Reset of HEPI L4C Accumulated WD Counters for HAM2 10:48 am.
Stopped the slave replication process on h1conlog3. Ran mysqldump -u root -p h1conlog > h1conlog_dump_7oct2014.sql on h1conlog3. Started the slave replication process on h1conlog3. Took about 10 minutes or so. Tarred the backup file and moved it to: /ligo/lho/data/conlog/h1/backups/h1conlog_dump_7oct2014.sql.tgz The size is 356M. I also added Dave B. to be emailed the hourly list of frequently changing channels. However, he does not seem to be receiving them yet. When this gets sorted out I will close WP 4891.
Last week we were wondering about possible ITMX excess motions. I reploted the optical lever motion from last friday including the calibration correction factors that Jeff posted yesterday. The first figure is the initial plot. The second one includes the correction.
While ITMX still show a large half-hour notion, the RMS values of the ITMs tends to be very similar dowm to 10 mHZ. In this measurement, the RMS values were around 20 nRad rms, both for pitch and yaw.
model restarts logged for Mon 06/Oct/2014
2014_10_06 01:32 h1fw1
2014_10_06 11:44 h1fw0
unexpected fw restarts
Weekly trend figures.
PeterK RickS We are about to go out to the Laser Area Enclosure early today to swap out the suspect AOM in the FSS optical path to the reference cavity, peak up the alignment, lock down mounts, etc. in an effort to reduce the alignment drifts we have been observing almost since the system was installed (see work permit).
I have had a difficulty transitioning the SRCL signal from the 1f to 3f signal. Not solved yet.
After playing with ALS DIFF, I went through the initial alignment process and then moved onto the DRMI. As tested before (alog 14283), the 1f locking with REFLAIR was fine with a laser power of 10 W incident on IMC. However I kept failing in the transition from the 1f to 3f signals tonight. It was due to the SRCL loop which did not like the 3f signal tonight for unknown reason. The PRCL and MICH loops could be transitioned to RF27_I and RF135_Q respectively without a problem. But SRCL seemed to saturate the M2 stage DAC every time (??) when I tried to engaged RF135_I. I tried adjusting the demod phase, but did not seem to help. Also checked the optical gain by exciting SRCL and confirmed that the input element of -2 which was taken care by the guardian is right. Also tried it with two whitening stages on in REFL135, but this did not help either.
Note that the build up of the sideband power looked high tonight:
Also, I had the modified L2P decoupling filter engaged on the M2 stage of SRM (see alog 14304) all the time tonight.
Here is a lockloss science. Not clear what exactly was going on.
I looked at three different lock loss events from yesterday. All of them were associated with very large saturation in the M2 stage of SRM which seemed to trigger instability in SRCL and destroy all the LSC loops eventually within a 2 sec or so.
The attached plot is the one from Oct-07-2014 09:24:22 UTC. In this example, PRCL and MICH had been already controlled by the 3f signals (i.e. RF27_I and RF135_Q respectively). In the middle of the plot, the SRCL 3f signal was ramped up (though it actually ramps down because of the control sign. The 1f signal was ramping down at the same time which is not shown in the plot.) Apparently the SRM M2 stage saturated quite hard. Following the M2 stage, the SRM M3 stage hit the DAC range as well. The BS and PRM M2 stages did not saturate until the loops became completely broken. An oscillatory behavior was seen in all three length signals and it was roughly at 13 Hz. Hmmm...
Alexa, Sheila, Kiwamu
we were able to lock ALS diff somewhat stably tonight, with a ugf around 5.5 Hz.
(free-swinging and in-loop spectra)
After playing with some gain settings and enabling LSC filters, I became able to robustly close the loop with a UGF of 10-ish Hz. I ended up with a L3_LOCK_GAIN of 1 for both ETMX and ETMY. In order to avoid DAC saturation I intentionally decreased the input element to 0.8. This seemed to help reducing DAC saturation events. I edited ALS_DIFF guardian accordingly. The attached below is ALS DIFF spectra of tonight:
(Red): in-loop spectrum, calibrated in um. (Blue): (almost) free-swing spectrum, calibrated in um. The blue curve was measured by conrolling ALS DIFF with an extremely low UGF. The in-loop RMS was about 600 pm which is almost the same as what we had in the HIFO-XY time (see for example, alog 11878). However, we are having 0.5-ish Hz feature in the in-loop spectrum which maybe due to some kind of angular coupling. I have not investigated this yet. Anyway, we are essentially back to the HIFO-XY performance.
(Out-of-loop measurements)
I was able to let the Y arm be on top of a resonance. A DARM offset that I found good was -0.0651.
