J. Kissel

Since updates to the CAL-CS model have been a little sporadic over the past few days, I recap below what happened when, as logged by the filter archive.
What Changed                                                                    Local Time (PDT)    Corresponding Archive of Change    Corresponding aLOG

SUS dynamical model update is complete                                          Thu Sep 10 13:50    H1CALCS_1125953445.txt             LHO aLOG 21322

Cavity pole frequency changed from 389 to 341 [Hz] (+optical gain name change)  Thu Sep 10 14:03    H1CALCS_1125954209.txt
Optical gain is renamed (no substantial change)                                 Thu Sep 10 14:03    H1CALCS_1125954234.txt   
DARM_ERR Optical gain is tuned                                                  Thu Sep 10 17:49    H1CALCS_1125967809.txt             LHO aLOG 21385

Installed inverse actuation filter                                              Sun Sep 13 22:35    H1CALCS_1126244167.txt             LHO aLOG 21487

Kiwamu changes L1 and L2 violin modes                                           Mon Sep 14 09:03    H1CALCS_1126281835.txt             LHO aLOG 21500

Copied new inverse actuation filter over to blind injection                     Mon Sep 14 09:08    H1CALCS_1126282148.txt             
Changed the names of the blind injection filter banks (no substantial change)   Mon Sep 14 09:09    H1CALCS_1126282176.txt             LHO aLOG 21499
(Note the filter files are tagged with the GPS time that they're created. so they're more accurate (to the second) than the local time I quote.)

Given that the DARM calibration was tuned at Sep 10 2015 17:49:00 PDT = Sep 11 2015 00:49:00 UTC, and Kiwamu started the PCAL to CAL-DELTAL_EXTERNAL transfer function at Sep 10 2015 18:08:12 PDT = Sep 11 2015 01:08:12 UTC, I would conlcude that 
the front-end calibration has been stable for LHO since the first lock stretch that was placed in observation mode after that measurement, which starts at 
     1125972087 = Sep 11 2015 02:01:10 UTC = Sep 10 2015 19:01:10 PDT
until the last observation stretch -- which ended at 
     1126281754 = Sep 14 2015 16:02:17 UTC = Sep 14 2015 09:02:17 PDT
-- before Kiwamu's change at Sep 14 2014 09:03:00 PDT = Sep 14 2015 16:03:00 UTC. 

I say the front end calibration has been "stable" instead of "valid" because because we know that Kiwamu's work this morning was to correct a systematic error from a bug that had been found.

We only briefly took the IFO out of observation mode (though the IFO stayed happily locked) while Kiwamu loaded new SUS filters and I the copy of inverse actuation filters. We resumed a new observation segment Sep 14 2015 16:10:43 UTC.

As noted in Kiwamu's most recent aLOG about updating the calibration this morning (LHO aLOG 21500), his update changed the UIM and PUM stages, and for features well-above the cross-over frequencies of those stages (TST/ PUM ~30-40 [Hz], PUM / UIM ~ 2 [Hz]). The update was a bug fix, and it means that the front is now more accurately representing the violin modes that were already correct in the DARM model. We all suspect this is a small change in the overall actuation function, but the recent discovery of how poorly the PUM has been rolled off (LHO aLOG 21419), means we have to verify. 

After these messages, we'll be riiiight back. *whistle glitch*

P.S. Since Matt and I performed all of our inverse actuation filter design on the original matlab model of the DARM actuation function, the inverse actuation filter design and implementation is unaffected by Kiwamu's change, nor was it impacted by the systematic error that he found.

Mike Landry & Vern Sandberg  ER8 to O1 Transition

Cancellation of Tuesday Maintenance Day, September 15, 2015 to allow for IFO ER8-Quality data collection.

• Title: 9/14 Day Shift: 15:00-23:00UTC all times posted in UTC

• State of H1: Observation Mode at 70Mpc for the last 8hrs

• Support: All the commissioners

• Shift Summary: Mostly quiet, but worsening range at the end 

• Activity Log:

• 15:30 Ken working at warehouse, hooking up wiring for fire suppression system
  16:00 ChrisS and JoeD working on arm, recalled at 18:20, 
  16:00 Kiwamu and JeffK working on calibration and hardware injections for a couple minutes
  16:15 Bubba and JohnW driving down Xarm to investigate an air compressor 250m from EX, done 17:20
  16:45 Hugh at EY
  16:45 Fil to CER, out at 16:55
  17:00 Hugh at EX, out at 17:10
  17:55 Hugh in Mechanical Room checking HEPI fluid levels
  ~22:20 Range starts getting ratty and DMT OMEGA scans on control room display shows we are getting glitchy, numerous ETMY saturations
   
   
   

Checked the Reservoir Levels this morning.  All steady; no further maintenance called for.

