According to the wiki, REFL 11 has a transimpedance of 4.08kV/A, and REFL 55 has a transimpedance of 615V/A. This is a ratio of ~6.5 . My optickle simulations from earlier this evening indicate that, at maximum, there is a ~factor of 2 more signal in REFL 11 than REFL 55. This is a factor of order 10-15. Then, REFL 55 has 15dB whitening gain, which is a factor of ~4. So, this explains why we're seeing so much more digital signal on REFL11 than REFL55.
Tomorrow, I need to replace the 50/50 beam splitter that splits the beam between REFL55 and REFL11 (33 and 165 have already had their light picked off at this point). I want to put in a 10% reflector, 90% transmission beamsplitter. Steve, can you please find me one of these, and if we don't have one, order one? This will give us a little more light on 55, and less light on 11, so hopefully we won't be saturating things anymore.
Shutter moved, no more clipping.
Pick-off mirror 2" replaced by 1" one. Laseroptik HR 532nm, incident angle 30-45 degrees, AR 532 nm
Green REFL PD moved to 4" close to pick-off mirror. Pd being close to pick-off does not separate multiple reflections on it. I'll replace Laseroptic mirror with Al one. It is not easy to find.
Hole cut into side wall for doubler oven cable to exit.
Beam trap for Pd refl is in place. Cabeling is ti·died up.
Laseroptic 1" mirror is replaced by Al 1" mirror. Problem remains the same. This diffraction patter has to be coming from the Faraday.
Atm1, good separation when Pd is far
Atm2, bad separation when Pd is close
As I always tell everyone: Don't use a 10% reflector which produce ghost beams. Use a 90% reflector.
As I always tell everyone: Don't use a 10% reflector which produce ghost beams. Use a 90% reflector.
Hmmm, yes, I forgot (bad me). I'll find a 90% refl BS, and swap the positions of REFL11 and REFL55.
I have done the swap in the REFL path. First, I swapped the positions of REFL11 and REFL55. Then, I swapped out the 50/50 BS for a 90% reflection BS. (90% goes to REFL55, 10% goes to REFL11). I also changed the aluminum dump that was dumping the old REFL165 path into a razor dump.
Before: REFL11 had 4.0mW, REFL55 had 3.1mW. Now, REFL11 has 0.53mW, and REFL55 has 6.9mW. REFL165 still has around 61mW of light, and REFL33 has 3.3mW (the things that were changed were after 165 and 33 in the REFL path).
Now, the DC value of the REFL PDs are: REFL165 = 10.4V, REFL33 = 110mV, REFL55 = 232mV, REFL11 = 18.6mV.
As I was finishing aligning the beams onto all of the REFL diodes, Manasa asked for the IFO so she and Masayuki could continue their work on the Xarm, so I'll check the signals acquired a little later.
Yes, this was not ELOG'd by me, unfortunately. This was the MC tickler which I described to some people in the control room when I turned it on.
As Koji points out, with the MCL path turned off this injects frequency noise and pointing fluctuations into the MC. With the MCL path back on it would have very small effect. After the pumpdown we can turn it back on and have it disabled after lock is acquired. Unfortunately, our LOCKIN modules don't have a ramp available for the excitation and so this will produce some transients (or perhaps we can ezcastep it for now). Eventually, we will modify this CDS part so that we can ramp the sine wave.
I've written a new TICKLE script using the newly found 'cavget' and 'cavput' programs. They are in the standard epics distribution as extension binaries. They allow multichannel read/write as well as ramping, delays, incremental steps, etc. http://www.aps.anl.gov/epics/tech-talk/2012/msg01465.php.
Running from the command line, they seem to work fine, but I've left it OFF for now. I'll switch it into the MC autolocker at some point soon.
It seems that the PRM violin mode freqs shifted from 625-ish to 640Hz.
The peaks rang up because of the servo.
Once the notch freq was shifted to 640Hz, the violin mode started to decay.
The DRMI has been locked!! And at least one time, it was for more than one minute!!
We are not 100% sure yet that it's correctly sideband locked. The test of this was to put a 50% BS in front of the AS camera (so after the beam has gone to AS55), and send the light over to a PDA10CF Thorlabs PD. I locked the Michelson on carrier for the alignment of this diode. Then I strung a cable to the control room, and plugged it into the RF spectrum analyzer. (First, I had turned off the green beat PD power, so there wasn't any RF stuff on the line that I unplugged). It's hard to watch the screen and a tv / dataviewer at the same time, so I've taken a video, so that we can see the nicely locked round DRMI beam on the AS camera, and the spectrum analyzer. My phone is working very hard at uploading the video, but we may have to wait until tomorrow for that. However, I think that we're locked on the 55MHz sideband. (Also, maybe I'm too tired or excited or something, but how do you make the real cameras take video??)
