40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
 40m Log, Page 164 of 344 Not logged in
ID Date Author Type Category Subject
13500   Wed Jan 3 16:25:32 2018 awadeUpdateOptimal ControlOplev loop tuning

Another cool feature is client side pre-commit hooks. They can be used to run checks on the local version at the time of commit and refuses to push until the pass/fail exits 0.

Can be the same as the Gitlab CI or just basic code quality checks.  I use them to prevent jupyter notebooks being commited with uncleared cells. It needs to be set up on the user's computer manually and is not automatically cloned with the directory: a script can be included in the repo to do this and run manually on first time clone.

 Quote: When putting code into git.ligo.org, one way to have automated testing is to use the Gitlab CI. This is an automated 'checker', much like the 'Travis' system used in GitHub. Essentially, you give it a make files which it runs somewhere and your GIT repo web page gets a little 'failed/passing' badge telling you if its working. You can also browse the logs to see in detail what happened. This avoids the 'but it works on my computer!' thing that we usually hear.

13520   Tue Jan 9 21:57:29 2018 gautamUpdateOptimal ControlOplev loop tuning

After some more tweaking, I feel like I may be getting closer to a cost-function definition that works.

• The main change I made was to effectively separate the BR-bandstop filter poles/zeros and the rest of the poles and zeros.
• So now the input vector is still a list of highest pole frequency followed by frequency separations, but I can specify much tighter frequency bounds for the roots of the part of the transfer function corresponding to the Bounce/Roll bandstops.
• This in turn considerably reduces the swarming area - at the moment, half of the roots are for the notches, and in the (f0,Q) basis, I see no reason for the bounds on f0 to be wider than [10,30]Hz.

Some things to figure out:

1. How the "force" the loop to be AC coupled without explicitly requiring it to be so? What should the AC coupling frequency be? From the (admittedly cursory) sensing noise measurement, it would seem that the Oplev error signal is above sensing noise even at frequencies as low as 10mHz.
2. In general, the loops seem to do well in reducing sensing noise injection - but they seem to do this at the expense of the loop gain at ~1Hz, which is not what we want.
• I am going to try and run the optimizer with an excess of poles relative to zeros
• Currently, n(Poles) = n(Zeros), and this is the condition required for elliptic low pass filters, which achieve fast transition between the passband and stopband - but we could just as well use a less rapid, but more monotonic roll-off. So the gain at 50Hz might be higher, but at 200Hz, we could perhaps do better with this approach.
3. The loop shape between 10 and 30Hz that the optimizer outputs seems a but weird to me - it doesn't really quite converge to a bandstop. Need to figure that out.
13289   Mon Sep 4 16:30:06 2017 gautamUpdateLSCOplev loop tweaking

Now that the DRMI locking seems to be repeatable again, I want to see if I can improve the measured MICH noise. Recall that the two dominant sources of noise were

1. BS Oplev loop A2L - this was the main noise between 30-60Hz.
2. DAC noise - this dominated between ~60-300Hz, since we were operating with the de-whitening filters off.

In preparation for some locking attempts today evening, I did the following:

1. Added steeper elliptic roll-off filters for the ITMX and ITMY Oplevs. This is necessary to allow the de-whitening filters to be turned on without railing the DAC.
2. Modified the BS Oplev loop to also have steeper high-frequency (>30Hz) roll off. The roll-off between 15-30Hz is slightly less steep as a result of this change.
3. Measured all Oplev loop TFs - UGFs are between 4 Hz and 5 Hz, phase margin is ~30degrees. I did not do any systematic optimization of this for today.
4. Went into the Foton filter banks for all the coil output filters, and modified the "Output" settings to be on "Input crossing", with a "Tolerance" of 10 and a "Timeout" of 3 seconds. These settings are to facilitate smooth transition between the two signal paths (without and with coil-dewhitening). The parameters chosen were arbitrary and not optimized in any systematic manner.
5. After making the above changes, I tried engaging the de-whitening filters on ITMX, ITMY and BS with the arms locked. In the past, I was unable to do this because of a number of issues - Oplev loop shapes and Foton settings among them. But today, the switching was smooth, the single arm locks weren't disturbed when I engaged the coil de-whitening.

Hopefully, I can successfully engage a similar transition tonight with the DRMI locked. The main difference compared to this daytime test is going to be that the MICH control signal is also going to be routed to the BS.

Tasks for tonight, if all goes well:

1. Lock DRMI.
2. Use UGF servos to set the overall loop gains for DRMI DoFs.
3. Reduce PRCL->MICH and SRCL->MICH coupling.
4. Measure loop shapes of all DRMI DoFs.
5. Make sensing matrix measurement.

Unrelated to this work: the PMC was locked near the upper rail of the PZT, so I re-locked it closer to the middle of the range.

 Quote: Surprisingly, there was no evidence of REFL55 behaving weirdly tonight, and I was able to easily lock the DRMI on 1f error signals using the recipe I've been using in the last few months.
9220   Tue Oct 8 08:58:16 2013 SteveUpdateSUSOplev power spectrums

 Quote: Just plot. RA: I'm not sure how to interperet this; I think that the SUM channel is divided by the SUM so that this is supposed to be RIN, but not sure. Can someone please take a look into the SUS model and then explain in the elog what the SUM normalization algorithm is?

PRM is dark. PRM and SRM oplev servos are off. ETMY is not centered.

9241   Tue Oct 15 15:25:13 2013 SteveUpdateSUSOplev power spectrums bandwidths

Atm1 bandwidth 0.01 Hz ETMY plot is different from

Atm2 bandwidth 0.1 Hz  normal ???????    They should be the same !!!!

