travis.sadecki@LIGO.ORG - posted 15:24, Monday 03 April 2017 - last comment - 15:40, Monday 03 April 2017(35297)
GRB alert
GRB alert 22:23 UTC. Begin 1 hour standdown.
GRB alert 22:23 UTC. Begin 1 hour standdown.
J. Kissel WP #6557 In order facilitate regular, bi-weekly, CAL measurements, I've added a new state to the ISC_LOCK guardian code called "NLN_CAL_MEAS." So far, the state only turns OFF all calibration lines, as is needed for the frequency dependent sweeps. Upon request to return to NOMINAL_LOW_NOISE, it turns the calibration lines back on, and clears the history in the calculations for front-end calculated time-dependent correction factors (which, sadly, will take several minutes given the impulse responses of some low pass filters in the calculation). I'll install and test the state tomorrow (4/4) after maintenance is complete. Thus far, I've only - checked for a clean svn status before I started, - written in the change to the ISC_LOCK guardian, - saved it, - checked if the graph was OK with the new edges, - commented out all new code - committed ISC_LOCK to the svn so if the code, for whatever reason, gets loaded before tomorrow, there will be no change applied. I attach the test of the new edges and the representative graph to show how this state fits in the bigger picture.
Peter, Jason, Vern, Nutsinee
We thought it's worth to get some most recent ITMY data to compare along side with ITMX to make sure there's no obvious shmud on the ITMY surface. Given the wrong in vac lens and the possibility that the alignment might have changed we might not get anything useful. But if the alignment is good in theory we should still be able to see if there's anything wrong on ITMY surface by subtracting the final gradients after power-up/lockloss from the reference (taken while resonates at 2W).
Because the two cameras can't be run at the same time, I swapped the fiber so that h1hwsmsr machine is now talking to the HWSY camera rather than HWSX camera. Data written to /data/H1/HWS_ITMX starting from 20:19:29 UTC is data from ITMY surface.
Log:
20:08 UTC HWS code stopped
20:15 UTC cable swapped
20:19 UTC HWS code restarted, now writing data from HWSY camera
The HWSY SLED has been turned on also.
No issues relocking after EQ ringdown. A slight tweak of ETMx was all that was required.
Was it reported by Terramon, USGS, SEISMON? Yes, Yes, No
Magnitude (according to Terramon, USGS, SEISMON): 6.5, 6.5, NA
Location: 132km W of Moijabana, Botswana; LAT: -22.6, LON: 25.2
Starting time of event (ie. when BLRMS started to increase on DMT on the wall): 18:05 UTC
Lock status? H1 and L1 both lost lock. L1 lost lock ~45 min. before H1. Not sure if the cause of LLO's lockloss was actually the EQ.
EQ reported by Terramon BEFORE it actually arrived? Yes, at least before it got large enough to break lock.
6.5M EQ in Botswana took us down. LLO was already down by the time we lost lock.
Starting CP3 fill. LLCV enabled. LLCV set to manual control. LLCV set to 50% open. Fill completed in 18 seconds. TC A did not register fill. LLCV set back to 18.0% open. Starting CP4 fill. LLCV enabled. LLCV set to manual control. LLCV set to 70% open. Fill completed in 102 seconds. LLCV set back to 35.0% open.
Everything appears normal. The chiller plots were generated pretty zoomed and aren't visually what I'm used to seeing but I think the fluctuations are rather normal.
Concur with Ed, everything looks normal here.
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
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
This may be a false alarm. Got a call from Anamaria at LLO who noticed that the GPS time reported for this GRB was ~20000 seconds before the alert arrived. I have confirmed that our CAL_INJ_CONTROL MEDM screen reports the same discrepancy for the last alert.