EDIT: Video uploaded. Pause the video at 10 seconds, and you'll see that we've got a strong 110MHz peak!! Hoooray! The TV in the upper right side of the video is AS. You can see as we flash, the peaks go up and down. When there's no resonance, the 110 peak goes away. (Ex., when I'm PRMI locked on the sideband, there isn't a visible peak).
Alignment procedure was as normal: Lock and align the arms. Misalign ETMs. Check that MICH fringes look good (ASS does a nice enough job that I don't actually lock and align the Michelson anymore). Restore the PRM. Lock PRMI. Tweak PRM alignment to maximize POP110I. At this point, Koji and I played a little with the PRMI, but when we finished with that, we restored the SRM, and tweaked its alignment by making nice overlap on the AS camera.
Then, we tried some DRMI settings, started seeing some locks, and played a bit with trying to optmize the settings that we have.
PRCL ASC is on (with loop triggering). MICH gain = -0.8, PRCL gain = +0.05. FM4, FM5 always on, FM2 triggered. Loop and filter module triggering on POP22I. No power normalization. MICH and PRCL locked on REFL55 I&Q, with 1's in the LSC input matrix. PRCL actuating on PRM with +1, MICH actuating on BS with +0.5, PRM with -0.267.
I took transfer functions between REFL55 I&Q and REFL11 I&Q, to determine the relative gains and signs. REFL11I's gain should be -18dB relative to REFL55I, with the opposite sign. We tried PRMI locking with MICH = 1*REFL55Q and PRCL = -0.125*REFL11I for the input matrix. Still no power normalization (we haven't used power norm at all today, so I'll quit writing that).
I took transfer functions between REFL55 I&Q and REFL33 I&Q. REFL33I's gain is -8dB relative to REFL55I, but they have the same sign. We tried locking PRMI with MICH = 1*REFL55Q and PRCL = +0.6*REFL33I. Success.
Next up, some Optickle simulations, to help us go in the right direction for DRMI locking. I checked the signs of the error signals REFL55I (PRM sweep), REFL11I (PRM sweep) and REFL55Q (MICH sweep) in both PRMI and DRMI configurations. For all of these cases, the signs were the same (i.e. no sign flips needed to happen for DRMI locking, relative to PRMI locking). I checked the sensing matrices for DRMI and PRMI for those same signals, and took the ratios of the sensing matrix elements. This gave me the ratio of optical gains for each error signal, in the DRMI case vs. PRMI case, so any servo gain changes should be the inverse of these numbers. These numbers are all DRMI/PRMI: REFL55I PRCL response = 0.76, REFL11I PRCL response = 0.99, REFL55Q MICH response = 18. So, when trying to lock the DRMI, we wanted to keep the gains for PRCL about the same, reduce the servo gain for MICH by a factor of ~20, but keep the same signs for everything.
In doing that, we started seeing some short DRMI locks, so we twiddled some parameters (mostly the elements in the LSC input matrix) a bit. We eventually settled on: PRCL = -0.125*REFL11I, MICH = 0.1*REFL55Q, and SRCL = 1.0 * REFL55I. The output matrix was the same (MICH pushing on BS and PRM, PRCL on PRM), with the addition of a +1 in the SRCL -> SRM element. For all 3 degrees of freedom (PRCL, MICH, SRCL), FMs 4 and 5 were always on. For PRCL, FMs 2,3,6 were triggered to come on after 0.5 seconds of delay. The PRCL FM triggers helped enormously. I tried several other things, including changing the MICH input matrix element up and down in value, changing the SRCL input matrix element up and down in value, and engaging triggering for a few different filters in the MICH and SRCL degrees of freedom. However, none of these made things better, and several made things worse. Most notably, for SRCL, engaging triggering for FMs 2 and 3 kicked the cavities out of lock, which implies that perhaps our gain isn't high enough yet (and thus our UGF isn't very high yet). I changed FM1 of SRCL to be +3dB of gain (from +10dB), and it would live through that coming on (trigger delayed by 1 sec, then ramping up over 1 second), but within a second after the filter finishing coming on, the cavity would fall out of lock (not violently kicked, just not locked anymore).