9230   Thu Oct 10 11:30:15 2013 SteveUpdateSUSOplev power spectrums: PIT-YAW

Power spetrum of ETMX and ETMY in the view of oplev  pitch and yaw.

13971   Fri Jun 15 09:14:42 2018 SteveUpdateGeneralOplev sums

Oplev sums of 240 days.

 Quote: Since there have been various software/hardware activity going on (stack weighing, AUX laser PLL, computing timing errors etc etc), I decided to do a check on the state of the IFO. c1susaux, c1aux and c1iscaux crates were keyed as they were un-telnet-able. Single arm locking worked fine, TT alignment was tweaked (as these had drifted due to the ADC failure in c1lsc) to maximize Y arm transmission using the dither servos. Arms weren't staying locked for extended periods of time. I particularly suspected ITMX, as I saw what I judged to be excess motion on the Oplev. @Steve - ITMX and BS HeNes look like they are in need of replacement judging by the RIN (although the trend data doesn't show any precipitous drop in power). If we are replacing the BS/PRM Oplev HeNe, might be a good time to plan the inejction path a bit better on that table. RIN in Attachment #1 has been normalized by the mean value of the OL sum channel. There is now a script to make this kind of plot from NDS in the scripts directory (as I found it confusing to apply different calibrations to individual traces in DTT).

7808   Tue Dec 11 09:31:47 2012 AyakaUpdateLSCOplev update for improving sensitivity

Motivation

We observed that oplev servos affect the arm spectra badly (elog #7798). Some of them are fixed, but still they inject noise into the arms.
So I tried to turn the oplevs off and to see the acoustic noise effect. However, the mirrors moves so much that the signal does not seem to be linear any more, and the noise spectrum of arms changes especially around 60 - 100 Hz as you can see the spectrogram of YARM error signal below. This makes it difficult to find acoustic coupling noise. Therefore, I tried to fix the oplev servos so that the noise spectra do not get worse when the oplev servos are on.

Checking oplev UGFs

I checked the oplev open loop transfer functions. The UGFs of oplevs are all around 1-3Hz and phase margin looks enough except the BS oplev.
The gain of the BS oplev OLTF has so low that the signal is not fed back. Moreover, there is much phase delay in the BS feedback loop than the others'.
The counts of BS oplev sum is not changed so much for this 4 months, so the oplev beam seems to hit the BS correctly.
I am not sure what makes difference.

Clipped oplev beam fixed

Den and I found the output beam of ETMY oplev was clipped the other day. Also I found the scattered beam of ITMY oplev was on the edge of the mirror inside the vacuum and it made more scattered lights.
(before) -> (after)

I fixed both of the clipped beam. But still the oplev feedback inject the noise into the arm. (red: oplev off, blue: oplev on)

7812   Tue Dec 11 21:53:37 2012 AyakaUpdateLSCOplev update for improving sensitivity

[Rana, Ayaka]

The BS oplev pitch feedback came back.

The problem was that 300^2:0 filter was off. And I turned on all the low pass filters (ELP35), then the oplev servo does not seem to inject big noise into the arms as long as I see the spectra of POY and POX. These low-pass filters will be modified tomorrow so that the acoustic coupling noise is minimized.

1234   Fri Jan 16 18:29:08 2009 YoichiUpdateSUSOplevs QPDs centered
Kakeru centered ITMX and BS optical levers with the help of Jenne on the walkie-talkie.
6743   Fri Jun 1 14:56:08 2012 JamieUpdateSUSOplevs all different, messed up

For some reason the state of the oplevs is completely different for almost every suspension.  They have different sets of filters in the bank, and different filters engaged.  wtf?  How did this happen?  Is this correct?  Do we expect that the state of the oplevs should be different on all the different suspensions?  I wouldn't have thought so.

I discovered this because the PRM is unstable with the oplevs engaged.  I don't think it was yesterday.  Is something hidden changing the oplev settings?

6745   Fri Jun 1 19:48:54 2012 ranaUpdateSUSOplevs all different, messed up

Its a good question, but the answer is yes. At some level all of the OL servos should be different to handle the different mechanical resonances of the suspension as well as the optical table's acoustic noise and the different noise requirements for the difference optical cavities.

However, it would be better to have the same basic structure and then one or two customization filters.

16877   Thu May 26 19:55:43 2022 yutaConfigurationBHDOplevs centered, BHD DCPDs are now online

[Paco, Yuta]

We have aligned the IFO (except for LO-AS and GRY), and centered all the oplevs.
We have also restored Gautam's in-air BHD DCPD setup and placed it to ITMY table.
BHD DC PD signals are now online at C1:XO4-MADC1_EPICS_CH4 and CH5.

Oplevs:
Aligned the IFO following the steps in elog 40m/16875.
When we were woking on BHD DCPDs, we lost REFL beam on camera and both arms flashing. Alignment was restored mostly with TT2 pitch.
We centered all the oplevs after the recovery (see attached).

BHD DCPDs:
1. We removed a circuit box with M2 ISS photodetector readout board from AP table, in-air BHD photodiodes from optics graveyard. (see LIGO-E2000436 and elog 40m/15493 for wiring diagram)
2. Taken out temporary two Thorlabs PDA100A used for aligning LO-AS during the vent from ITMY table, and placed the BHD setup in ITMY table (see attached and attached).
3. DB9 cable (15ft+10ft) was connected from M2 ISS box to anti-aliasing chassis for ADC1 of C1X04 at 1Y2 rack (see attached).
4. +/-18V power for M2 ISS box was supplied from 1Y1 rack.
5. BHD DCPD signals are now available at C1:XO4-MADC1_EPICS_CH4 and CH5 (see attached).