Short term stability:
Please look at the red-ish and cyan curves which are IR_TRX and TRY respectively when the arms were held by ALS comm and diff.
Long term stability:
Things drifted on a time scale of 5-10 min. Also I noticed that the IR alignment in Y arm was not optimum. It should be roughly twice higher than it have been. Also, ETMY L2P was obviously worse than ETMX. Maybe the green alignment in the Y arm was simply not good ?
This lock strech can be found between 22:50 and 23:12 in PDT.
J. Kissel Following a similar procedure as was done for the ITMs (see LHO aLOG 14265), I've refined the calibration for the H1 SUS BS optical lever. The new calibrations are BS P 6.9522 [ct/urad] BS Y 3.8899 [ct/urad] They've not yet been installed; will install tomorrow during maintenance. DETAILS ------------ Currently, the alignment slider calibration gains are 4.714 [ct/"urad"] 4.268 [ct/"urad"] based on dead-reckoned knowledge of the actuation chain (see LLO aLOG 5362). Sheila and Alexa recently found the alignment values for the beam splitter which gets red light onto the ETMY baffle PDs: P ["urad"] Y ["urad"] ETMY PD1 184.0 -255.0 ETMY PD4 237.1 -287.7 or a displacement of BS P 53.12 * 2 = 106.2 ["urad"] BS Y 23.70 * 2 = 65.4 ["urad"] where the factor of two comes from the single bounce optical lever effect. I spoke with Gerardo who informed me that the numbers Keita had posted (LHO aLOG 9087) for the locations of the baffle PDs on the Arm Cavity Baffles are slightly off from reality. He gave me links to D1200296 (ETM) and D1200313 (ITM), which indicate that the PD locations are identical between an ITM and ETM baffle, and are 11.329 [inches] = 0.288 [m] apart in vertical, and 11.313 [inches] = 0.287 [m] apart in horizontal. Again using 3994.5 [m] for the length of the arm (LHO aLOG 11611), and adding 4.847+0.100+0.020+0.200 = 5.167 [m] for the distance between the HR surface of the BS and the back of the CP, through the thin CP, through the ITM QUAD's reaction-to-main chain gap, and through to the HR surface of ITM, respectively (D0901920), that's a lever arm of 3999.7 [m]. Hence, a displacement of BS P 0.288 [m] / 3999.7 [m] = 72.01 [urad] BS Y 0.287 [m] / 3999.7 [m] = 71.76 [urad] The alignment offset slider gains should therefore be corrected by BS P 72.01 / 106.2 = 0.67806 [urad/"urad"] BS Y 71.76 / 65.4 = 1.0972 [urad/"urad"] or BS P 1.4748 ["urad"/urad] BS Y 0.91141 ["urad"/urad] The new slider gains should therefore be BS P 4.714 [ct/"urad"] * 1.4748 ["urad"/urad] = 6.9522 [ct/urad] BS Y 4.268 [ct/"urad"] * 0.9114 ["urad"/urad] = 3.8899 [ct/urad] We're now storing 4 alignments for the BS, P ["urad"] Y ["urad"] BS Aligned 210.6 -271.4 Misaligned 236.5 -287 To EY ACB PD1 184 -255 To EY ACB PD4 237.1 -287.7 which should therefore become, P [urad] Y [urad] BS Aligned 142.8 -297.3 Misaligned 160.3 -314.9 To EY ACB PD1 124.76 160.77 To EY ACB PD2 160.7 315.66 To do: - Update calibration in OPTICALIGN gain - Update calibration in M1 LOCK bank - Update, confirm, and save corrected alignments - Capture new safe.snap
OPTICALIGN Calibration gains have been changed, but only the ALIGNED and MISALIGNED values have been stored. Still need store PD1 and PD4 values, commit the snaps to the userapps repo, and capture a new safe.snap. Turns out there are NO calibration filters in the H1SUSBS M1 or M2 LOCK filter banks yet, so they need not get updated. Will do what I can tomorrow.
Completed OPTICALIGN alignment offset slider calibration refinement this morning: saved ALIGNED_TO_PD1 and ALIGNED_TO_PD4 values, confirming that they're hitting the ITMY baffle PDs. Finally, captured a new safe.snap. Now moving on to optical lever calibration refinement using new values.
K. Venkateswara
This week, I will be installing and testing the "damping turn-table" to actively damp the beam-balance in the BRS whenever it gets driven to large amplitudes.
BRS had stopped working a few days back, so I took a look at the BRS-DAQ laptop today. Just as before 13817 the CCD had temporarily stopped working causing the program to freeze up. Still not clear on why this happens but it looks like the crashes are irregular.