At this point, we were trying to figure out a way to confirm what kind of lock we had. I checked Optickle again, and we do not expect to see a significant change in POP110I between the PRMI and DRMI cases, so that isn't a useful check. We dreamed of having our AS110 demod board, or the AS OSA set up, but neither of those was going to happen tonight. Instead, Koji suggested hooking up the PD, and looking directly at the output.
To-do: Set up the AS OSA. Also, perhaps temporarily borrow the 110 demod board from POP. We were triggering on POP22 tonight, and that seemed to work okay.
Very nice!! I was wondering, shouldn't the driving matrix be such that MICH pushes on SRM as well?
Wonderful ! I like the video -- the spatial mode looks pretty clean and much cleaner than what I observed in the old days.
Hmmm, yes, that's a very good point. I think you're right, and I'll give that a try today.
Don't go for a hacky solution. We want to climb a staircase step by step.
Prepare an independent 110MHz demod ports.
To-do: Set up the AS OSA. Also, perhaps temporarily borrow the 110 demod board from POP. We were triggering on POP22 tonight, and that seemed to work okay.
The Y arm green transmission has been measuring in counts all along. I modified the gain in the ALS-TRY filter module to normalise the transmission.
Transmission has been normalised with GTRY = 1 corresponding to 600 counts.
Meh. 600 counts is too weak. You should fix the electronics so that the maximized green laser transmission gives more like ~10000 counts.
We were meditating a little bit on what may be the story behind the PRM violin filter situation. We locked the PRMI, and turned on and off the violin filters. We noticed, very bizarrely, that when the violin filters were ON, the servos would oscillate. Weird. Also, probably because the oscillation was causing us to hit the limit we have in the MICH servo, we rung up a 3rd harmonic of one of the violin modes, which was at 1955 Hz.
We took a transfer function of the PRCL servo, saw that the UGF was 300 Hz, and lowered it to ~180 Hz. After later investigations, that high-ish UGF probably wasn't a problem. Anyhow, we then took MICH servo transfer functions, and saw some very weird stuff.
At frequencies where we had violin filter notches, we were seeing peaks in the transfer function, which came close to touching, or crossed the 0dB line! We suspect that this may have something to do with the balancing of the drives to the optics, since we have PRCL driving PRM, but MICH driving BS and PRM. What we did was move the violin filter notches into the LSC model. There were already SUS filter banks in the LSC model (right side of the LSC screen). In preparation for the DRMI, I have put the BS violin notches into the BS, PRM and SRM filter banks, as well as the PRM and SRM filters into all 3 banks. Right now for PRMI, I have the BS and PRM notches (as well as the Vio3 notch) turned on in both BS and PRM. All of the violin-related filters are turned off in the LSC filter bank inside the SUS models. When we did this, the servo oscillations no longer are excited when we turn on the notches, and when we take a new transfer function, there are no longer weird peaks at the notch frequencies. More meditation needs to be done.
Also, for the violin3 filter, Rana noted that at 1955 Hz, after we confirmed that the REFL 55 phase was set correctly (and we're using REFL 55 I&Q for PRMI locking), the I-phase had a response of 0.36, while the Q-phase had a response of 0.20. I should be able to think about these numbers, and decide if the vio3 is for the BS or the PRM violin mode.
the above series of Bode plots shows the MICH Open Loop Gain as the REFL55 phase is adjusted (PURPLE, ORANGE) with the notches in the SUS and then (RED) as the notches are moved to the LSC and made the same for all optics.
In other news, I have the parts that Jamie ordered to make a new 110 demod board, so that's one of my daytime activities now, so we can have both POP110 and AS110.
Just to rephrase somewhat:
Friday night locking
Much more stable DRMI lock was achieved, partly thanks to the Friday-night quiet seismic,
and partly because of the improved servo gain and LF boosts
I wanted to confirm the enhancement of the 110MHz signal at the AS port.
As the AS110 PD is placed in the CCD path, there is nothing visible with PRMI.
The Thorlabs PD was moved to the main AS path. Now the AS110 PD is receiving 50% of the power.
With PRMI 110MHz peak was -30dBm (As it was fluctuating, anything more precise number did not make sense)
When the DRMI was locked, the peak was enhanced to 0dBm.
The 2f signal comes from the beat between the sidebands.
Thus the amplitude of the intensity is proportional to the power of the sidebands (assuming the +1 and -1 order sidebands have the same amplitude)
-30dBm -> 0dBm means 31.6 times amplitude of the intensity. Therefore the amplitude transmission of the sidebands is 5.6 times more. (Is this true?)
