J. Kissel, J. Betzwieser

Patrick had called out that line features the DARM sensitivity around 35 Hz were "broadening and contracting" in a recent lock stretch starting 2017-03-29 11:10 UTC, which impacted the inspiral range (see LHO aLOG 35173). These features are the 35.9, 36.7, 37.3 Hz calibration lines actuated by the ETMY SUS, PCAL, and overall DARM_CTRL, respectively. 

What Patrick has seen is classic alignment-related up-conversion, where low-frequency (between 0.05-10 Hz) angular motion mixes with the intentionally, and necessarily loud calibration lines and creates side-bands on the CAL lines that mirror the ASD of angular motion. We've been anecdotally/casually/qaulitatively seeing this several times in the recent past.

This time, however, it seems to have gone so far as to pollute the calculation of the time-dependent correction factors, which are applied to the astrophysical output -- namely the relative ESD/TST stage actuation strength change ("kappa_TST"), and the relative optical gain change ("kappa_C"). Since the data were so noisy around these lines (the SNR dropped from the typical ~500 to less than 10), this dropped the coherence between excitation and DARM, and increased the uncertainty beyond our pre-defined thresholds for good data.

As such I recommend this data stretch to be flagged as garbage by DetChar, from where bits 13 & 15 ("kappa_TST median" and "kappa_PU median") of the H1:GDS-CALIB_STATE_VECTOR are red during this observational stretch.

I attach good deal of plots to help support the interrelated case between
    - The DELTAL_EXT sensitivity of the detector, zoomed in around both the 2150 Hz OMC dither lines and CAL lines 
    - OMC Dither Alignment Control (whose error signals are informed by 4, evenly spaced lines between 2125 and 2200 Hz)
    - OMC SUS and OM3 alignment
    - DHARD Pitch Control
    - The noisy kappa_TST and kappa_C 
and then other plots that show it's NOT causally related to 
    - Earthquakes (the recent EQ at 4:30 UTC was done by then)
    - ETMY Optical Lever Excursions (ETMY's optical lever went off into the weeds, but what's shown in the BLRMS is just the ring-down of the low-pass filter)
    - 1-30 Hz GND Motion (the increase happens *after* this alignment excursion)
    - Large differential motion of the ETMs (ETMX X and ETMY Y show that same ISI ST1 performance at 11:30 UTC and 03:00 UTC which are bad and good times, repectively)

I don't have any speculation as to which of the inter-related symptoms are the actual cause of the problem, and/or I don't have a clue as to why the OMC dither line heights are so much louder during the bad time. I'll ask around for speculation from other members of the commissioning team.

TITLE: 03/29 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: Patrick
CURRENT ENVIRONMENT:
    Wind: 11mph Gusts, 9mph 5min avg
    Primary useism: 0.21 μm/s
    Secondary useism: 0.38 μm/s
QUICK SUMMARY:

Site Activities:

• Richard and Fil are driving down X arm looking in the beam tube for equipment
• tumbleweed balers are working on X arm, started about 1/2 way between Mid-X and EX, and are working their way toward the corner station

H1 Activities:

• H1 was locked and heading to NLN when I arrived
• it made it to NLN, and then had a lock loss due to an earthquake
• Hugh is working on ETMY BRS - preliminary go ahead to use if needed, but he's also continuing to watch it's recovery
• current H1 work:
  • Kiwamu has H1 for commissioning
  • ETMs need to remain mis-aligned during his work

After yesterday's abuse, the BRSY was just not ready to contribute to the cause of science.  After having the thermal enclosure breached for an hour or something, a big jolt from something when the remote desktop session was terminated and at least one...or was it two restarts of the code, I thought things had finally settled down but it was not so.

See the attached plot the first.  Note the trend up and noisy steps in DRIFTMON.  This channel should be smooth and quiet as the low frequency beam position.  When the signal steps notice the RX (tilt) and VEL signals also going noisy and haywire. When I left the BRS last evening, the DRIFTMON was running smoothly (from about 0100 to 0200 utc.)  But then it started the step behavior again and remained unusable until restarting this morning.

Also attached. the second, is two months of the DRIFTMON and an internal temperature signal.  Obviously yesterday's incursion was a good cool down and the trend down indicates we better do another beam centering within a week or two at the longest.