After restarting the program on the laptop, I noticed that the main-mirror pattern had barely drifted off the CCD (it was missing one peak out of 38). To correct this I adjusted the left-right center of mass (COM) of the balance using the small flexible adjuster located in the front face of BRS. The correction was an iterative process and took about 30-45 mins. For future reference, moving the moveable rod (located on the balance) towards the right (or south) shifts the center of the pattern to the right and vice versa.
After damping the balance and turning on the program, I noticed that there was some excess noise visible in the output going to the CDS which seemed to be due to the lack of an anti-aliasing low pass filter in the code. I had bypassed the low-pass filter to save computation cost, but apparently there is more high-frequency noise in the CCD output than before. After enabling the anti-aliasing filter, the output going to CDS looked clean again.
Over the next few days Jeff and I'll also try to resume where he left off here: 14047. I've attached a pdf showing the BRS, GND_STS and ST1_T240 measurements for comparison. This data set was measured this afternoon starting at: 1096665586. ST1 motion is smaller now in 10-100 mHz band after improvements to the configurations over the last several weeks, but there is still a lot of coherence with the GND sensor.
(Keita Daniel)
We are setting up the feedback paths for the EY WFS servos. Simple 1/s filters are currently loaded into DOF_3 and DOF_4.
We noticed that the IPCs for feeding back to the test masses were set up in the ISCEY model, but that they were only connected for EX in the ASC model. The ASC model was changed on disk but no yet committed.
The cameras with the green filters blocking the 1064nm wavelength are working on the ITMs. Exposure set to 30,000. The images look rather different between X and Y, so.
Added additional offsets and normalization capabilities to the camera position code in the ISC end station models. Needs to be loaded. A new medm screen was also added.
LVEA is Laser Hazard 09:15 Ken – Finished installing power receptacles in LVEA. Going to do same at the end stations. 09:39 Betsy & Travis – Working in LVEA west bay on 3IFO Quads 09:57 Kyle – At Ham6 to turn off rotating pumps and start Ion pumps 10:04 Krishner – Going to End-X to install BRS sensor turntable 10:10 Filiberto – Recovering electrical equipment from the Ham2 area 11:50 Karen – Cleaning at End-Y. High dust counts (+10k range) and a lot of moths 13:20 Gerardo & Peter – Working on OFI optical alignment in H2 PSL enclosure 13:20 Cris – Cleaning at End-X 14:38 Betsy – Working at SUS test stand LVEA west bay 15:28 BFI on site to pick up recycling at staging building
All four DOFs of green WFS servo was engaged with the WFS centering on and they didn't run away.
The servo doesn't necessarily maximize the green transmission. Both the stability as well as the operation point of the servo is strongly dependent on the beam position on WFS heads, so some more fiddling around is necessary.
Right now the servo only acts on the PZT mirrors on the ISCTEY, yet the servo is very slow as the YAW WFSA and B look degenerate.
Trying a small modification to the ITMY blends tonight. Because the Z/RZ is suspected to be caused by actuator drive currents, Sheila has allowed me to switch the Z on St1 to a higher blend. If this proves unworkable for arm work tonight, the blend can be switched back easily enough to Tbetter on Z. Getting Ryan's 90mhz blend is possible, but right now would require turning off the Z isolation loop, a bunch of extra clicks( switch each of the individual current blends), then turning the loop back on.
I'm attaching some data that prompted the change. Fabrice made a script last week that plots the coherence of the ISI St1 T240's to the Oplev signals. I messed with it this morning a little to look at all degrees of freedom, shown in the attached plots. The first 2 pages show ISI to oplev pitch, the last 2 are ISI to oplev yaw, from Sunday night, with ITMY in our new <a href="https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=14284">"standard configuration"</a>. Basically, red means high coherence, meaning the ISI is strongly coupled to the motion the oplev is seeing, or something. We think that Z isolation is not strongly coupled to optic motion, so reducing isolation there won't negatively affect the optic. But, reducing the amount of drive on Z, I hope, will reduce the amount of RZ/yaw that is induced.
Plots from ITMY last night with high blend on Z.
