup on the PSL table.
DC output of the BBPD for each arm was measured by blockiing the beams at either or both side of the recombination BS. |
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Thu Sep 18 10:08:07 2014, steve, Summary, SUS, oplev laser summary updated
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Quote:
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Mon Nov 10 23:14:20 2014, rana, Summary, SUS, SRM: damping gains & Optical Lever servo Tune-up
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tweaked gains for POS, PIT, YAW, SIDE by ~10-20% to get nice ringdowns with Q~5.
Measured bounce rool freqs = 16.43 /
23.99 Hz. Updated the Mech Res Wiki page. Tightened up the bandstops to get back a few deg of phase. Propagated these new bandstops into the SRM SUS damping
filter banks.
Made and turned on a LP filters for the loops.
Added a ~0.3 Hz gain boost / bubble.
Set UGF to |
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Wed Nov 12 22:22:11 2014, Koji, Summary, IOO, Estimation of the angular jitter imposed by the TTs
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[Koji, Rana, Jenne]
One coil of the TT produce 36nrad/rtHz at DC.
- C1:IOO-TT2_UL_EXC was excited with 5 count_pk at 0.04Hz. |
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Mon Nov 17 20:28:17 2014, rana, Summary, IOO, MC servo summing amp
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I modified the /cvs/cds/caltech/target/c1psl/psl.db file to adjust the records for the FSS-FAST signal (to make it go yellow / red at the correct
voltages). This was needed to match 5V offset which Koji added to the output of the FSS board back in August.
I also manually adjusted the alarm levels with caput so that we don't have to reboot c1psl. Beware of potential tiimebomb / boot issues if I made |
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Sun Dec 7 13:11:57 2014, manasa, Summary, General, Frequency Offset Locking - To Do List
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| Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours. |
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Mon Dec 8 15:54:39 2014, manasa, Summary, General, Dec 8 - Check Frequency Counter module
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Quote:
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon |
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Mon Dec 8 20:53:51 2014, diego, Summary, General, Dec 8 - Check Frequency Counter module
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Quote:
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Tue Dec 9 00:30:27 2014, manasa, Summary, General, Dec 9 - Elaborate to do list
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Quote:
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon |
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Tue Dec 9 16:06:46 2014, diego, Summary, General, Dec 8 - Check Frequency Counter module
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Quote:
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Tue Dec 9 16:07:16 2014, manasa, Summary, General, Dec 9 - FC module and fiber chassis
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Quote:
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Wed Dec 10 16:12:29 2014, manasa, Summary, General, Dec 10 - PSL table
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Quote:
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon |
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Thu Dec 11 12:50:12 2014, manasa, Summary, General, PSL table optical layout
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I assembled the telescope to couple PSL light into the fiber. The maximum coupling that I could obtain was 10mW out of 65mW (~15%).
I was expecting to achieve 80-90% coupling from my design estimates. It makes me wonder if the beam waist measurements made by Harry during summer |
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Thu Dec 11 23:34:06 2014, manasa, Summary, General, PSL table optical layout
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Quote:
I assembled the telescope to couple PSL light into the fiber. The maximum coupling that I could obtain was |
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Fri Dec 12 02:30:25 2014, Jenne, Summary, General, PSL table optical layout
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Quote:
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Fri Dec 12 14:38:39 2014, manasa, Summary, General, Frequency Offset Locking - To Do List (Revised)
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Unfortunately the order placed for beam samplers last week did not go through. These will be used at the X and Y end tables to dump the unwanted light
appropriately. Since they will not be here until Tuesday, I revised the timeline for FOL related activities accordingly. |
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Fri Dec 12 15:19:04 2014, manasa, Summary, General, Dec 12 - PSL table
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Quote:
Unfortunately the order placed for beam samplers last week did not go through. These will be used at the X and Y end tables to dump the unwanted |
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Mon Dec 15 22:40:09 2014, rana, Summary, PSL, PMC restored
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Found that the PMC gain has been set to 5.3 dB instead of 10 dB since 9 AM this morning, with no elog entry.
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Wed Dec 17 11:57:56 2014, manasa, Summary, General, Y arm optical layout
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I was working around the PSL table and Y endtable today.
I modified the Y arm optical layout that couples
the 1064nm light leaking from the SHG crystal into the fiber for frequency offset locking. |
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Mon Dec 22 15:46:58 2014, Kurosawa, Summary, IOO, Seven transfer functions
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| IMC OL TF has been measured from 10K to 10M |
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Tue Dec 30 20:35:59 2014, rana, Summary, PSL, PMC Tune Up
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Calibrated the Phase Adjust slider for the PMC RF Modulation; did this by putting the LO and RF Mod out on the TDS 3034 oscope and triggering
on the LO. This scope has a differential phase measurement feature for periodic signals.
Calibrated the RF Amp Adj slider for the PMC RF
Modulation (on the phase shifter screen)
The PMC 35.5 MHz Frequency reference card is now in our 40m DCC Tree.
The LO |
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Thu Jan 8 19:02:42 2015, Jax, Summary, Electronics, MC demod modifications
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Here's a summary of the changes made to the D990511 serial 115 (formerly known as REFL 33), as well as a short procedure. It needed tuning to
29.5MHz and also had some other issues that we found along the way.
So here's a picture of it as built: |
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Wed Jan 14 02:11:07 2015, rana, Summary, Treasure, 2-loop Algebra Loopology
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I show here the matrix formalism to calculate analytically the loop TF relationships for the IMC w/ both FSS actuators so
that it would be easier to interperet the results.