According to the wiki, the AS port thru-put (i.e. power transmission) for the 55MHz sideband is 0.0026 and 0.43 for PRMI and DRMI respectively.
This corresponds to the amplitude difference of ~13. So we still have only half of the sidebands leaking out from the IFO. This could be attributed
to both the smaller PR gain and SR gain.
Same as the one Jenne used the other day. Later I engaged several additional triggers.
The following is the trigger setting I used
MICH: Delay 2 sec, FM1/FM2/FM3/FM6/FM7
PRCL: Delay 0.5 sec, FM2/FM3/FM6
SRCL: Delay 5 sec, FM1/FM2/FM3/FM6
SRCL FM1 was modified from +3dB to +6dB
Once lock is acquired, it lasts tens of minutes. (see the attached striptool chart.)
Even the lock is lost, it reacquires quickly.
The videos to show the lock acquisition and the in-lock stability are attached below.
The AS port beam is very round. It is not so shaky, but some yaw motion is visible.
The mode at the AS port is defined by the SRM, putting a QPD at the AS port would help to
stabilize the spot.
IFO state upon leaving
I left the 40m with the arms aligned, PRM and SRM slightly misaligned, and LSC setting is for the DRMI locking.
- AS110I/Q for triggering
- PRCL/MICH/SRCL normalization
- We should resurrect the IFO config scripts.
- Remove BS->SRCL actuation coupling
- Handing off to 3f signals (preparation for the full lock)
- Improve ALS stability
- SRM ASC: AS QPD for SRM control
Lock Acquisition Video
UL (REFL) / UR (POP)
LL (AS) / LR (PRM Face)
UL (REFL) / UR (POP)
LL (AS) / LR (PRM Face)
We can put our scripts for the MICH, PRMI, and DRMI into the IFO CONFIGURE screens for now and then it should be easy to get them into the Guardian once Jamie has the bugs worked out.
This screen can also be used to setup and start the dither alignment for each configuration (once we have one working for DRMI / SRM).
Also, now that the notches/bandstop filters for the violin modes have been move from the SUS into the LSC, we should fix the triggering to engage them a few seconds after the boosts.
I made scripts/LSC/LSCoffsets2.py which is the script to zero the dark offset of all the LSC PD. The list of PDs is same as the list in scripts/LSC/LSCoffsets. New script average all outputs of PDs parallelly, so we can zero the offsets much faster.
You can define the averaging time, and you can choose the channel for getting the dark offset from INMON or OUT16. You should know that if you use OUT16 channel, the effect of the unwhite filter is not taken into account.
Example usage (at scripts/LSC):
./LSCoffsets2.py -d 20 --out16
you can find the help by calling this script with option -h or --help
What do you mean???
What is the effect of the anti-whitening filter?
You should know that if you use OUT16 channel, the effect of the unwhite filter is not taken into account.
PRM and ITMY were found with their watchdogs shutdown this afternoon (cause unknown). I re-engaged them.
I had made changes to the c1als model a couple of weeks ago. I had removed all the beat_coarse channels that had existed from pre-phase tracker era.
Also, I forgot to elog about it then. This dawned on me only when I found that c1als isn't working the way it should right now.
I have made a measurement of the PRMI and the DRMI sensing matrices.
Keiko pointed out to me in an email a little while ago that I wasn't zeroing elements in the oscillator drive matrix after using them, so I was effectively driving all the degrees of freedom at once, which is why some of the recent sensing matrices looked a little bullshitty. Anyhow, I put in a few lines to zero that row of the LSC output matrix, so that we don't do that any more.
PRMI sensing matrix:
DRMI sensing matrix, first-ever measurement, after the optic flipping / recent locking success:
Note that we don't have any error bars in the DRMI case, since the IFO fell out of lock during the error bar measurements. So, we got the "real" data from the degrees of freedom, but not extra data for making error bars. Also, the MICH / SRCL coupling hasn't been balanced out in the output matrix yet, but since the notches are engaged in the degrees of freedom during this measurement, that shouldn't be a significant effect.
To get the DRMI sensing matrix measured, I added the SRM's actuator calibration to SensMatDefinitions.py (data from elog 5637). I also created a new file runDRMI_sens, to be the equivalent of runPRMI_sens. In the new runDRMI_sens, I reduced the actuation from the oscillator by a factor of 10. I had several attempts at higher oscillator amplitudes that kept kicking the IFO out of lock.
The DRMI was pretty good, but I wasn't getting ~10s of minutes like Koji was on Friday. I also wasn't able to engage all of the FM triggers that he was. The 10-30 Hz seismic BLRMS is a little higher than a usual night, but other than that, seismic looks pretty quiet.