The last plot is the most recent 2 hours and it appears that the periodic step and noise behavior has stopped.  The large step down in the REF signal maybe indicates that Krishna's suspicion was correct in that the reference image captured by the camera was bad.  The direction of the DRIFTMON suggests the BRS is still warming; I'll keep a close eye on this today to watch for errant tendencies.

TITLE: 03/29 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ed (Cheryl covering)
SHIFT SUMMARY: Not a very good night for science. Two short locks after the earthquake rang down, both broke to unknown causes. There were SDF diffs that came and went between these two (see mid shift summary). The third lock had a steep drop in range (see mid shift summary) and also broke due to an unknown cause. Another earthquake has just hit. The ISI config has been on WINDY_NO_BRSY all night (BRSY is rung up), except for a short attempt on WINDY. Kiwamu has begun commissioning.
LOG:

07:30 UTC Restarted DTT session on nuc4.
08:42 UTC Restarted RF45 DTT session on nuc5.
08:47 UTC NLN
08:49 UTC Restarted range integrand DMT session on video0.
08:53 UTC Accepted SDF differences (where did these come from?)
08:55 UTC LLO still down. Running a2l.
08:59 UTC a2l done.
09:01 UTC Observing.
09:04 UTC Lock loss.
09:18 UTC GRB
09:39 UTC NLN. SDF differences are back!
09:44 UTC Damped PI mode 28 by changing sign of gain.
09:47 UTC Accepted SDF differences. Observing.
10:05 UTC Lost lock damping PI mode 27, but it was no where near saturating...
10:41 UTC NLN. No SDF differences this time?!
10:56 UTC Damped PI mode 28. Notice large peak around 10 Hz.
11:10 UTC Range dropping. Peak around PCAL line at ~35 Hz has broadened.
12:13 UTC Changed sign of gain to damp PI mode 28.
13:56 UTC Lock loss. PSL noise eater oscillating.
14:02 UTC Peter to LVEA to toggle PSL noise eater.
14:07 UTC Switched ISI config from WINDY_NO_BRSY to WINDY.
14:09 UTC Bubba and Apollo to mid Y
14:10 UTC Powercycled video5
14:12 UTC Set ISI config back to WINDY_NO_BRSY.

Bubba reports that the balers started on X arm at 15:00 UTC, halfway between mid and end stations, moving towards mid station.

15:27 UTC Lockloss. Earthquake.
15:35 UTC Karen and Christina to mid stations.

The water leak on the potable water supply line to the VPW has been repaired and water is now available at the VPW.
There is still a large hole in the ground where the repair was made. The hole is taped off with caution tape and will be filled in on the next maintenance day.

08:47 UTC Made it to NLN after earthquake rang down. Found unexpected SDF differences (attached as sdf_1.png) and accepted them to go to observing. Lost lock 3 minutes later.
09:39 UTC Made it back to NLN. SDF differences returned but with reversed values and setpoints (attached as sdf_2.png). Accepted them and went to observing. Lost lock 8 minutes later.
10:41 UTC Made it back to NLN. No SDF differences this time. Went to observing. Noticed large peak around 8 Hz to about 10^-14 in DARM.

11:10 UTC Range is dropping. Peak around pcal line at ~35 Hz seems to be broadening and contracting over time (see darm.png attached). Something is not right.

TITLE: 03/29 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Earthquake
OUTGOING OPERATOR: Nutsinee
CURRENT ENVIRONMENT:
    Wind: 17mph Gusts, 12mph 5min avg
    Primary useism: 0.11 μm/s
    Secondary useism: 0.38 μm/s 
QUICK SUMMARY:

Riding out the tail end of an earthquake with the possibility of more on the way.

TITLE: 03/29 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC

STATE of H1: Earthquake

INCOMING OPERATOR: Patrick

SHIFT SUMMARY: Most of the second half of shift was down due to earthquakes. Attempting to lock but not much luck so far. Maybe seismic is still a bit high. 

LOG:

22:33 Balers done for the day.

04:18 Lockloss, there were couple of 5+ magnitudes eathquakes happened around the same time, but the seismic raised sharply to the roof implied something close by. The 6.6M earthquake in Russia was probably it.

00:00 Handling off to Patrick.

