TITLE: 04/03 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 70Mpc
OUTGOING OPERATOR: Cheryl
CURRENT ENVIRONMENT:
Wind: 2mph Gusts, 1mph 5min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.43 μm/s
QUICK SUMMARY: No issues were handed off. Locked at NLN for ~22 hours.
TITLE: 04/03 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 69Mpc
INCOMING OPERATOR: Travis
SHIFT SUMMARY: locked all shift
LOG:
in the last 45 minutes PI mode 23 has spiked a number of times - snapshot of the striptool attached
I found this in alog 34787:
"* IMPORTANT: Driving PI mode 23 (for instance when applying damping filters) caused glitchy narrow lines at (14.5, 64.0, 78.5 and 142.5 Hz), this dominated Omicron glitchgram with a 60-80Hz band of high SNR glitches. Commissioners have noticed this an put in place a practice of not damping this mode anymore unless required for lock acquisition."
It looks like mode 23 might be related to the drops in range - see attached plot.
Ya, as of now do NOT damp this mode.
We think this mode may actually be acting as a witness to something else going 'bad', meaning - as you've noticed - it's amplitude does anticorrelate with range but is likely a response as opposed to the cause. I'm trying to figure out how, but for now you should just ignore it. If it starts ringing up steadily/exponentially like other modes, we can look back into damping it.
TJ, could you increase the set point of the verbal alarm for this mode so we don't hear it unless its quite high?
TITLE: 04/03 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 70Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
Wind: 7mph Gusts, 6mph 5min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.47 μm/s
QUICK SUMMARY:
TITLE: 04/03 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 70Mpc
INCOMING OPERATOR: Cheryl
SHIFT SUMMARY: Locked for 13hrs, nothing really to note for my shift.
LOG:
TITLE: 04/02 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 68Mpc
OUTGOING OPERATOR: Travis
CURRENT ENVIRONMENT:
Wind: 19mph Gusts, 16mph 5min avg
Primary useism: 0.12 μm/s
Secondary useism: 0.45 μm/s
QUICK SUMMARY: Wind around 20mph but looking like it s dropping, useism higher than usual, 6hr lock.
TITLE: 04/02 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 69Mpc
INCOMING OPERATOR: TJ
SHIFT SUMMARY: One lockloss of unknown cause. Otherwise no issues with relocking or wind (wind is still at ~30mph, but not effecting range).
LOG: See previous aLogs.
Following up on this earlier observation of a change point in DARM combs on March 14 and on comments added by Evan and Ansel, I tried looking at possible correlations between optical lever laser power levels and combs seen in EX and EY magnetometers. The bottom line is that there are such correlations, as documented in detail in the attached annotated slides with posted spectra at a variety of power levels (as measured by H1:SUS-ETMX/Y_L3_OPLEV_SUM_OUT_DQ). The figures below show EX and EY before/after spectra. In summary, the spectra show narrow lines before March 14 in combs of ~1-Hz spacing with various offsets (EX worse than EY). During periods when the laser powers were lowered, the spectra were contaminated by broadband noise (motivation for keeping the power high, I believe). When the power was raised to higher than it was prior to March 14, the broadband power dropped again, the lines persisted and were joined by new lines with 1-Hz spacing offset from integer frequencies by ~0.25 Hz, a comb observed to be present in DARM following March 14. The apparent creation of a new comb in DARM from these lasers may hint that other combs seen for a long time in DARM and in magnetometer spectra may also arise from these lasers. Whether the mechanism is though the optical lever damping, as suggested previously for glitches, or through another coupling, such as ESD power supply contamination from the laser supplies, is not clear to me. Fig 1: EX magnetometer spectrum before maintenance work on March 14 (Interval "A" on 1st attached slide file) Fig 2: EY magnetometer spectrum before maintenance work on March 14 (Interval "P" on 1st attached slide file) Fig 3: EX magnetometer spectrum before maintenance work, on March 15 (Interval "Q" on 1st attached slide file) Fig 3: EY magnetometer spectrum before maintenance work, on March 15 (Interval "V" on 1st attached slide file) Attachment 1: Annotated slides showing spectra before / after many change points on March 14/15 of EX laser power Attachment 2: Annotated slides showing spectra before / after a handful of change points on March 14/15 of EY laser power
Heads up on this: Jason plans to swap the ETMY laser tomorrow (see WP 6555), not necessarily because of this study, but it'll be another "before vs. after" data point. Also -- do we suspect a coupling mechanism for this correlation to DARM? The bandwidth of the optical lever damping loops is quite narrow around 0.3-0.5 [Hz], and control is applied only at the penultimate stage, which means it'll get a factor of 1/f^2 above ~5 Hz. Further, it's angular control as well, so you'd need a pretty high angle-to-length coupling coefficient... Did you see any improvement in the combs seen in DARM after Sheila installed a better cutoff filter (see LHO aLOG 34988)?