My settings for the night:
LSC input matrix: +0.1*REFL55Q = MICH, -0.125*REFL11I = PRCL, +1.00*REFL55I = SRCL.
Filter settings: MICH, PRCL, SRCL all had FM4,5 always on. MICH had FM2,3 triggered. PRCL had FM2,3,6 triggered. SRCL had FM2 triggered. In particular, engaging FM 6 for MICH or SRCL made some loud low-ish frequency oscillation. Engaging anything other than FM2 for SRCL kicked the IFO out of lock.
Gains: MICH = -0.800, PRCL = +0.050, SRCL = -0.100
Triggering: All triggered on POP22I, upper = 50, lower = 10 (lower = 25 for SRCL).
FM trigger thresholds: MICH on = 35, off = 2, delay = 2 sec. PRCL on = 35, off = 2, delay = 0.5 seconds. SRCL on = 80, off = 25, delay = 5 sec.
Power normalization: None, for any degree of freedom.
LSC Output matrix: MICH = -0.267 for PRM, +0.50 for BS. PRCL = +1.0 for PRM. SRCL = +1.0 for SRM.
LSC SUS filters: BS, PRM, SRM all had FM1,2,3,6 engaged for the BS, PRM and SRM violin filters, as well as the 3rd order harmonic for one of them.
I tried locking the SRMI, so that I could do the same kind of actuator calibration that Koji did for the PRMI in elog 8816, but was unsuccessful. I checked optickle, and found that for REFL 55 I&Q locking, MICH and SRCL keep the same signs for SRMI as DRMI. Also, for both, the optical response is a factor of ~15 lower for SRMI than DRMI, so the gains should be higher by a factor of 15 for both MICH and SRCL. I think my big problem here is that I don't have anything to trigger on. There isn't any signal to speak of in the POP PDs, with the PRM misaligned. Hopefully we'll have AS110 shortly, and that will help.
I updated the IFO Configure restore scripts to our latest versions of locking. I have also tested them, and restoring the Michelson, PRMI and DRMI all seem to work. (MICH restores to locking with AS55Q. PRMI restores to locking with REFL165 I&Q. DRMI restores to the settings noted above in this entry.) The X and Y arm restores have been working, and I have been using them (semi-)regularly since I announced them in elog 8433 back in April. Still to-do though: Add PRCL ASC to the PRMI up script, and make the dither options work for at least the arms and PRM. (Just need to point the drop down menu options to the new ASS scripts.)
I figured out the problem with ALS from yesterday. While the model was just fine, the medm screens were not checked if they were reading the correct channel names.
The channel names of the ALS input matrix elements had changed when the coarse channels were deleted from the c1als model. So the error signals were not reaching the servo modules as expected. This is why I was not able to make sense as to what the ALS was doing.
All is fixed now and should be back to normal
svn status update. asx, als and ioo were found not committed. Not sure about who modified ioo last after Jenne.
//edit Manasa - edited the/ elog instead of replying //
We did lots of poking around with the DRMI tonight. I should elog more in the morning, but the most important points are:
Locking settings same as elog 9068, except PRCL gain changed to 0.035, and the FMs that are triggered. PRCL tonight had FM2,3,6 triggered. MICH had FM1,2,3,7 triggered. SRCL had FM1,2 triggered. Engaging the MICH boosts helped make things more quiet, so that some of the SRC boosts could be enabled. Still not as good of lock stretches as Koji got last Friday (elog 9060).
REFL55 and REFL11 were still saturating (only during acquisition), after the optical path changes I did last week (elog 9043). We reduced the REFL55 whitening slider from 15 dB to 6 dB (but forgot to compensate with digital gain), to keep the counts (as seen on DTT time series, binning off) to less than ~20,000 counts. REFL11 is still saturating, and we're not sure why, since it's slider gain is 0 dB. To be investigated.
I was prepping the ASS to be more conveniently put into a wrapper script, which could be called from the IFO Configure screen. This involved adding PRCL to the burt .req and .snap files, as well as modifying the scripts a little bit to include PRCL as an option. I ended up changing the script names from DITHER_Arm_ON.py and DITHER_Arm_OFF.py to DITHER_ASS_ON.py adn DITHER_ASS_OFF.py, since they are no longer restricted to being arms-only. You must still provide an argument to the script, to tell it which degree of freedom you want to activate. I also changed the save offsets scripts. The way they were, the X and Y arms just had separate hard-coded scripts, with no convenient way to incorporate PRCL. I merged them (including PRCL) into WRITE_ASS_OFFSETS.py, which you must now provide the DoF as an argument. I tested these new scripts on all 3 of the DoFs, and made changes to the ASS screen, so it now calls only the new scripts. It should now be easy to incorporate future ASS modifications.