Terramon predicts R-wave to be 29.3 micron. If this is correct, we are going to be down for a whole while.

I have set the ISI config to LARGE_EQ_NOBRSXY since BRSY was still damping (and now rung up).

Summary: Injections suggest that vibration of the input beam tube in the 8-18 Hz band strongly couples to DARM and is the dominant source of noise in the 70-200 Hz band of DARM for transient truck and fire pump signals, and likely also for the continuous signal from the HVAC. Identification of the coupling site is based on the observation that local shaking of the input beam tube produces noise levels in DARM similar to those produced by global corner station vibrations from the fire pump and other sources, for similar RMS at an accelerometer under the Swiss cheese baffle by HAM2. The local shaker injections were insignificant on nearby accelerometers or HEPI L4Cs, and HEPI excitations cannot account for the noise, supporting a local, off-table coupling site in the IMC beam tube.  In addition, local vibration injections occasionally produce a 12 Hz broad-band comb, which is also produced by trucks and the fire pump, possibly indicating a 12 Hz baffle resonance.  While the Swiss cheese baffle seems the most likely coupling site, we have not yet eliminated the eye baffle by HAM3.

Several recent observations have suggested that we are limited by noise in the 100 Hz region that is produced by vibrations in the 10-30 Hz region.  There was the observation that our range increased by a couple of Mpc when the HVAC was shut down, ( https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=32886 ), and, additionally, the observations of noise from the fire pump and from trucks.

I noticed that the strongest signals in DARM produced by the fire pump and trucks had peaks that were harmonics of about 12 Hz. I injected manually all around the LVEA and found that the input beam tube was the one place where I could produce a 12 Hz comb in the 100 Hz region (injections were sub-50 Hz). Figure 1 shows that a truck, the fire pump, and my manual injections at the input beam tube produced similar upconverted noise in DARM.

I also used an electromagnetic shaker on the input beam tube.  Figure 2 is a spectrogram showing a slow shaker sweep and the strong coupling in the 8-18 Hz band. I wasn’t able to reproduce the  broad 12 Hz comb with the shaker, possibly because, as mounted, it didn’t couple well to the 12 Hz mode. But the broad-band noise produced in DARM by the shaker is more typical of trucks and the fire pump: only occasionally does the 12 Hz comb appear.  One possibility is that the bounce mode of the baffle is about 12 Hz.

Figure 3 shows that, for equivalent noise in DARM, the RMS displacement from the shaker and the fire pump were about the same at an accelerometer mounted under the Swiss cheese baffle by HAM2. Figure 4 shows that the shaker vibration is local to the beam tube. While the shaker signal is large on the beam tube accelerometer, it is almost lost in the background at the HAM2 and 3 accelerometers and the HAM2, 3 L4Cs.  Finally, the failure to reproduce the noise with HEPI injections, both during PEM injections at the beginning of the run and a recent round by Sheila, further support the off-table source of the noise.

While everything is consistent with coupling at the Swiss cheese baffle near HAM2, we haven’t eliminated the eye baffle near HAM3. This might be done by comparing a second accelerometer under the eye baffle to the one under the Swiss cheese baffle, but I didn’t have another spare PEM channel.

If it is the Swiss cheese baffle, it might be worth laying it down during a vent. Two concerns are the blocking of any beams that are dumped on the baffle, and the shiny reducing flange at the end of the input beamt ube that would be exposed.

An immediate mitigation option is to try and move beams relative to the Swiss cheese baffle while monitoring the noise from an injection. Sheila and I started this but ran out of commissioning time and LLO was up for most of the weekend so I didn’t get back to it.  If someone else wants to try this, either turn on the fire pump or, for even more noise in DARM, the shaker by HAM3 (the cable goes across the floor to the driver by the wall, enter 17 Hz on the signal generator and turn on the amp, it should still be set).

Shaker injections have shown the input beamtube to be sensitive for some time ( https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=31016). During pre-run PEM injections, an 8 to 100 Hz broad-band shaker injection on the input beamtube showed strong coupling. However the broad-band injection was smaller in the sensitive 10-18 Hz band then in other sub-bands and so the magnitude of the up-converted coupling from this narrow sub-band was not evident. When we have detected upconversion during PEM injections in the past, we have narrowed down the sensitive frequency band with a shaker sweep, but, for the input beam tube, we didn’t get to this until last week.