Next:
- Tweak alignment of green Y input to follow Yarm
- Do LO-AS alignment
- Centering of PDs everywhere with IFO aligned
- Update RTS model for BHD

2352   Fri Dec 4 21:48:01 2009 JenneUpdateoplevsOplevs centered, IP_POS and IP_ANG centered

[Jenne Koji]

We aligned the full IFO, and centered all of the oplevs and the IP_POS and IP_ANG QPDs.  During alignment of the oplevs, the oplev servos were disabled.

Koji updated all of the screenshots of 10 suspension screens.  I took a screenshot (attached) of the oplev screen and the QPD screen, since they don't have snapshot buttons.

We ran into some trouble while aligning the IFO.  We tried running the regular alignment scripts from the IFO_CONFIGURE screen, but the scripts kept failing, and reporting "Data Receiving Error".  We ended up aligning everything by hand, and then did some investigating of the c1lsc problem.  With our hand alignment we got TRX to a little above 1, and TRY to almost .9 . SPOB got to ~1200 in PRM mode, and REFL166Q got high while in DRM (I don't remember the number). We also saw a momentary lock of the full initerferometer:   On the camera view we saw that Yarm locked by itself momentarily, and at that same time TRX was above 0.5 - so both arms were locked simultaneously.   We accepted this alignment as "good", and aligned all of the oplevs and  QPDs.

It seems that C1LSC's front end code runs fine, and that it sees the RFM network, and the RFM sees it, but when we start running the front end code, the ethernet connection goes away.  That is, we can ping or ssh c1lsc, but once the front end code starts, those functions no longer work.  During these investigations, We once pushed the physical reset button on c1lsc, and once keyed the whole crate.  We also did a couple rounds of hitting the reset button on the DAQ_RFMnetwork screen.

2353   Fri Dec 4 23:17:55 2009 robUpdateoplevsOplevs centered, IP_POS and IP_ANG centered

 Quote: [Jenne Koji]  We aligned the full IFO, and centered all of the oplevs and the IP_POS and IP_ANG QPDs.  During alignment of the oplevs, the oplev servos were disabled. Koji updated all of the screenshots of 10 suspension screens.  I took a screenshot (attached) of the oplev screen and the QPD screen, since they don't have snapshot buttons. We ran into some trouble while aligning the IFO.  We tried running the regular alignment scripts from the IFO_CONFIGURE screen, but the scripts kept failing, and reporting "Data Receiving Error".  We ended up aligning everything by hand, and then did some investigating of the c1lsc problem.  With our hand alignment we got TRX to a little above 1, and TRY to almost .9 . SPOB got to ~1200 in PRM mode, and REFL166Q got high while in DRM (I don't remember the number). We also saw a momentary lock of the full initerferometer:   On the camera view we saw that Yarm locked by itself momentarily, and at that same time TRX was above 0.5 - so both arms were locked simultaneously.   We accepted this alignment as "good", and aligned all of the oplevs and  QPDs. It seems that C1LSC's front end code runs fine, and that it sees the RFM network, and the RFM sees it, but when we start running the front end code, the ethernet connection goes away.  That is, we can ping or ssh c1lsc, but once the front end code starts, those functions no longer work.  During these investigations, We once pushed the physical reset button on c1lsc, and once keyed the whole crate.  We also did a couple rounds of hitting the reset button on the DAQ_RFMnetwork screen.

A "Data Receiving Error" usually indicates a problem with the framebuilder/testpoint manager, rather than the front-end in question.  I'd bet there's a DTT somewhere that's gone rogue.

2354   Sat Dec 5 01:40:11 2009 KojiUpdateoplevsOplevs centered, IP_POS and IP_ANG centered

We restarted daqd and it did restored the problem
http://lhocds.ligo-wa.caltech.edu:8000/40m/Computer_Restart_Procedures#fb40m
Then restart the 'daqd' process:'telnet fb40m 8087', type "shutdown" at the prompt. The framebuilder will restart itself in ~20s.

It did not related to the problem, but we also cleaned the processes related to dtt, dataviewer by pkill

After that the alignment scripts started to work again. As a result, we got some misalignment of the oplevs.
I am going to come on Sunday
- Align the optics
- Align the oplevs again
- Take snapshots for the suspensions
- Align the IP_POS, IP_ANG
- Align the aux laser for the absolute length
- Align PSL table QPDs, and MCT QPD

2358   Sat Dec 5 18:23:48 2009 KojiUpdateoplevsOplevs centered, IP_POS and IP_ANG centered

NOTE: HEPA is on at its full.

[[[OK]]] Align the suspended optics (by Rob) [[[OK]]] Align the oplevs again [[[OK]]] Take snapshots for the suspensions/QPDs/IO QPDs/PZT strain gauges [[[OK]]] Align the IP_POS, IP_ANG [[[OK]]] Align the PSL table QPDs, the MC WFS QPDs, and the MCT QPD [[[OK]]] Align the aux laser for the absolute length

### Alignment of the aux laser

o Go to only ITMX mode:
Save the alignment of the mirrors. Activate X-arm mode. Misalign ITMY and ETMX.

o Inject the aux beam:
Open the shutter of the aux NPRO. Turn the injection flipper on.

o Look at the faraday output:
There are several spots but only one was the right one. Confirm the alignment to the thorlabs PD. Connect the oscilloscope to the PD out with a 50Ohm termination.
Thanks to the Alberto's adjustment, the beat was already there at around 10MHz. After the PD adjustment, the DC was about 600mV, the beat amplitude was about 50mVpp.

o Adjust the aux beam alignment:
Adjust the alignment of the aux beam by the steering mirrors before the farady isolator. These only change the alignment of the aux beam independently from the IFO beam.
After the alignment, the beat amplitude of 100mVpp was obtained.

o Closing
Close the shutter of the NPRO. Turn off the flipper mirror. Restore the full alignment of the IFO.