Rana was in the middle of modifying the ASS model to include SRCL, and we also need to include MICH. The ASS model is not compile-ready, so don't compile it!! If you need to compile the ASS, please save what's there as a different name, and do an "svn up" to get the latest working version.
We suspected that there might be angular drive issues with the SRM (it was wiggling a lot). We checked the damping via step responses - all Qs were less than 10. Then we found that the INPUT button on the SRM PIT OL was OFF (why ???). After turning this back on it behaved better. We measured the loop shape and found that the UGF was 7 Hz; good. Need to work on some loop shaping for this guy. Its just 1/f out to 300 Hz right now. UGF should be made a little lower so that we can stably turn on the Bounce/Roll notches and a ~50 Hz low pass filter.
Most importantly, the F2A filters need to be measured and implemented. They are a few years old.
I am responsible for missed svn commits with als and asx. I have committed them.
But I have not modified anything with ioo in the last few weeks.
Although Matlab 2013 has not been causing any visible trouble so far, it takes a while to startup.
I have added alias 'ml10' to bash to start Matlab 2010 from the terminal for convenience.
[From yesterday] ASS for X arm was behaving slightly funny over the last couple of days. ASS could not correct the BS misalignment. Jenne pointed out that the LSC output matrix on the ASS medm screen set itself to zeroes whenever we ran the ASS_dither_ON script. I checked the burt request file: ASS_DITHER_ON.req in /opt/rtcds/caltech/c1/scripts/ASS and found that the LSC output matrix channels were not added to it. I added these channels for both the X and Y arm. Following this, I also edited the corresponding snap file as well. This should now set the LSC matrix to the right values everytime we run the script.
I wanted to measure the OLTF of MICH.
What I did:
1. Ran LSC offsets script to zero all the offsets.
2. Restored the IFO configure settings for locking Michelson (locked on AS55Q).
3. MICH wouldn't lock on these settings.
4. The MICH servo was hitting its limits (10000 counts). I checked the filter module. After a little bit of looking into things, I disabled FM3 (0,0:5,5), FM4 (1:10) and FM7 (1:5). FM3 and FM7 were filter modules that were switched ON at the trigger. I set these to manual. Enabling any of the filters (FM3, FM4, FM7) caused MICH to lose lock.
5. MICH gain was changed from -20 to -30. MICH locked with ASDC suppressed to 0.01 counts. I looked at the power spectrum of C1:LSC-MICH_OUT on dtt. //edit: Manasa// The plot (uncalibrated) now shows MICH_OUT power spectrum with MICH PSL shutter closed, free-running MICH and loop-enabled MICH.
6. I then wanted to measure the OLTF of MICH using dtt. A channels were set to C1:LSC-MICH_IN1/C1:LSC-MICH_IN2 and excitation given through C1:LSC-MICH_EXC. But I have not been able to get any good coherence for the measurement as yet.
Beam trap for Pd refl is in place. Cabeling is ti·died up.
The extra high post 3.375" for PZT is ready. We also have 2 more 2" green Laseroptik mirrors. I'm ready to swap them in.
The 75 mm focal length lens was placed in front of the green REFL PD yesterday.
1, Vacuum envelope grounds must be connected all times! After door removal reconnect both cables immediately.
2, The crane folding had a new issue of getting cut as picture shows.
3, Too much oplev light is scattered. This picture was taken just before we put on the heavy door.
4, We were unprepared to hold the smaller side chamber door 29" od of the IOC
5, Silicon bronze 1/2-13 nuts for chamber doors will be replaced. They are not smooth turning.
Fred Goldbar of KoneCranes will come 7:30am Wednesday, September 4 to look at this issue.
It is changed to Thursday morning.
Valve configuration: Vacuum Normal
Rana asked me to look at the SUS MEDM screen upgrade situation, and provide an upgrade prescription. Unfortunately there not really a simple prescription that can be used, since our configuration diverges quite a bit from what's at the sites. But here's what I can say:
It looks like we already have the beginnings of an upgrade in place, so I say we just run with that. The new screens are in:
The primary screen is:
This seems to be a copy of the site ASC_TIPTILT screens. (In fact I think I remember putting this here). I went ahead and did some ground work to make it easier to get these new screens into place.