Attached are 60 day means of the HEPI Drive outputs.  The expectation is that if we have a bad valve, this would show in a trend up or step up as the valve is failing.

Not sure about the efficacy of this manner of investigation and this 60 day look could easily be too coarse to see the needed details plus it is confused with platform trips and maybe the occasional alignment change, but for now, it looks like there is no obviously bad or failing valve. I'll continue with weekly or bi weekly shortly duration trends.  We are attempting to avoid doing the invasive Valve Check routine.

From the tinj log files, and visible on https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20150914/plots/H1-ALL_893A96_ODC-1126224017-86400.png, I see that two scheduled burst injections were successful this morning.  The GPS times were 1126270500 and 1126280500.  That's good, because it seems to mean that yesterday's problem with injections was temporary.

These injections were only done at LHO; LLO was not observing at those times.

Beverly, Jess

• For this DQ shift, the duty factor over the 4 days was 33.0% with the range mostly around 75 Mps or so.
• 50 Hz glitches: An unexpected round 2 winner in Hveto was traced to 50 Hz glitches that were shown to be related to ground motion in EX (alog) and later correlated with the turning on of an air compressor located there (alog).
• Range drops: The ETMY "saturations" (apparently due to DAC crossings ( alog)) continue to be present causing range reductions. Possibly interesting is the time series in h(t) and ETMY for a glitch causing a small range drop (see Fig. 1). Throughout this DQ shift, there appeared to be no obvious noise associated with the range drops visible in the h(t) spectrograms in the Summary pages. However, a feature (at the frequencies of the bounce and roll modes) in the h(t) spectrogram for  the lock on 13 Sept was seen to coincide with a range loss (see Fig. 2).
• New lines visible: Lines at about 500 Hz (violin modes) and 2400 Hz (unknown) were seen in the early part of locks on 10 and 11 Sept. The 2400 Hz line did not appear on subsequent days.
• Feature associated with bad alignment: A feature seen in the early parts of locks on 10 and 11 Sept in the range of 300-350 Hz (see Fig. 3) are probably due to lines associated with the PSL Periscope. We consulted Paul Altin who believes that this feature was a precursor to increasing noise due to worsening alignment. This feature did not appear on 12-13 Sept.
• CBC glitching: CBC BBH Omegagrams showed several categories of glitches although this study is still in progress.

The full details for the shift may be found here. 

Bubba and I inspected the instrument air compressors at both end stations and the corner.

The two end stations have failed vibration isolators. Bubba is checking our inventory of spares.

The corner station is in good condition - and has been mounted in a different fashion.

Attached are two photos; shorted.jpg is one of the end station units, notshorted.jpg is the corner.

Ref; https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=21436

WP 5489

I have update the violin mode filters in CAL CS in order to make them more accurate. This will impact on the calibration at sub-percent level at around 30 Hz.

Joe B pointed me out that the way my matlab script (alog 21322) handles violin's zpk was not ideal (i.e. I was implicitly assuming certain ordering in the zeros and poles in zpk data format). I corrected the script as was already done in Livingston (LLO alog 20512). This resulted in somewhat better accuracy for PUM in 1-100 Hz . The attached screenshots are the new filters and discrepancy between the full ss model and the installed discrete filters. Compared with the one I previously reported in alog 21322, the magnitude of PUM is now somewhat better. The magnitude of PUM at 30 Hz is now more accurate with a very small discrepancy of 0.08 % (which used to be 0.2 % discrepancy ), and it is also more accurate at 100 Hz with a small discrepancy of 0.65 % (which used to be 2.4 %). I do not expect any noticeable change in the binary range with this update.

I have installed the new filters and loaded the coefficients in CAL-CS.

Bubba and John want to drive down the Xarm, so I've taken the IFO to commissioning/maintenance. Otherwise, no work is currently being done on the instrument.