Figure 5 shows fire pump, trucks and the HVAC on input beam tube accelerometers and DARM.

Sheila, Anamaria, Robert

Been locked and Observing for 3 hrs 44 mins. Wind is coming down. BRSY is still not in use. Not much else going on.

It appears that some maintenance work on Tuesday March 14 led to degradation
with respect to narrow lines in H1 DARM. The attached inverse-noise-weight spectra 
compare 1210 hours of data from the start of O2 until early morning of March 14 with 
242 hours since that time.

Summary of substantial comb changes:

The comb with 0.9999-Hz spacing nearly aligned with N + 0.25 Hz (N = 15-55) is stronger.

There is a new comb with 0.999984-Hz spacing visible nearly aligned with N + 0.75 Hz (N = 41-71)

There is a new comb with 1.0000-Hz spacing visible at N - 0.0006 Hz (N = 104-125)

Much activity was reported in the alog for March 14, but what jumps out at me
are two references to HWS work: here and here. 

Are there HWS cameras running during observing mode? 

I had thought those things were verboten in observing mode, given their
propensity to make combs.

Fig 1: 20-50 Hz comparison (before and after March 14 maintenance)
Fig 2: 50-100 Hz (before and after March 14 maintenance)
Fig 3: 100-150 Hz  (before and after March 14 maintenance)

Attachment has full set of comparison sub-bands up to 2000 Hz with both A-B and B-A orderings to make clear which lines are truly new or louder.

J. Kissel, S. Aston, P. Fritschel

Peter was browsing through the list of frame channels and noticed that there are some differences between H1 and L1 on PR2 (an HSTS), even after we've both gone through and made the effort to revamp our channel list -- see Integration Issue 6463, ECR E1600316, LHO aLOG 30844, and LLO aLOG 29091.

What difference he found is the result of the LHO-ONLY ECR E1400369 to increase the drive strength of the lower states *some* of the HSTSs. This requires the two sites to have a different front-end model library part for different types of the same suspension because the BIO control each stage is different depending on the number of drivers that have been modified;
At LHO the configuration is
    Library Part        Driver Configuration            Optics
    HSTS_MASTER.mdl     No modified TACQ Drivers        MC1, MC3
    MC_MASTER.mdl       M2 modified, M3 not modified    MC2
    RC_MASTER.mdl       M2 and M3 modified              PRM, PR2, SRM, SR2

At LLO, the configuration is
    Library Part        Driver Configuration            Optics
    HSTS_MASTER.mdl     No modified TACQ Drivers        MC1, MC3, PR2
    MC_MASTER.mdl       M2 modified, M3 not modified    MC2, PRM, SR2, SRM
    RC_MASTER.mdl       M2 and M3 modified       none

This model's DAQ channel list for the MC and RC masters is the same. The HSTS master is different, and slower, because these SUS are used for angular control only: 
                           HSTS (Hz)        MC or RC (Hz)
    M3_ISCINF_L_IN1        2048               16384

    M3_MASTER_OUT_UL       2048               16384
    M3_MASTER_OUT_LL       2048               16384
    M3_MASTER_OUT_UR       2048               16384
    M3_MASTER_OUT_LR       2048               16384

    M3_DRIVEALIGN_L_OUT    2048               4096

Since LLO's PR2 does not have any modifications to its TACQ drivers, it uses the HSTS_MASTER model, which means that PR2 alone is going to show up as a difference in the channel list between the sites that seemed odd Peter -- that L1 had 6 more 2048 Hz channels than H1. Sadly, it *is* used for longitudinal control, so LLO suffers the lack of stored frame rate.

In order to "fix" this difference, we'd have to create a new library part for LLO's PR2 alone that has the DAC channel list of an MC or RC master, but have the BIO control logic of an HSTS master (i.e. to operate M2 and M3 stages with an unmodified TACQ driver). That seems excessive given that we already have 3 different models due to differing site preferences (and maybe range needs), so I propose we leave things as is, unless there's dire need to compare the high frequency drive signals to the M3 stage of PR2 at LLO.

I attach a screenshot that compares the DAQ channel lists for the three library parts, and the two types of control needs as defined by T1600432.