11142   Sat Mar 14 00:12:18 2015 ranaUpdateSUSOplevs huh?

The oplev situation still seems unresolved - notice this DTT. I guess there are still inconsistencies in the screens / models etc.

Could use some some investigation and ELOGGING from Eric.

6533   Fri Apr 13 01:27:10 2012 JenneUpdateSUSOplevs recentered

It's been a while since I think anyone has done it, and several optics were pretty far from centered, so I centered all of the oplevs except for SRM.

I am confident about my arm alignment, MICH and PRC (so BS, ITMX, ITMY, PRM, ETMX and ETMY), but I wasn't sure if I was getting SRC right, so I didn't touch the SRM's oplev.

Suresh removed all of the IPPOS measurement optics, so there was nothing blocking the BS and PRM oplevs.

However, the PRM oplev was ridiculously bad, and I don't know how long it's been that way.  Some of the optics shooting the beam into the chamber weren't optimally aligned, so the beam coming out of the chamber was hitting the lowest edge of the optic mount, for the first optic the beam encountered.  I adjusted the mirror launching the beam into the chamber by a teeny bit, so that the outcoming beam was ~horizontal and hitting the center of the first steering mirror in pitch.  I had to move that steering mirror a little to the right (if you are staring at the HR face of the mirror), to get the beam to come close to the horizontal center of the optic.  Then I proceeded to do normal oplev alignment.

Also, I've noticed lately that ITMX is noisier than all the other optics.  It's kind of annoying.  The sensor RMS values reported for the ITMX watchdogs for UL and LL are rarely below 2, and are often (~70% of the time?) above 3.  The SD RMS is a normal 1-ish.

6744   Fri Jun 1 18:07:32 2012 steveUpdateSUSOplevs servo values

 Quote: For some reason the state of the oplevs is completely different for almost every suspension.  They have different sets of filters in the bank, and different filters engaged.  wtf?  How did this happen?  Is this correct?  Do we expect that the state of the oplevs should be different on all the different suspensions?  I wouldn't have thought so. I discovered this because the PRM is unstable with the oplevs engaged.  I don't think it was yesterday.  Is something hidden changing the oplev settings?

As of February 23, 2012 when oplev PIT and YAW transfer functions were taken

 OPLEV SERVO 300^ 2:0 BR ELP RLP RES GAIN QPD counts OD mm ETMY pit 300^ 2:0 BR 35 80 0.5 -1.5 15,500 ~1 ETMY yaw 300^ 2:0 BR 35 80 0.6 -1.0 ETMX pit 300^ 2:0 BR 35 80 0.5 0.5 1,500 ~1.5 ETMX yaw 300^ 2:0 BR 35 80 0.6 1.0 ITMY pit 300^ 2:0 BR 80 2.0 15,000 ~2.5 ITMY yaw 300^ 2:0 BR 80 -4.0 ITMX pit 300^ 2:0 BR 80 1.0 1,350 ~1.5 ITMX yaw 300^ 2:0 BR 80 -2.0 BS pit 300^ 2:0 BR 50 0.5 3,500 ~1 BS yaw 300^ 2:0 50 3.3 -1.0 PRM pit 300^ 2:0 BR 3.3 1.0 4,000 ~2 PRM yaw 300^ 2:0 BR 35 3.3,  4 -0.5 SRM pit 300^ 2:0 BR 40 -2.0 2,600 ~2.5 SRM yaw 300^ 2:0 BR 40 2.0

6535   Sat Apr 14 00:19:35 2012 SureshOmnistructureLSCOptical Fibers for insitu RFPD characterisation

I have worked out the fibers we need to get for the following distribution scheme:

1) We have a laser placed at the 1Y1 rack.  A part of the power is split off for monitoring the laser output and sent to a broadband PD also placed in the same rack.  The RF excitation applied to the laser is split and sent to LSC rack (1Y2) and used to calibrate the full PD+Demod board system for each RFPD.

2) A single fiber goes from the laser to a 11+ way switch located in the OMC electronics cabinet next to the AP table.  From here the fibers branch out to three different tables.

 Table / Rack RF PDs on the table Number of PDs Fiber Length from OMC The AP table AS11,AS55,AS165,REFL11,REFL33,REFL55,REFL165 7 6 m The ITMY table POY11 1 12 m The ITMX table POX11, POP22/110 and POP55 3 20 m

Cable for the laser source to the OMC table:

 The 1Y1 Rack to OMC rack AM Laser Source to Switch 25 m

We also require a cable going from PSL table to the ETMY table:   This is not a part of the RFPD characterisation.  It is a part of the PSL to Y-end Aux laser lock  which is a part of the green locking scheme.  But it is  fiber we need and might as well order it now along with the rest.

 PSL Table to ETMY Table PSL to ETMY Aux laser 75m

If you would like to add anything to this layout / scheme, please comment.  On Monday Eric is going to take a look at this and place orders for the fibers.

(I have included the lengths required for routing the fibers and added another 20% to that )

12695   Sun Jan 8 12:47:06 2017 ranaUpdateGeneralOptical Layout in DCC

Manasa pointed me to the CAD drawings in the 40m SVN and I've now uploaded them to the 40m DCC Tree so that EricG and SteveV can convert them into SolidWorks.

12697   Mon Jan 9 16:12:30 2017 SteveUpdateGeneralOptical Layout in DCC

Caltech Facilities promissed to email the 40m facility drawings in Cad format.

I organized the old of optical , vacuum and facility layout drawings on paper in the old cabinet.

 Quote: Manasa pointed me to the CAD drawings in the 40m SVN and I've now uploaded them to the 40m DCC Tree so that EricG and SteveV can convert them into SolidWorks.