The attached PDF shows the Mathematica notebook and the associated block diagram.
In the notebook, I have written the single hop connection gains into the K matrix. P is the optical plant, C is the Common electronic gain, F |
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Wed Jan 28 23:53:24 2015, Koji, Summary, ASC, Xarm ASS fix
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X-Arm ASS was fixed.
ASS_DITHER_ON.snap was updated so that the new setting can be loaded from the ASS screen.
The input and output matrices and the servo gains were adjusted as found in the attached image. |
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Wed Feb 4 18:27:55 2015, Koji, Summary, ASC, Xarm ASS fix
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Please remember that Xarm ASS needs FM6 (Bounce filters) to be ON in order
to work properly. |
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Sat Feb 7 13:34:11 2015, Koji, Summary, PSL, ISS AOM driver check
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I wanted to check the status of the ISS. The AOM driver response was measured on Friday night.
The beam path has not been disturbed yet.
- I found the AOM crystal was removed from the beam path. It was left so. |
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Sun Feb 8 21:54:50 2015, rana, Summary, PSL, ISS AOM driver check
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This is good news. It means that the driver probably won't limit the response of the loop - I expect we'll get 20-30
deg of phase lag @ 100 kHz just because of the acoustic response of the AOM PZT + crystal. |
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Wed Feb 11 18:11:46 2015, Koji, Summary, LSC, 3f modulation cancellation
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33MHz sidebands can be elliminated by careful choice of the modulation depths and the relative phase between the modulation signals.
If this condition is realized, the REFL33 signals will have even more immunity to the arm cavity signals because the carrier signal will lose
its counterpart to produce the signal at 33MHz. |
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Sat Feb 14 19:54:04 2015, Koji, Summary, LSC, 3f modulation cancellation
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Optical Setup
[Attachment 1]
Right before the PSL beam goes into the vacuum chamber, it goes through an AR-wedged plate. |
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Sat Feb 14 20:37:51 2015, Koji, Summary, LSC, 3f modulation cancellation
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Experimental results
- PD response [Attachment 1]
The AUX laser temperature was swept along with the note by Annalisa [http://nodus.ligo.caltech.edu:8080/40m/8369] |
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Sat Feb 14 22:14:02 2015, Koji, Summary, LSC, [HOW TO] 3f modulation cancellation
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When I finished my measurements, the modulation setup was reverted to the conventional one.
If someone wants to use the 3f cancellation setting, it can be done along with this HOW-TO.
The 3f cancellation can be realized by adding a carefully adjusted delay line and attenuation for the 55MHz modulation |
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Sun Feb 15 16:20:44 2015, Koji, Summary, LSC, [ELOG LIST] 3f modulation cancellation
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Summary of the ELOGS
3f modulation cancellation theory
http://nodus.ligo.caltech.edu:8080/40m/11005
3f modulation cancellation adjustment setup http://nodus.ligo.caltech.edu:8080/40m/11029 |
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Sun Feb 15 20:55:48 2015, rana, Summary, LSC, [ELOG LIST] 3f modulation cancellation
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I wonder if DRMI can be locked on 3f using this lower 55 MHz modulation depth. It seems that PRMI should be unaffected, but that the 3*f2 signals for
SRCL will be too puny. Is it really possible to scale up the overall
modulation depths by 3x to compensate for this? |
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Mon Feb 16 00:08:44 2015, Koji, Summary, LSC, [ELOG LIST] 3f modulation cancellation
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This KTP crystal has the maximum allowed RF power of 10W (=32Vpk) and V_pi = 230V. This corresponds to the maximum allowed
modulation depth of 32*Pi/230 = 0.44. So we probably can achieve gamma_1 of ~0.4 and gamma_2 of ~0.13. That's not x3 but x2,
so sounds not too bad. |
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Mon Feb 16 01:45:12 2015, Koji, Summary, LSC, modulation depth analysis
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Based on the measured modulation profiles, the depth of each modulation was estimated.
Least square sum minimization of the relative error was used for the cost function.
-8th, -12th~-14th, n=>7th are not included in the estimation for the nominal case. |
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Fri Mar 6 00:59:13 2015, rana, Summary, IOO, MC alignment not drifting; PSL beam is drifting
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In the attached plot you can see that the MC REFL fluctuations started getting larger on Feb 24 just after midnight. Its been bad ever since. What happened that night or the afternoon of Feb 23?
The WFS DC spot positions were far off (~0.9), so I unlocked the IMC and |
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Fri Mar 6 13:48:17 2015, dark kiwamu, Summary, IOO, triple resonance circuit
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I was asked by Koji to point out where a schematic of the triple resonant circuit
is.
It seems that I had posted a schematic of what currently is installed (see elog 4562 from |
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Fri Mar 6 19:54:15 2015, rana, Summary, IOO, MC alignment not drifting; PSL beam is drifting
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MC Refl alignment follow up: the alignment from last
night seems still good today. We should keep an on the MC WFS DC spots and not let them get beyond 0.5. |
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Wed Mar 11 19:15:03 2015, Koji, Summary, LSC, ROUGH calibration of the darm spectrum during the full PRFPMI lock
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I made very rough calibration of the DARM spectra before and after the transition for the second lock on Mar 8.
The cavity pole (expected to be 4.3kHz) was not compensated. Also the servo bump was not compensated.
[Error calibration] |
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Thu Mar 19 16:58:19 2015, Steve, Summary, IOO, MC alignment not drifting; PSL beam is drifting
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Polaris mounts ordered.
Quote:
In the attached plot |