At this point someone needs to just go through and fix all the channel names to match ours, and tweak the screen to our needs (there's no side OSEM, for instance). The subscreens need to be cleaned up as well.
If there is a specific string you want to replace every instance of in the screen, you can do that easily from the command line like this:
sed -i 's/OLD/NEW/g'
This will replace every instance of the string OLD with the string new in the file path/to/file. Be careful: this will replace EVERY instance of OLD. If OLD matches things you don't want, they will be replaced as well.
This construction is actually "regular expressions", so if you want to get fancy you can match against more complicated strings. But just be careful.
If you leave out the "-i" the string-replaced text will go to stdout, instead of being replaced in the file "in place", so you can check it first.
If you want more fine-grained control of text replace, so that you can see what's being replaced, try using "query-replace" in emacs:
You can then type in the original string, followed by the replacement string. When it starts to run it will highlight the string that will be replaced. Hit "space" to accept or "n" to skip and go to the next.
We had fire alarm tests and evacuation drills at 1:30pm yesterday. All flashers and horns are functioning unbearably loud and bright including clean assembly room.
There has been a series of earthquakes since the big 7.0 in Alaska this morning.
None of the watchdogs were tripped when I came in. But I could not retrieve any info about the suspensions from fast channels because c1sus was not talking to the fb and that required an mxstream restart to fix it.
MC is trying to lock itself, but the seismic doesn't seem to get quiet. So MC is not all that happy.
I cleaned up around MC2 and 1Y1 area this morning.
ETMY NPRO moved from the side to the center of the low shelf. Thorlab catalog " as spacer " removed after lunch.
The Lightwave Controller values: LT 40.4C, LTEC +0.1V, T 41.041C, Pwr 239 mW, Adj 0, DC 1.82A, DPM 0.0V, Neon OFF, Ldon OFF, Display 5, DT 21.0C, Dtec +1.0V
The PMC was locked on an LG 10 mode (or something like it), for at least the last 8 hours. I relocked it on the regular 00 mode, and it's fine now.
Also, in CDS news, I did an mxstream restart (the RCG upgrade is supposed to make this not an issue anymore...), and did a "diag reset" afterwards, and all of the IPC errors except for one in the LSC model have gone away (OAF is still not running....on my to-do list, but not super high priority).
I have pulled the RF distribution box out of the rack, so I can look at it, and modify it to have 2 110 MHz spigots. I'm going to make the mods as in elog 9072.
Before I pulled the distribution box, I turned off the RF Generation Box, so don't be surprised that the MC will not lock. I have terminated the cables that bring the 11 and 55 MHz signals from the generation box to the distribution box, so if someone does turn on the generation box, there won't be bad reflections.
To get the box out, in addition to unplugging all of the cables that go to the distribution box, I had to disconnect 2 of the ADC ribbon cables from the top row of RFPD demod / whitening / ADC boards, since they were in the way. Everything is labeled, so it should be easy to put back together.
Note to Future Jenne: Past Jenne put the screws needed for those ADC cables and to hold the box in the rack, in the plastic box that is on the floor in front of the LSC rack.
Also, I measured the 110 MHz port before I pulled the board, so I would know what my "before" looked like. I was using the 300MHz 'scope's measurement functions, so these are in volts, not dBm. Amplitude = 1.33V, RMS = 456 mV, freq = 109.4-111.9 MHz
After scrounging for parts, and opening up the box, I have modified my proposal to the following:
Note that the freq multiplier is supposed to take, at maximum, 15 dBm. The reason I put the 5 dB attenuator, then an amplifier, then another attenuator is that I don't know of / can't find easily a 10 dB amplifier with the usual case type on the MiniCircuits site. (If anyone knows of one off the top of their head, that would be handy. Then I'd remove the attenuator between the multiplier and the amplifier, and make the 10 dB attenuator a 5 dB.)
Anyhow, the ZFL-500HLN can only output 16 dBm of power, and I don't think I have space for another ZHL-2 (which can output up to 26 dBm) inside the box, so I put an attenuator before, as well as after, the amplifier.
I think I have space inside the box for all the bits and pieces I'll need, although to do things correctly, I need to drill holes in the teflon mounting plate to mount the amplifier and splitter.
I also think that I have space on the front panel to put another isolated SMA feedthrough.
I have, on my desk, all the parts (except for mounting screws, and cables between things) to make these modifications to the distribution box.