561   Wed Jun 25 00:35:40 2008 KojiSummaryGeneralOptical Layout on the AP table
I have visited the AP table in order to investigate where we are going to put the optical setup for the abs. length meas.
I have attached the PNG and PDF files to share the optical layout. It is not complete. Any comments or corrections are welcome.
9943   Mon May 12 22:52:59 2014 JenneSummarySUSOptical Lever Filters are all different

We need to go back and have a look at all of our optical lever control filters, and make sure they make sense.

In particular, we should have a look at the ITMs, since they have a huge amount of motion around 10Hz.

Notes:  ETMX shouldn't have that lower notch.  The bounce mode Qs should be lowered.

8480   Tue Apr 23 22:59:05 2013 ranaConfigurationSUSOptical Lever Gains normalized

Due to the recent addition of cal factors in the OL error points, the OLPIT_GAIN and OLYAW_GAIN have been reduce to tiny numbers (e.g. 0.002).

Since our MEDM only shows 3 digits past the decimal point by default, it makes more sense to have the gains around 1.

So I reduced the gains in all of the FM1 filters from 1000 to 1 and multiplied the GAIN values by 1000 (using ezcastep) to compensate.

All of the active optics seem to be behaving as before. Haven't tested ETMs or SRM yet.

9934   Fri May 9 01:36:28 2014 ranaSummarySUSOptical Lever QPD Sum trends: they're almost all too weak

We want there to be ~16000 cts of signal per quadrant on the optical levers. I think that most of the QPDs have been modified to have 100k transimpedance resistors.

From the attached 90 day trend, you can see that the ETMX, BS, PRM, and SRM are really low. We should figure out if we need to change the lasers or if the coating reflectivities are just low.

Steve, can you please measure the laser powers with a power meter and then reply to this entry?

Another possibility is that we are just picking a dim beam and a brighter one is available.

9942   Mon May 12 22:42:19 2014 ranaSummarySUSOptical Lever QPD Sum trends: they're almost all too weak

For some reason or another, I decided that we should see if the optical lever servos were injecting too much noise into the test masses. The ITMs are much worse than the ETMs and I am afeared that they might be making the main noise for our arms in the 20-40 Hz region. Jenne is checking up on these feedback loops to see what's up.

To estimate the actuator gains of the mirrors, I turned on 1 count drives from LSC/CAL oscillators into the LSC drives of each test mass at the frequencies shown in the plot with the resulting peaks showing up in in POX/Y with the single arm locks in red. I will leave these going permanently, but with 0.1 count ampltiudes; we need to make it so in the scripts.

7516   Wed Oct 10 02:20:34 2012 ranaUpdateSUSOptical Lever QPD mods

Since we upgraded the CDS system, I guess our ADC ranges have gone up but we never did anything to the OLs to match the ADC ranges. From Liz's daily summary page of the OL, I see this:

So we need a factor of 5-10 increase in the electronics gain (why isn't the BS SUM on there?). This might be accomplished in the head, but for the ones with whitening boards, might be better to do there.

485   Sun May 18 18:44:48 2008 ranaSummarySUSOptical Lever SUM Trend - 80 days
I used the OL-Trend.xml dataviewer template to make this plot. Looks like the ETMY optical lever
slowly degraded over the last few months and then finally died 10 days ago. Would someone please
replace this laser and tune the lens position to minimize the spot size on the quad?
5376   Sat Sep 10 11:07:37 2011 ranaHowToSUSOptical Lever Servo Tuning thoughts

Now that we are in a moderately stable condition, its time to design the optical lever feedback transfer functions. We should think carefully about how to do this optimally.

In the past, the feedback shape was velocity damping from 0-10 Hz, with some additional resonant gain around the pendulum and stack modes. There were some low pass filters above ~30 Hz. These were all hand tuned.

I propose that we should look into designing optimal feedback loops for the oplevs. In principle, we can do this by defining some optimal feedback cost function and then calculate the poles/zeros in matlab.

How to define the cost function (? please add more notes to this entry):

1) The ERROR signal should be reduced. We need to define a weight function for the ERROR signal: C_1(f) = W_1(f) * (ERR(f)^2)

2) The OL QPDs have a finite sensing noise, so there is no sense in suppressing the signal below this level. Need to determine what the sensing noise is.

3) The feedback signal at high frequencies (30 Hz < f < 300 Hz) should be low passed to prevent adding noise to the interferometer via the A2L coupling. It also doesn't help to reduce this below the level of the seismic noise. The cost function on the feedback should be weighted apprpriately given knowledge about the sensing noise of the OL, the seismic noise (including stack), and the interferometer noise (PRC, SRC, MICH, DARM).

4) The servo should be stable: even if there is a negligible effect on the ERROR signal, we would not want to have more than 10 dB of gain peaking around the UGFs.

5) The OL QPDs are dominated by drift of the stack, laser, etc. at some low frequencies. We should make sure the low frequency feedback is high passed appropriately.

6) Minimize transmitted power rms in single arm lock etc.

6442   Sun Mar 25 20:13:31 2012 ranaHowToSUSOptical Lever Servo Tuning thoughts

To start the optical lever filter design, I looked into the noise on ITMY. It should be similar to the other arm cavity optics since they have the same whitening electronics.

The RED/BLUE are with loops open. The MAGENTA/CYAN with loops closed. Looks good; the bandwidth is a few Hz and there is not much peaking,

To figure out the contribution from the dark noise I misaligned the ITMY until the sum on the QPD went to zero. Then I took the spectra of the OL{1,2,3,4}_OUT signals (they all looked the same).

To normalize them properly I took OL4, multiplied it by 2 to account for the incoherent sum of 4 channels and then divided by the nominal SUM (which was 14685 counts). I've left the OL3 un-normalized to show the ratio.

