J. Kissel (B. Weaver, S. Dwyer)
FRS Ticket 6852

It was recently identified that a Dec 05 lock loss looked suspiciously cpoincident with a glitch in the H1 SUS SR3 M1 T1 and LF OSEMs (see LHO aLOG 32220). The same OSEMs were suspected in a subsequent Dec 06 lock loss (LHO aLOG 32251), and thus an FRS ticket was filed (FRS Ticket 6852), but was later deemed too confusing to draw conclusions (see brief mention of it in LHO aLOG 32279).

Betsy then went back to find the minute trends of the SR3 OSEM noise appeared suddenly louder after the Dec 05 glitch/lock loss in a 5 day trend surrounding the glitch (split into LHO aLOGs 32280 and 32281).

In this aLOG, I investigate further by zooming into 10 minutes surrounding the Dec 05 glitch. I attach three plots:
- A 10 minute trend of second trends for the suspect channels, both in terms of uncalibrated EPICs records (the same that Betsy chose to use in her aLOG) and in calibrated fast channels (stored at 256 Hz). The EPICs records show a similar sudden increase in amplitude of max and min trends, but the calibrated fast channels do not. T1 shows a much larger increase in max/min noise than LF.
- A full-data time-series of the same to channels in the same two formats. Same thing here regarding the sudden increase in noise in T1 INMON, but only a brief glitch in LF's INMON. Again, no such obvious change in behavior on the fast channels. Interestingly, it looks like there's smaller glitch in T1's fast channel 107 [sec] earlier.
- An amplitude spectral density of the calibrated fast channel before and after the glitch happens (15:57 UTC vs 16:06 UTC, 0.04 Hz BW ASD). There's no obvious difference between these spectra. This points to either the excess noise showing up in the INMONs is at higher than ~100 Hz, or the EPICs records are just reporting bogus information. Because I'm suspicious of the apparently incredibly low microseism, I also attach BLRMS of the microseism on the ground and on the ISI around this time. Indeed, the GS13s seem to confirm that the RMS velocity is somewhere around 5 [nm/s], which is roughly equivalent to ~5 [nm] at 0.15 Hz, which in the right ballpark of what the OSEMs report of 2-4 e-3 [um] or 2-4 [nm] or 2-4 [nm/s].

In conclusion -- still no evidence for anything more than a one-time glitch, and there is now little-to-no evidence for permanently different noise behavior after the glitch. We need to wait for more occurances of this issue with obvious evidence before we go for making any change to the instrument.

TITLE: 12/08 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 68.7782Mpc
OUTGOING OPERATOR: Jeff
CURRENT ENVIRONMENT:
    Wind: 10mph Gusts, 8mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.29 μm/s
QUICK SUMMARY:  Observing for 23 hours now.

0:10 Intent bit set to commissioning so Evan can turn off high frequency PCal line for HW inj.

0:11 Evan accepted the new SDF diff for PCal, so we went back to Observe.

0:17 Injection gain ramping dropped us out of Observe, Evan set this gain to 'Not Monitored', and we were back to Observe within the minute

0:34 PCal HF line turned back on, out of Observe.  I am running a2l since it looks like it is time, and Sheila is opportunistically working one of her work permits.
 

I turned off the 4301.3 Hz Pcal line at 00:10 Dec 8 2016 UTC for the planned stochastic injection. This dropped us from observing intent for a brief time. I updated the SDF and we returned to observing. I will turn the line back on once the stochastic injection has concluded.

I've scheduled a coherent stochastic injection for 00:20 UTC (16:20 PT). It will take 13 mins. The update to the schedule file is:

1165191617 H1L1 INJECT_STOCHASTIC_ACTIVE 1 1.0 stoch/Waveform/SB_ER10_{ifo}.txt

'Double modes' seen in some PI mode bands are not from test mass resonances, in agreement with model conclusions. Follow up on this .

I've looked at frequency shifting of the peaks seen in the 15060 - 15090 Hz range during 11 hours of the current lock.

• Four predictably follow the drumhead modes of the four test masses; these are the respective ~15070 Hz resonant modes (blue, green, orange, red)
• Four show no following drift, indicating they're not tied to mechanical modes of the optics which would increase as the optic heats up (steel, grey, light pink, mauve)
• One has similar behavior/timing of a resonant mode but shifts down in frequency; aliased down from an upward shifting resonance at 50451 Hz (similar to suggestion by Slawek here)? (pink).
• The last peak is questionable. It does shift over the 11 hours, but doesn't seem to be following one of the test mass drumheads and the Q is ~15 K as opposed to test masses ~20 M (lavender) 

Attached plots:

• spectrum showing the peaks at beginning of lock and 11 hours into it & plot of frequency drifts. Dots over peaks correlate to color mentioned above and color of line in next plot
• plot showing change of frequency, first two hours of lock and 9th and 10th hour of lock. Colors match those mentioned above and peaks in spectrum. I've also included the known ~8160 Hz drumhead modes of the test masses and matched the 15070 Hz mode that follows to that color. 

3:48 pm local

Took 30 sec to overfill CP3 by raising LLCV from 18% to 50% open. I lowered back to 17% since there was some pressure at exhaust and fill time was so fast.

   The dust monitor alarm levels have been set to their correct values. All future alarms should be treated as valid and should be investigated. Please open an aLOG and notify Jeff B.