~Vancuver, Canada earthquakes: magnitude 6, 5 and more shaking
The RF distribution box is still on the bench, so again, don't be surprised that the MC doesn't lock.
I have completed my modifications as proposed in elog 9096, but I want to do a couple of quickie tests in the morning before I declare it ready for service.
I have reinstalled the RF distribution box, as well put in the AS110 demod board. I plugged everything back in, and turned it all on.
The switch on the distribution box may be starting to fail. When I was turning the box on, I could depress the button, and see the blue glow, but it wouldn't catch, so when I removed my finger, the glow went away. I was afraid that I'd have to pull the box, but after a few more button toggles, I got it to stay on. I'm leaving it for now, but we should remember that this may be a problem.
I will look at the phases of all the PDs, but none should need changing except POP 110. Every other PD has the exact same cables as before.
While we were trying to relock the MC after Jenne put back the RF box, we found there was some mysterious motion in MC2. After spending time trying to figure out where this was coming from, the source was found to be at LOCKIN2 of MC2 suspension "The MC TICKLER" that was left enabled. This was turned OFF and MC locked just fine after that.
EDIT JCD: The Tickler should be disabled, if the autolocker is disabled.
I checked the demod phases for AS55, POP110, and all the REFL PDs.
AS55: I locked MICH, and shook the ITMs (+1 for Y, -1 for X), and watched the AS55 I & Q spectra at 580Hz (notch in the servo was enabled). I rotated the phase from -32.0 to +13.0 to get the signal entirely in the Q phase.
POP110: I locked the PRMI (triggering on POP22), and maximized POP22. I then rotated the phase of POP110 until the signal was maximally positive. I forgot what the starting phase was, but it is now 84. The POP11_I signal was entirely negative when I started, so the new phase is about 180 from the old phase. I also checked by unlocking the cavity, and seeing that a large peak in POPDC corresponded to large negative dips in POP110_I and POP22_I.
REFL PDs: I locked the PRMI, and shook the PRM (notches in the servos were enabled for both MICH and PRCL). Maximized the peak in the I phase. REFL11 was fine, REFL33 was fine. REFL55 was changed from 120 to 45. REFL165 was changed from 106 to 96.
I restored the SRM on the IFO_ALIGN screen, but the saved value was almost 2 full integers off in yaw from actual DRMI resonances. It looks like it was saved when Rana and I were working late last week. We must have accidentally saved it when it was misaligned, since hysteresis can't do that much.
I want to check the phases for POX and POY with arm locking, just in case. Also need to set the AS110 phase (which is plugged into the AS11 channels - need to fix the channel names).
Sounds like this was just incidental, since the MC locked fine also with the tickler enabled for weeks.
The tickle is disabled by the down script, but there's no way to correctly handle all possible button pushes. If you want to disable the autolocker for some reason you should run mcdown before trying to lock. This will set up things with the correct settings.
To estimate in-loop MICH noise:
(a) Calibrate MICH_ERR:
1. Lock the arms for IR using POX11 and POY11.
2. Misalign the ETMs.
3. Obtain the average peak-to peak (bright to dark fringe) counts from the time series of AS55_Q_ERR. I measured this to be d = 6.358 counts.
4. This gives the calibration factor for AS55_Q_ERR [Calibration factor = 2*pi*d/1064/10^-9 = 3.7546x10^7 counts/m]
(b) In-loop MICH noise:
1. Lock MICH using AS55_Q.
2. Since LSC input matrix sets MICH_IN1 = 1* AS55_Q_ERR, the power spectrum measured using dtt and calibrated using the calibration factor from step 4 in (a) gives us the calibrated in-loop MICH noise.
The plot below shows the in-loop MICH noise and the dark noise (measured by closing the PSL shutter):
Compared with old measurements done by Keiko elog 6385 the noise levels are much better in the low frequency region below 100 Hz.
(No, no, no... this is not an apple-to-apple comparison: KA)
Temporary fix for the switch: give a bit of oil to the button
Permanent fix: buy better switches.
Isn't that backwards? Shouldn't the tickler be enabled by the down script, and disabled by the up script? Either way, the problem was that, after I acquired lock, the tickler was causing the transmitted power to fluctuate by ~20%, and often the MC would lose lock after a minute or so. Also, the WFS definitely couldn't be enabled by hand.
Anyhow, I'll try to keep in mind that this exists, so I'm not stymied by it again.
You're right - down turns it on. Still, the fact that the same tickle recently causes a problem and didn't make 20% power fluctuations until now tells me that its not that the tickle amplitude is too large. Whatever changed recently is the problem.