From this plot it seems that the dark noise is not a problem at any frequency (no need to amplify for the new ADCs).

I'm going to use the open loop spectra to design the optimal feedback control. The file is saved as /users/rana/dtt/ITMY_OL-120325.xml

9946   Tue May 13 13:27:58 2014 SteveSummarySUSOptical Lever Servos setting table

 Quote: For some reason or another, I decided that we should see if the optical lever servos were injecting too much noise into the test masses. The ITMs are much worse than the ETMs and I am afeared that they might be making the main noise for our arms in the 20-40 Hz region. Jenne is checking up on these feedback loops to see what's up. To estimate the actuator gains of the mirrors, I turned on 1 count drives from LSC/CAL oscillators into the LSC drives of each test mass at the frequencies shown in the plot with the resulting peaks showing up in in POX/Y with the single arm locks in red. I will leave these going permanently, but with 0.1 count ampltiudes; we need to make it so in the scripts.

I'm in the process of filling this table

 OPLEV SERVO 300 ^ 2:0 BR 16,24 Hz ELP RLP BOOST RES GAIN QPD COUNTS QPD mW QPD beam OD HE/NE output mW % back on QPD ETMY PIT FM1 FM5 55 -30 8,200 0.2 3.3 YAW FM1 FM5 55 -28 ETMX PIT FM1 FM5 35 4.4 900 0.2 1.7 YAW FM1 FM5 35 2.1 ITMY PIT FM1 FM5 3.3 52 14,400 0.4 9.5 YAW FM1 FM5 3.3 -46 ITMX PIT FM1 FM5 50 3.3 30 7,400 0.17 2.8 YAW FM1 FM5 50 3.3 -20 BS  PIT FM1 FM5 35 3.3 9 2,800 0.05 2.8 YAW FM1 FM5 35 3.3 -9 PRM  PIT FM1 FM5 55 FM7 3.3 7 3200 0.06 2.8 YAW FM1 FM5 55 FM7 3.3 -5 SRM  PIT FM1 -20 9.5 YAW FM1 20

I should replace ETMX He/Ne laser

9145   Fri Sep 20 09:49:06 2013 SteveUpdateSUSOptical Lever Trend for 180 days: bad ETMY & PRM

I'm working on it.

9143   Thu Sep 19 21:42:18 2013 ranaUpdateSUSOptical Lever Trend for 90 days: ETMX and PRM are the bad ones

We found that that bounce (16.1 Hz) and roll (23.5 Hz) modes on the ITMX were much higher than on the ITMY. After some checking, it seems that the bandstop filters for the

SUSPOS, SUSPIT, SUSYAW, and SUSSIDE loops are set to the correct frequencies. However, the OLPIT and OLYAW had not been set correctly. I have copied the SUS filters into the OL filterbanks and reloaded all the filter banks. Attached are the comparison of old, bad, OL with the SUS ones.

The same cockamamie situation was there for the BS & ITMY as well. Although we still don't have the roll mode frequencies listed in the mechanical resonances wiki, I have guessed that the ITMY roll frequency is the same as the ITMX, since they have nearly the same bounce frequency. OL filters for the BS & ITMY are now at the right frequency (probably). Keiko is on top of fixing things for the other optics.

I think this whole notching adventure was in Leo's hands several months ago, but WE forgot to point him at the OLs in addition to the SUS. I blame Kiwamu 50% for not supervising him and Koji by 45% for not supervising Kiwamu. The other 5% goes to someone else. You know who you are.

168   Wed Dec 5 18:08:36 2007 AndreyUpdateASCOptical Lever laser for ETMX is installed

A new laser with \lambda=633nm has been intalled and the mirror adjusted so that the signal hits the center of the photodetector.

Output power level of that laser is 3.45 +- 0.05 mW.

Only about 0.29mW hits the photodetector.

Cable clips have been used to firmly fix the power supply cable for the laser.

See attached photopicture of the ETMX - "oplev" - optical - table.
8505   Mon Apr 29 15:53:49 2013 AlbertUpdateoptical tablesOptical Table Boxes

These are the tentative box placements. Roughly. I don't actually have the box finalized yet, but the box should be around that size.

AS1

BSPRM

ETMX

ETMY

MC2

POX

POY

How do I perspective ._.

8342   Mon Mar 25 18:58:09 2013 Albert YangUpdateoptical tablesOptical Table Toolboxes

For those of you who spend annoying amounts of time looking for tools, fear no more. Toolboxes for each optical table are coming!

They will probably have:

IR Viewer (a few optical tables will have IR viewers, these specific tables will be labeled in the diagram coming out later)

IR Card

Ball screw drivers (3/16 in.) 6-8 in. handle

SMA Wrench

Allen Keys

Flashlight

Various Connectors (I'll find out what's needed at some point)

Zip Ties

Small flat screwdrivers (for adjusting camera gains)

Please suggest what else may be needed in these boxes.

The boxes will be held to the side of the tables, either by magnets or screws. A diagram of where they will be placed on each optical table in order to minimize obstruction of walkways will be distributed soon. Any objections can then be noted.

8382   Mon Apr 1 16:16:16 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes)

The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated.

In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged.

A diagram of tentative box placements will go out soon.

8384   Mon Apr 1 16:35:42 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

 Quote: A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes) The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated. In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged. A diagram of tentative box placements will go out soon.

I also took every allen key I can find so they can be sorted. They will be back in the appropriate drawer locations soon.

8395   Tue Apr 2 21:11:42 2013 RanaUpdateoptical tablesOptical Table Toolboxes Update

 Quote: A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes) The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated. In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged. A diagram of tentative box placements will go out soon.