Following up on Jeff's question, below are spectral comparisons of pre-March 14, the period between March 14 and March 21, and the period afterward. I don't see evidence of a significant change in the comb structure in DARM after the damping loop rolloff adjustment on March 21. Included are zooms around four teeth in the 1-Hz comb on 0.25-Hz offsets from integer frequencies. Fig 1: 20-60 Hz Fig 2: Zoom around 20.25 Hz Fig 3: Zoom around 21.25 Hz Fig 4: Zoom around 22.25 Hz Fig 5: Zoom around 23.25 Hz
Nothing apparent on FOMs. Unknown cause.
Back to Observing at 17:21 UTC.
TITLE: 04/02 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 61Mpc
OUTGOING OPERATOR: Jeff
CURRENT ENVIRONMENT:
Wind: 35mph Gusts, 30mph 5min avg
Primary useism: 0.15 μm/s
Secondary useism: 0.44 μm/s
QUICK SUMMARY: High winds are affecting our range a bit, but we have been locked for ~24 hours.
Looking at the summary pages, it looks like the range drop is coincident with increase in the 10-30 blrms motion at the corner station. I suspect the recent wind-related range drop/glitches are related to the 8-18 Hz input beam-tube vibration-related coupling that Robert and co. showed recently. This is probably not surprising to most, but I just wanted to suggest this explicitly since wind wasn't mentioned in Robert's alog. Hopefully fixing that problem will also fix wind-range coupling.
Shift Summary: Run A2L check script; Both Yaw and Pitch are elevated. Will run the correction script when possible.
Overall a good observing shift.
In the last hour, the wind has come up to Near Gale conditions with gusts well into the full Gale range (40 mph+). Primary microseism for the End Stations has correspondingly risen to near 0.9um/s. Range has dropped to 63.9 Mpc. There is a 0.723um/s R-Wave predicted to hit the site around 15:00 (08:00), the result of a Mag 5.2 earthquake near Bengkulu Indonesia. So far, no indications of the R-Wave arrival.
10:36 (03:36) GRB Alert - Both sites in Observing
Beam position based on exciting the pitch(yaw) DOF and then changing P2L(Y2L) gain to minimize the peak. Both measurements use a sign convention that is consistent with UR coil values. The Dec 2013 alpha numbers are as posted, however the beam distance numbers have been recalculated. In Dec 2013 the conversion from alpha to mm was 37.5mm/alpha, and the current conversion is 42.2mm/alpha.
| 13 Dec 2013 | 21 Mar 2017 | change | |||
| alpha | beam distance from center, mm | alpha | beam distance from center, mm | mm | |
| MC1 pitch | -0.043 | +1.81 | -0.057 | +2.42 | +0.6 |
| MC1 yaw | +0.029 | +1.22 | +0.089 | +3.76 | +2.5 |
| MC2 pitch | -0.062 | +2.62 | -0.183 | +7.72 | +5.1 |
| MC2 yaw | -0.048 | -2.03 | -0.020 | -0.084 | +1.2 |
| MC3 pitch | +0.041 | -1.73 | -0.051 | +2.15 | +3.9 |
| MC3 yaw | -0.052 | -2.19 | -0.135 | -5.70 | -3.5 |
The animation that's attached shows the ideal IMC alignment in a dashed magenta line, the Dec 2013 alignment in red, and the Mar 2017 alignment in blue. Green markers show the optics, squares are MC1, triangles are MC2, and circles are MC3.
The lines and markers accurately represent the optics and the beam changes, but are not to scale. I altered some numbers to make the changes visible in this animation.
| 13 Dec 2013 | 21 Mar 2017 | change | |||
| alpha | beam distance from center, mm | alpha | beam distance from center, mm | mm | |
| MC2 yaw | -0.048 | -2.03 | -0.020 |
-0.84 |
+1.2 |
TITLE: 04/02 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 53Mpc
INCOMING OPERATOR: Jeff
SHIFT SUMMARY: Locked for 15.5hours, wind has been a steady 15mph and useism is rising up to 0.5um/s. There was a large glitch just now that is showing up on the glitchgram in almost the entire shown frequencies.
LOG:
06:52 GRB
See red and blue VS green. Bumps are at around [4, 5, 6, 7, 8]*12.125 Hz or so.
When it was really bad (red), it was easily identifiable in detchar summary page, not so when it was mildly bad (blue).
I ran coherence tool on these lines. I first tried to find a comb over there but failed. Then I tried to find them as single lines. I looked for 6 single lines: 12.125Hz, 48.5Hz, 60.625Hz, 72.75Hz, 84.875Hz, 97Hz. Two of them are not found in the coherence tool. Here are the results:
12.5Hz: https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_line_12.125/index.html (Weak results and the structure does not look like a single line)
48.5Hz: https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_line_48.5/index.html (Found in four of the weeks, in some EX and EY magnetometers. There are some channels that do not look like a single line. But there seems to be something going on so I showed them.)
60.625Hz: https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_line_60.625/index.html (Not found)
72.75Hz: https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_line_72.75/index.html (Not found)
84.875Hz: https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_line_84.875/index.html (Weak. Only found in one channel and the structure does not look a single line)
97Hz: https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_line_97/index.html (Found in many EX and EY magnetometers)
Robert's measurements seem to suggest that this is the resonance of one of the baffles.
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=35166