Sheila, Alexa
We aligned TMSX again using the baffle PDs. We noticed this gave a slightly different alighment than the 'TMSX Align' script.
| Old Script | PD1 | PD4 | Average | |
| TMS (P,Y) | (19.9,-324.8) | (-58.2, -295.9) | (9.8,-358.9) | (-24.2,-327.4) |
The TMSX guardian now has a 'PD1 Aligned' and 'PD4 Aligned' states that are currently saved to the value listed above. We have also updated the centering on the GigE camera so that the script is consistent with above centering and no longer has such a discrepancy.
| Old Center | New Center | |
| GigE (X,Y) | (383.4, 261.6)) | (391, 267) |
We have proceeded to lock IR to the x-arm using the ALS COMM handoff. Last week, we had noticed that the COMM VCO would rail if we enabled the servo, and would manually set the frequency by adjusting the tune offset. Today we noticed that the frequency monitor was sometimes giving bogus values. We checked that this was not coming from the timing comparator. Reconnecting the output of the COMM FDD seemed to have fixed the problem. Now we can enable the COMM VCO servo to search for the IR. The IR frequency offset had to be adjusted to 21620Hz (or -15930 Hz). Now, the guardian script 'IR_FOUND" successfully finds the IR resonance in the x-arm.
PSL Status: SysStat: All Green, except VB program offline Output power: 33.6w Frontend Watch: Green HPO Watch: Red PMC: Locked: 3 days, 4 hours, 37 minutes Reflected power: 1.9w Power Transmitted: 24.0w Total Power: 26.0w FSS: Locked: 0 days, 0 hours, 6 minutes Trans PD: 0.586v ISS: Diffracted power: 8.103% Last saturation event: 1 days, 20 hours, 47 minutes
Unless someone is running a configuration test, this state is not nominal and should be corrected. Usually, we can switch this with out too much stirring up of the platform.
switched to hi gain ~0730pdt Tuesday.
In a previous alog entry I pointed out that most of the intensity nosie we see in transmission of the IMC is due to input beam jitter converted to RIN due to an IMC misalignment. Today, to prove this, I improved the IMC alignment in three steps:
The third attached plot shows the improvement in RIN in transmission of the IMC. Now it is at a level of 1e-6 at 10 Hz and 2e-7 at 100 Hz. It's almost a factor 10 better everywhere.
It's interesting to note that the RIN is still non stationary, so we should improve further the IMC alignment accuracy. I could not increase more the gains of DOF1 and DOF2, since I got a 1 Hz instability (as expected from the open loop transfer function). However, my intuition is that the IMC mirrors are pretty much not moving, and instead the input beam pointing is moving a lot. So we should servo the input beam to the IMC cavity axis with some Hz of bandwidth. This is what we did at Livingston, where the input beam motion was limited by air currents in the PSL room. I believe a similar approach should be used here. This is much better than high bandwitdh loops on the mirrors, since they should be our best reference.
To study the dependency of RIN on IMC angular fluctuation I used a code developed for a similar task at Livingston. See more details here. In brief, i compute the band-limited RMS of the IM4_TRANS_SUM signal between 50 and 10 Hz, and correlate this with the low frequency content of the IMC alignment error signals. The scatter plot in the 4th attachment shows the correlation between each IMC angular DOF and the BLRMS. There is a clear correlation with DOF1_Y. From the scatter plot we can also see that there is an offset on the error signal.
A more quantitative analysis can be obtained by fitting the BLRMS time series with a linear combination of a constant, the error signals and their squared values. The procedure I used is a slightly modified version of a LSQ fit, and it gives me a ranking of the signals as a function of their importance in improving the fit. The code is attached to this entry. Basically, the first step is to find which one of the channels (constant, error signals or their squares) can be best fit to the BLRMS. finding the minimum residual squared error. Typically a constant is the first winner. Then the procedure is repeated with the residual, looking for the single bets channel to furher reduce the rfit error. At each step I search for the channel that reduces the error the most. The procedure is repeated iteratively.
The 5th plot shows the result of the fit before any improvement on the IMC alignment. Most of the noise fluctuations could be explained by angular motions. The 6th plot shows the ranking of the channels (the bigger the bar, the most important the channel is), confirming that DOF_1_Y is our best candidate.
The 7th plot shows the measured open loop transfer function of IMC DOF 1 Y before and after my gain increase. The loop had a bandwidth of probably 3 mHz with the original gain of -1. The plot shows the OLTF with a gain of -100, giving a badwidth of 300 mHz. I did not measure the other DOF1 and DOF2 loops, but I could increase their gain in a similar fashion.
After some tweaking, I reduced the gains to -20, since the error signals were showing a large 1 Hz instability, which is consistent with the measure OLTF. However, we are clearly still limited by the residual motion of the beam with respect to the cavity axis.
I'm leaving this configuration running, as shown in the attached screenshot. In case there is any problem, revert back to the original configuration by reducing the gains to -1 and removing the two offsets. No other modification will be needed.
Since I don't like much the idea of running WFS loops with offstes, I tried to zero them by moving the beam on the WFS using the picomotors, but I couldn't get any effect at all, no matter how big step I was moving.
To clarify, all the measured RIN reported here is without engaging the ISS second loop.