No, the small boxes must be attached to the optical tables. They won't be heavy enough to change the table tilt.

Also, all tools must be color coded according to the optical table using the 3M Vinyl table color code:

http://www.3m.com/product/images/Vinyl-Electrical-Color-Tape-300.jpg

8408   Wed Apr 3 19:01:06 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

Quote:

 Quote: A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes) The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated. In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged. A diagram of tentative box placements will go out soon.

No, the small boxes must be attached to the optical tables. They won't be heavy enough to change the table tilt.

Also, all tools must be color coded according to the optical table using the 3M Vinyl table color code:

http://www.3m.com/product/images/Vinyl-Electrical-Color-Tape-300.jpg

Ok.

So the new tentative plan on the boxes is to bolt them (magnetic strips were proposed but overruled on the grounds that they're not strong enough to withstand being knocked down by accidents).

The boxes are going to be a mix of the Thorlabs Benchtop Organizer (http://www.thorlabs.com/thorProduct.cfm?partNumber=BT17) and the original box. The box will have a region covered in mesh, so tools can be placed and held there. The box will also have a spacer at the bottom, with another mesh right above it, lined up. However, this double-mesh will only cover half of the box. The other half of the box will be compartmentalized to hold things such as screws, connectors, etc. I will talk to Steve about building the boxes.

Also, using nail-polish to coat the Allen wrenches is not going to work. Nail polish does not stick easily enough. The tentative new plan is oil paint, but this is to be reviewed.

Finally, the diagram with the placement of the boxes relative to the optical tables has been put on paper, but needs to be computerized so it's easier to read. This will be done as soon as possible.

8410   Wed Apr 3 23:22:20 2013 ranaUpdateoptical tablesOptical Table Toolboxes Update

There are some tips for how to appy nail polish on YouTube from MKNails and MissJenFABULOUS. Their tips on how to prepare the site for a strong bonding strength are probably helpful for our gold/nickel coated tools. For chrome tools we may need to abrade the surface with a stone or fine sandpaper for it to take the layer better. IF the YouTube videos don't do it for you, then I suggest contacting Tom Evans at LLO to find out what kind of nail polish he uses.

8445   Thu Apr 11 16:29:23 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

 Quote: There are some tips for how to appy nail polish on YouTube from MKNails and MissJenFABULOUS. Their tips on how to prepare the site for a strong bonding strength are probably helpful for our gold/nickel coated tools. For chrome tools we may need to abrade the surface with a stone or fine sandpaper for it to take the layer better. IF the YouTube videos don't do it for you, then I suggest contacting Tom Evans at LLO to find out what kind of nail polish he uses.

This is the tentative box placement per optical table. The toolboxes are going to be color-coded by a combination of two colors (the order won't matter). The side of each toolbox will have a little panel to let you know which box corresponds to which set of colors.

On the diagram, the set of colors is simply the color of the box border and the color of the text.

If anyone has a problem with any of the colors or the box placement let me know before they are installed and become an annoyance:

Box Placements:

ETMY: Box will be attached to the underside of the table by magnets. The box will be on the north side of the optical table.

POY: Box will be attached to the side of the optical table by magnets. The box will be on the west side of the optical table.

BSPRM: Box will be attached to the side of the optical table by magnets. The box will be on the west side of the optical table.

AS: Box will be attached to the side of the optical table by magnets. The box will be on the north side of the optical table.

PSL1: Box will be inside the optical table, in the northeast corner.

PSL2: Box will be inside the optical table, in the southwest corner.

POX: Box will be attached to the side of the optical table by magnets. The box will be on the south side of the optical table.

MC2: Box will be attached to the side of the optical table by magnets. The box will be on the south side of the optical table.

ETMX: Box will be attached to the side of the optical table by magnets. The box will be on the east side of the optical table.

8457   Mon Apr 15 17:44:28 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

I decided to go see what the electrical tape looks like on the other tools.

These are the tools I felt were necessary to label with tape: (the others don't seem to be terribly important in terms of not interchanging between boxes)

On another note I'm not sure why electrical tape can't be used on the Allen Wrenches too.

I also plan on ordering smaller flash lights for each table (this one is bulky and unwieldy), and filling in the gaps of the Allen Wrench sets as soon as I get the go-ahead.

8502   Mon Apr 29 08:17:40 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

 Quote: I decided to go see what the electrical tape looks like on the other tools. These are the tools I felt were necessary to label with tape: (the others don't seem to be terribly important in terms of not interchanging between boxes) On another note I'm not sure why electrical tape can't be used on the Allen Wrenches too. I also plan on ordering smaller flash lights for each table (this one is bulky and unwieldy), and filling in the gaps of the Allen Wrench sets as soon as I get the go-ahead.

11006   Wed Feb 11 18:44:53 2015 manasaUpdateGeneralOptical fiber module

I have moved the optical fiber module for FOL to the PSL table. It is setup on the optical table right now for testing.

Once tests are done, the box will move to the rack inside the PSL enclosure.

While doing any beat note alignment, please watch out for the loose fibers at the north side of the PSL enclosure until they are sheilded securely (probably tomorrow morning).

16445   Tue Nov 2 18:54:41 2021 Anchal, PacoUpdateBHDOptical fibres laid for BHD upgrade

We successfully laid down all required optical fibre fiber cables from 1X4-1X7 region to 1Y1-1Y3 region today. This includes following cables:

• Timing fibre fiber from Master Timing Synchornizer D050239 on 1X6 to C1SU2 I/O chassis on 1Y1.
• Timing fibre fiber from Master Timing Synchornizer D050239 on 1X6 to C1BHD I/O chassis on 1Y3.
• CX4 cable from Dolphin Card on 1X4 to C1SU2 FE on 1Y1 for IPC.
• CX4 cable from Dolphin Card on 1X4 to C1BHD FE on 1Y3 for IPC.
• DAQ Network extension fibre fiber optic cable from DAQ Network Switch on 1X7 to another switch we mounted on 1Y3 for local DAQ network distribution.
17274   Wed Nov 16 18:41:17 2022 yutaSummaryBHDOptical gain calibrations for BHD MICH

Optical gains of AS55 and BH55 are calibrated for BHD MICH.