CP4 appears to have joined with the disfunctioning CP3 and is now being investigated by Kyle and Chandra. Until further notice operators should expect false level indications at CP4.

Attached is a trend of the corner EtherCAT Device0 channels while there was a broken module on 11/26, see alog 31854. The error can be seen in the ERROR_FLAG, SLAVE_COUNTERROR and the FRAMEWORKINGCNTs. The SLAVECOUNTACTUAL dropped from 345 to below 50—indicating a broken link or module.

On Nov 1 chassis 3 was pulled for some repairs, see alog 31081. The Device0 channels showed similar behavior.

On Nov 15 the power supply was changed for the baffled PD controllers, see alog 31509. This temporarily removed 4 modules from the EtherCAT chain. Again, we can see this clearly in the Device0 channels.

The last plot shows frame rates. Most frames seem to be lost during the above repairs and modifications.

No errors were detected in the end stations.

Reveived a second GRB Alert at 20:50 (12:50PT). Both sites in Observing mode. Will extend the hold until 21:50 (13:50PT)

 Received GRB alert at 20:05 (12:05PT) - LLO received same. Both IFOs in Observing mode. Will observe hold until 21:50.  

With the ASC IMC model now running at 16384 Hz we look at the coherence of jitter as measured by the IMC WFS and other channels up to 7.4 kHz. Not sure we can conclude anything except that pointing errros contaminate everything.

We can compare this with an older 900-Hz bandwidth measurement from alog 31631 which was taken before the piezo peak fix (alog 31974).

TITLE: 12/07 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 70.7388Mpc
INCOMING OPERATOR: TJ
SHIFT SUMMARY:  Pretty smooth shift as far as locking goes.  Some excitement regarding CP4 (see aLog 32283).  Also, set some arbitrarily high thresholds for most dust monitors to stop alarms.  JeffB will reset them tomorrow.  Locked for over 6 hours now.
LOG:

3:35 CP4 alarm

5:24 GRB alert, contacted LLO who verified that they received the alert, begin standdown

6:24 GRB standdown end

7:10 PI mode 27 ringing up, changed phase from 20 to 120.  Did not go out of Observe.  Are we supposed to go out of Observing to make PI mode changes??
 

As a benchmark against which to compare upcoming O2 data, I have compiled a list
of narrow lines seen in the H1 DARM spectrum up to 2000 Hz, using 107 hours of
ER10 FScan 30-minute SFTs. There are no big surprises relative to the lines and combs
Ansel and I have reported on previously from ER9 and later data, but below are some
observations. 

Attached figures show  selected band spectra, and a zipped attachment
contains a much larger set of bands. Also attached for reference is a plaintext list of combs, 
isolated lines, PEM-associated lines. etc. In the attached spectra, the red curve is the
ER10 data, and the black curve is the full-O1 data. The label annotations are keyed to
the height of the red curve, but in some cases, those labels refer to lines in the O1 data
that are not (yet) visible in accumulated current data. For the most part, lines seen in 
O1 that don't show up in ER10 nonetheless remain for now in the lines list and still
have labels on the graphs that end up in the red fuzz. If they fail to emerge in O2
data, they will be deleted from future line lists.

Observations:

As noted previously, the 8-Hz / 16-Hz combs seen in O1 are blessedly gone
Thanks to interventions to upgrade timing electronics firmware, the previously dominant low-frequency comb
with 1-Hz spacing and 0.5-Hz offset is greatly reduced (but not eliminated)
Compared to O1, the non-linear upconversion around quad violin modes and harmonics
is much worse in ER10, and it appears that at least some violin mode excitations are
affecting the low frequency band in that one sees there a multitude of sparsely distributed
doublets, triples and quadruplets of lines with a  spacing of about 0.0468 Hz.
Andy Lundgren pointed out that this spacing coincides closely with a beat between
two 2nd-harmonic violin modes he reported on last week. 
If I measure / eyeball those frequencies as seen in the ER10 data set, I get 1009.4414 and 1009.4881 Hz, giving
a beat of 0.0467 Hz (but with an uncertainty of a few tenths of a mHz), consistent with the explanation.
Further credence comes from the proliferation of such doublets / triplets / quadruplets seen in the wings of
the quad harmonics (fundamental and higher). 
There are so many upconverted lines around the quad harmonics that I didn't bother cataloguing them
in those regions on the assumption that they will go away in O2 with improved damping 
(but cataloguing can be revisited later, if needed). 
 With the exception of the violin mode regions, the higher frequency spectrum is generally free
of narrow lines (unlike the region below 100 Hz), but one disturbing feature is the presence of 
non-Gaussian broad disturbances that were not visible in O1. The infamous region around 1083 Hz 
is one example, as is the 100-200 Hz band.


Figures: [ER10 in red and O1 in black; labels are attached to peaks in the ER10 data]

Fig 1 - 0-1000 Hz
Fig 2 - 1000-2000 Hz
Fig 3 - 2-20 Hz
Fig 4 - 20-50 Hz
Fig 5 - 50-100 Hz
Fig 6 - 100-200 Hz
Fig 7 - 490-535 Hz 
Fig 8 - 1000-1000 Hz
Fig 9 - 1800-1900 Hz 

Other attachments:
* zipped file with full set of sub-band spectra
* Lines list with label definitions