Added more insulation to the BRSY auxcillary table supporting the T240 seismometer, see 35147, on Tuesday.  We saw improvement in the low frequency noise after insulating the supporting legs of the table, see 34869, so more on the table was warranted.

Attached are spectra before and after.

It is a little hard to see but I think the story is good.  The upper plot shows the Y axis and the X axis traces are below.  The reference traces are from 26 March 1000utc when the wind was very low.  The current traces are from 31 March 1120utc, two days after the insulation was added to the table.  Generally, comparing suggests the insulation has improved things below 60mHz.  Maybe little improvement on Y below 10mHz.

15:42UTC

TITLE: 03/31 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 67Mpc
OUTGOING OPERATOR: Jeff
CURRENT ENVIRONMENT:
    Wind: 6mph Gusts, 5mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.23 μm/s
QUICK SUMMARY:

Shift Summary: Run A2L check script; Yaw is up around 0.8, Pitch is below reference. Will run the repair script at first opportunity. Ran A2L script while LLO was down. Environmental and seismic conditions remain favorable. Other than 2 large glitches, there were no issues or problems worth noting during this shift.  

  Quiet first half of the shift. Dropped out of Observing for 8 minutes to run the A2L script while LLO was down. No other problems to report.

TITLE: 03/31 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 67Mpc
INCOMING OPERATOR: Jeff
SHIFT SUMMARY: Locked for almost 26hours, wind has calmed a bit.
LOG:

• ~23:30 Balers finishing the day around MY
• 01:41 GRB

23hrs and counting ay 65Mpc.

The new red lines are a very nice touch, kudos to whomever did that. Everything seems to be in its normal operating range and the Sums may even be up a slight bit for a few of them.

FAMIS:4721

Added 50 ml.

Closed FAMIS#6516

WP6548 Remove MY compressed air channels from cell phone alarm system

Bubba, Chandra, Dave:

Following the stand-down of the MY air compressor this afternoon, its channels were removed from the cell phone alarm system and the code was restarted.

TITLE: 03/30 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 65Mpc
OUTGOING OPERATOR: Ed
CURRENT ENVIRONMENT:
    Wind: 17mph Gusts, 12mph 5min avg
    Primary useism: 0.08 μm/s
    Secondary useism: 0.22 μm/s
QUICK SUMMARY: Currently on a GRB stand down. Our range has been trending down for the last ten hours, not sure why yet.

TITLE: 03/30 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 50Mpc
INCOMING OPERATOR: Nutsinee
SHIFT SUMMARY:

Fairly quiet day. a2l was run once. It need to be run again at next opportunity. Some NOISEMON injections were run by Evan and Miriam while Livingston was down. A flurry of small earthquakes late in te shift posed no real threat to our lock. Handing off to TJ
LOG:

15:08 H1 out of Observing for Richard to measure TCS table

15:13 Observing

16:36 Karen driving to VPW

19:24 running a2l

19:25 Miriam wants to run NOISEMON injections for test as per WP#6545

19:45 Betsy and Travis to MY

20:47 KingSoft here to check RO. He knows about Observation protocol for onsite driving.

20:56 Betsy and Travis back

22:45 Big glitch in BNS range (didn't catch it in DARM). h(t) shows glitch as fairly broadband

I have turned off the instrument air compressors at Mid Y. These will remain off until needed, (same as Mid X) but in a stand-by mode.

22:31UTC INJ_TRANS guardian doing it's thing.

Travis left just before the alert to drop some boxes at a Mid station and the balers headed in the direction of Y arm yet they may be by the H2 building. ( I can't find them on the camera)

[Jeff Kissel, Aaron Viets]

Recent issues with the calibration lines and kappa calculations have raised questions about how the h(t)-ok bit is affected by the kappas (see https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=35184 ).

For CALIB_STATE_VECTOR documentation, see https://wiki.ligo.org/viewauth/Calibration/TDCalibReview#CALIB_STATE_VECTOR_definitions_during_ER10_47O2.

For each kappa, there is a "median-ok" bit and a "smooth-ok" bit. The "median-ok" bit tells whether the kappas are being gated due to bad coherence (thus "corrupting" the median with previously measured values). The "smooth-ok" bit tells whether the kappa values are in an expected range (1.0 +- 0.2). Since the coherence was bad, but the gating worked during the time documented in the aforementioned aLOG, the median-ok bit was off and the smooth-ok bit was still on. When we apply the kappas, h(t) OK depends on the smooth-ok bits and not on the median-ok bits, so it was unaffected by this. If, on the other hand, we do not apply the kappas, the kappa bits do not affect the h(t) OK bit.

The above description has been the case since the start of ER10, with the exception of one slight change:
On 2016-11-29 Tuesday maintenance (near the start of O2), the smooth-ok bits were generalized further to also mark bad any time when the kappas are equal to their default values (indicating they have not yet been computed by the pipeline). This scenario is only expected to possibly occur at the start of the first lock stretch following a restart of the pipeline. The purpose of this change was to insure that "h(t)-ok" implies "kappas-applied quality" when we are, in fact, applying the kappas. For documentation on this change, see:
https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=29947
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=31926

Eric Quintero, Rana

Summary:

Studying coherences between the ground and the LSC drives, we find that we can reduce the longitudinal forces to the mirrors in the 0.1-0.3 Hz band by a factor of ~2-5 in most cases, for both sites.