• Title: 09/14 OWL Shift: 7:00-15:00UTC (00:00-8:00PDT), all times posted in UTC
  

• State of H1: Recently recovered from a lockloss due to a 4.7M earthquake in Oregon. Observing at 68 Mpc.
  

• Support:
  

• Shift Summary: Locked and observed most of the shift. The BNS range dropped from 73 Mpc down to 66 Mpc in ~5 hours. Only three ETMY saturations since shift started (not including the saturation caused by the earthquake).

• Incoming Operator: Jim

• Activity Log:

• 7:00 IFO locked. Intent bit commissioning. Jeff K. updating filters, Stefan and Evan working on calibration and OMC mode matching. Sorry I forgot the transition summary.

• 7:36 Intent bit set to Undisturbed.

• 7:49 Briefly went to commisioning to close the beam diverter before I realized it was already closed.

• 14:00 Lockloss due to 4.7M earthquake in Lakeview, Oregon. Only SUS OMC SW watch dog tripped.

• 14:28 Locked again at NOMINAL_LOW_NOISE. There's a tall peak around 18 Hz (another roll mode?). I watched to make sure it's being damped before setting intent bit to Undisturbed.

• 15:00 Handing off to Jim.

•  

•  

J. Kissel, M. Evans

After downloading the work that Matt has done (LHO aLOG 21424)carefully fitting the nasty actuation function we'd discovered (LHO aLOG 21419), 
1) I've plotted it myself, to make sure I understand what Matt has given me
2) Inverted it, made sure I got the same residuals he did
3) Discovered the fit contained a pole at 15 [kHz], played around with the implications of moving the pole to the highest frequency foton accepts (8190 [Hz])
4) Painstakingly copied over to foton, because the fit poles and zeros did not all fit into one filter bank, and *I* wanted to control how they were divided between banks
5) Exported the foton filter, loaded it back into matlab, and fine tuned the necessary advance.

T'was a lot of work, but we have something installed and running. Now we beat the heck out of it to find the bugs, while we (in parallel) push injection through the photon calibrator forward.

In addition to this pain-in-the-tuckus inversion process, Joe Betz -- on the phone for other reasons -- brought up another excellent point: LHO does NOT use linearization on the H1SUSETMY electrostatic drive. While we get away with doing so during a quiescent lock, any loud control signal will expose the non-linearity (quadratic) nature of the ESD. We think we've already seen some evidence of this while measuring DARM open loop gain transfer functions. Yuck. PCAL has no such problems (in fact, though it uses an inherently quadratic AOM, it has analog electronics to ensure its linearity).

Note: Contrary to all of my suggestions, Matt *has* included and fit inverses to the notches in the actuation function. This means, while we will likely have the same amplification problems around the notch frequencies (see, e.g. LHO aLOG 20904), the phase reconstruction of all regions except this frequency is within 5 [deg]. Since there seemed to be competing interests in the CBC group on whether or not to include the inverse of the notches, I've left them in. If we need to remove them, and somehow retain the phase reconstruction in the surrounding frequency regain, then it'll be another day's worth of work between Matt and I. But honestly, if it comes to that, we're switching to PCAL.

%%
Details
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Not much to say on the design here -- Matt did almost all of the work. The only two gotchas were as mentioned above: I had to move the highest fitted pole down and I must split the filter in to two parts. For the splitting, I chose to put everything from the (inverse) beam-splitter violin mode notch at ~300 [Hz] into the first module ("O1.A" in FM3), leaving the (inverse) QUAD violin notches and 950 [Hz] elliptic low-pass for the next ("O1.B" in FM4).

After exporting the product back into matlab, I tuned the timing advance to account for the pole that I'd moved down from the "ideal" fit. 
Thus, all analysis should assume the waveforms need a timing advance of 255 [us]. 
Also, of course exactly surrounding the frequencies of the notches at ~300, 500, 1000, and 1500 [Hz] there is greater than 50% mismatch between the real SUS and the inverse actuation filter. 

The first .pdf attachment shows 
(pg 1) my reproduction of Matt's filter comparsion (over a little bit wider a frequency band), 
(pg 2) the inverse function, both of Matt's ideal fit, and of the reconstruction from foton, and 
(pg 3) a zoom in on the interesting region between 100 [Hz] and 2000 [Hz].