LO-ITM single bounce:
With LO-ITM signle bounce fringe, optical gain of BH55_Q is measured using a method similar to MICH calibration in AS55 (40m/16929).
Demodulation phase for BH55 is tuned to minimize I when LO-ITM is freeswinging (using getPhaseAngle.py).
(Notebook: /opt/rtcds/caltech/c1/Git/40m/scripts/CAL/BHD/BHDOpticalGainCalibration.ipynb)
Results are the following:

LO-ITMY fringe: 7.84e9 counts/m (demod phase 147.1 +/- 0.3 deg) See Attachment #1
LO-ITMX fringe: 8.44e9 counts/m (demod phase 149.6 +/- 0.4 deg) See Attachment #1

Difference in the optimal demodulation phase 2.5 +/- 0.5 deg agrees with half of Schnupp asymmetry, as expected (40m/17007).
Difference in the optical gain for LO-ITMY and LO-ITMX is probably from statistical fluctuation.

BHD MICH:
Sensing matrix was measured by injecting a line at BS (300 counts @ 211.1 Hz), LO1 (5000 counts @ 287.1 Hz) and AS1 (5000 counts @ 281.79 Hz), when MICH is locked with AS55_Q and LO PHASE is locked with BH55_Q (both with no offset).
Using the sensing matrix, demodulation phase was tuned to minimize I phase for MICH signal in AS55 and LO1 signal in BH55.
After the demodulation phase tuning. sensing matrix was measured to be the following.
See, also Attachment #3 for injected peaks. I phase signal is successfully suppressed by at least an order of magnitude.
(Notebook: /opt/rtcds/caltech/c1/Git/40m/scripts/CAL/SensingMatrix/MeasureSensMatBHD.ipynb)

Sensing Matrix with the following demodulation phases (counts/counts) {'AS55': -160.15695076011946, 'BH55': 154.13916838400047}       Sensors           MICH @211.1 Hz          LO1 @287.1 Hz            AS1 @281.79 Hz            C1:LSC-AS55_I_ERR_DQ    1.22e-05 (120.53 deg)   7.24e-07 (85.64 deg)     1.26e-06 (40.42 deg)     C1:LSC-AS55_Q_ERR_DQ    2.95e-03 (-101.62 deg)  1.24e-06 (-80.43 deg)    1.69e-06 (152.31 deg)     C1:LSC-BH55_I_ERR_DQ    1.28e-03 (80.95 deg)    3.44e-06 (109.31 deg)    2.22e-06 (154.40 deg)     C1:LSC-BH55_Q_ERR_DQ    7.44e-03 (77.38 deg)    2.56e-04 (-59.85 deg)    2.42e-04 (6.40 deg)     C1:HPC-BHDC_DIFF_OUT    2.21e-03 (82.45 deg)    4.37e-05 (121.87 deg)    3.61e-05 (-169.09 deg)

Using BS actuation efficiency of 26.08e-9 /f^2 m/counts (40m/16929), optical gain for AS55_Q and BHDC_DIFF for MICH is

2.95e-03 / (26.08e-9/(211.1**2)) = 5.04e9 counts/m (AS55_Q for MICH)
2.21e-03 / (26.08e-9/(211.1**2)) = 3.78e9 counts/m (BHDC_DIFF for MICH)

For AS55_Q, this is a factor of 4~5 higher than the previous measurement from free swing (40m/16929). Why?
Free swing measurement was done again, and this gave 1.24e9 counts/m, which is consistent with the previous measurement (see Attachment #3).

Using LO1 and AS1 actuation efficiencies of 3.14e-8 /f^2 m/counts (40m/17206), optical gains for BH55_Q for LO1 and AS1 are

2.56e-04 / (3.14e-8/(287.1**2)) = 6.72e8 counts/m (BH55_Q for LO1)
2.42e-04 / (3.14e-8/(281.79**2)) = 6.12e8 counts/m (BH55_Q for AS1)

Next:
- Compare them with expected values
- Measure them with different locking points (different LO phases, MICH offsets)
- Investigate why MICH optical gain in AS55 is 4~5 times higher than free swing measurement (use different modulation frequency?)

Summary of actuation calibration so far (counts from C1:LSC-xx_EXC or C1:SUS-xx_LSC_EXC):
BS   : 26.08e-9 /f^2 m/counts (see 40m/16929)
ITMX :  5.29e-9 /f^2 m/counts (see
40m/16929)
ITMY :  4.74e-9 /f^2 m/counts (see
40m/16929)
ETMX : 10.91e-9 /f^2 m/counts (see 40m/16977 and 40m/17014) ETMY : 10.91e-9 /f^2 m/counts (see 40m/16977)
MC2 : -14.17e-9 /f^2 m/counts in arm length (see 40m/16978)
MC2 :   5.06e-9 /f^2 m/counts in IMC length (see 40m/16978) LO1 : 3.14e-8 / f^2 m/counts (see 40m/17206)
LO2 : 2.52e-8 / f^2 m/counts (see 40m/17206)
AS1 : 3.14e-8 / f^2 m/counts (see 40m/17206)
AS4 : 2.38e-8 / f^2 m/counts (see 40m/17206)

ELOG V3.1.3-