Details:

The recent success of the length to angle (L2A) feedforward at LLO led us to wonder about the source of so much low frequency motion. The SEI loop feedback and feedforward has been heavily tuned over the years to reduce much of the motion. By looking at the coherence and transfer function between the ground seismometers and the LSC*OUT signals (in a similar manner to what we did with the length to angle in May 2016), we are able to make an upper limit estimate on how much this can be reduced by implementing a global FF (just as we did in early 2010 for the S6 run using HEPI/PEPi).

We took 1 hour of data from 1000 UTC on March 12. The RMS of the ground motion in the 0.1-0.3 Hz band was 0.5 um/s, which is high, but only moderately high for the winter time. The summer time motion is more like 0.1 um/s.

The attached plots show:

upper plot: LSC control signal & LSC control signal after ideal subtraction

lower plot: top 5 signals used in the subtraction (in practice, using ~3 signals is enough to do the biggest part of the subtraction)

This subtraction is done on a bin-by-bin basis in the frequency domain, and as such, its a best case estimate. In reality, implementing a causal filter which avoids injecting too much noise at 3-20 Hz will degrade the subtraction performance somewhat. We are now working on making a frequency dependent weighting so as to make realizable filters.

In the attached channel list, you can see that all ground seismometers and tiltmeters were used.

1. In some cases, the tiltmeters do seem to be useful for doing this FF, although it remains to be seen if their noise at > 3 Hz is too high to preclude using them.
2. As we also see for LLO, much of the motion is coming in through the Z direction. This implies that the vertical to horizontal coupling in the ISI (perhaps due to imbalances in the sensor calibrations?) is the culprit. In any case, we can fix it by FF just to improve the performance of the interferometer in the near term and then address the root cause at a later time.
3. These LSC_OUT signals are just the control signals at the output of the LSC sub-system, but they are not really equivalent to force or displacement, since the filters inside the suspensions distribute the signals among the upper suspension stages with different filter shapes and crossovers: the suspensions do not 'look' like a simple pendulum from the LSC side. Some complicated suspension model + digital filter forensics should be able to convert these plots into physical units so we could figure out how much the motion reduction would really be, but I expect that the bulk of the relative motion between the mirrors and chambers comes from 0.1-0.3 Hz, as does the angular motion that the WFS loops have to deal with. It would be very handy if there was a matlab function that could read in a simplified suspension model and the digital filters / gains for a specified GPS time and return the calibration to go from LSC counts to meters.
4. We will need to do some minor model changes to be able to bring the seismo signals into the LVEA at 2 kHz and then to send out the ~10 Hz BW signals to the various ISIs. There's some discussion between Joe B. and Jenne to clarify precisely what and how many changes.
5. For LHO only, I've also used the BRS channels: H1:ISI-GND_BRS_ETMX_RY_OUT_DQ & H1:ISI-GND_BRS_ETMY_RX_OUT_DQ, which look like they are the right ones. But, it seems that they do not contribute to any significant subtraction during this period. IF they were already being used at this time, then perhaps that just means that their FF filters are already well tuned.

Evan, Miriam,

We continued the blip-like injections as in aLog 35116. This time we could inject a few different shapes.

In the first set we injected a sine-gaussian with frequency 200 Hz. Again we started quiet, only times with * can be seen in DARM:

1174937465

1174937493

1174937520

1174937554 *

1174937649

1174937693 *

1174937758 *

1174937786 *

1174937836 *

In the second set we injected one of the blip glitches that showed a strong residual after the subtraction of the ETMY L2 MASTER signal from the NOISEMON (see aLog 34694). Since we are injecting in the DRIVEALIGN, we took the shape of the blip in that channel and injected that. Times (all can be seen in DARM, they should have three different SNRs):

1174937920 *

1174937956 *

1174938062 *

1174938144 *

1174938198 *

1174938231 *

In the final set, we injected a filtered step function that was sent to us by Andy. The first time was too quiet and did not show up in DARM, the second shows up quietly, and the third was fairly loud:

1174938333.5

1174938365.5 *

1174938397.5 *

Right after injecting the last one, the spectrum was showing some mid frequency (100 - 300 Hz) noise, which can be seen together with the injection in this omega scan. We did not believe this noise was originated by our injection, and we saw similar noise about half an hour later when we were back in observing mode, but we will try to inject it again at another opportunistic time just as a sanity check (L1 came back up after our last injection so we didn't want to take any more time).

NOTE: same as with the set of injections mentioned in the aLog pointed above, and as pointed also in aLog 35223 (first comment), these injections were performed while L1 was down and with H1 in comissioning mode. This means that none of these injections happened in coincident time, and that they are not included in analysis ready segments (as can be seen, for instance, in the summary pages).

19:21UTC