The second .pdf attachement shows a bode plot showing the breakdown of the filter between FM3 and FM4, and compares the filter against the ER7 filter. 

Noteably, there is *not* a sign difference between the new filter and ER7 or the H1 Mini-run filter, but the phase has rotated once around the unit circle.  For a clear demonstration of this, see the third .pdf attachment. Recall, folks have been worried about the hardware injection filter since ER7 (see LHO aLOG 19948 for complete summary). I'm not sure how this ~360 [deg] rotation could be mistaken for a sign flip -- but maybe I'm just carrying around the term that was used during the initial guess of what the problem was, even though the real problem was more subtle. I've confirmed that neither the design string nor the "alternate" (i.e. as what foton interprets your design) show a minus sign in the gain.

--------
Configuration control:
(1) Stefan and I updated the ODC state vector for the hardware injections, since flipping the FMs from 2 to 3&4 make the "HARDWARE filter stated OK" light go red. To make green, we changed the recently modified bit status check from 0x1602 to 0x160c. 
(2) I accepted the new filter bank state (and ODC bit word) into both the OBSERVE.snap and into the SAFE.snap for the CAL-CS front-end model.
I attach ascreenshot of the filter bank as I've left it.

Things were quiet. Then Stefan arrived, and I realized I had set the observatory mode but forgot the Intent Bit, and which spiraled into a bunch SDF differences. The LSC guardian showed a difference on a t-ramp (annoying that this kind of difference would keep us from going into Observe) and ASC had two diffs that I guess Evan logged about last night but didn't accept. Then Stefan went and set a bunch of ODC masks (this also would have kept us from going into observe, so also annoying) as well as tuning the whitening the IM4 QPD (which was saturating, Stefan assures me is out of loop so shouldn't affect anything). Guardian recovered from the earlier lock loss in 20 minutes (not annoying!) back to 70 mpc and it has been otherwise quiet.

While we were in commisioing mode, we had a strange non stationary spectrum, with large non stationary noise also appearing in MICH and PRCL.  I quickly looked at some triple witness sensors, since we've had issues with these recently, but didn't see anything obvious.  

The strange noise started a few minutes before 2:50:34 UTC Sept 10, seemed to get better for a few minutes and then got worse again around 2:57:21. 

We don't think that this was related to any comissioning we were doing.  Evan had temporarily lowered the DARM ugf and put a notch in, (which should cause anything like this).  He undid both changes when we saw the unusual noise, but the noise was unaffected by his change.  

We aren't going to investigate any further right now since the problem seems to have gone away.  

Dan, Evan

This evening we made a qualitative study of the coupling of beam jitter before the IMC into DARM.  This is going to need more attention, but it looks like the quiescent noise level may be as high as 10% of the DARM noise floor around 200Hz.  While we don't yet understand the coupling mechanism, this might explain some of the excess noise between 100-200Hz in the latest noise budget.

We drove IMC-PZT with white noise in pitch, and then yaw.  The amplitude was chosen to raise the broadband noise measured by IMC-WFS_A_I_{PIT,YAW} to approximately 10x the quiescent noise floor.  This isn't a pure out-of-loop sensor, and since we were driving the control point of the DOF3 and DOF5 loops of the IMC alignment channels we will need to work out the loop suppression to get an idea of how much input beam motion was being generated.  Unfortunately we don't have a true out-of-loop sensor of alignment before the IMC.  We may try this test again with the loops off, or the gain reduced, or calibrate the motion using the IMC WFS dc channels with the IMC unlocked.  Recall that Keita has commissioned the DOF5 YAW loop to suppress the intensity noise around 300Hz.

The two attached plots show the coherence between the excitation channel (PIT or YAW) and various interferometer channels.  The coupling from YAW is much worse: at 200Hz, an excitation 10x larger than normal noise (we think) generates coherence around 0.6, so the quiescent level could generate a few percent of the DARM noise.  Looking at these plots has us pretty stumped.  How does input beam jitter couple into DARM?  If it's jitter --> intensity noise, why isn't it coherent with something like REFL_A_LF or POP_A_LF (not shown, but zero)? 

The third plot is a comparison of various channels with the excitation on (red) and off (blue).  Note the DCPD sum in the upper right corner.  Will have to think more about this after getting some slpee.