• Title: 10/21 OWL Shift: 23:00-7:00UTC (16:00-00:00PDT), all times posted in UTC
  

• State of H1: Observation Mode at 78Mpc for the last 15hrs
  

• Shift Summary: Locked my whole shift, more saturations than usual, microseism is still climbing to dangerous levels, no CW inj.

• Incoming Operator: Jeff B

• Saturation Log:

• ETMY: 23:59, 00:14, 00:57, 01:05, 03:41, 04:33, 04:36, 05:42, 05:45, 06:08, 06:29, 06:59
• OMC DCPD: 03:41

Observing @ 78Mpc, locked for 12 hours

LLO is up

Environment calm

Handful of glitches

Kyle will report more but here is a plot of pressure for the last 4 hours. We are not sure how permanent this "fix" might be but the magnitude of recovery suggests that this is the dominant or only leak in this volume.

Kyle, John 

Today we applied Apiezon Q putty to that portion of the leak region that we could access, i.e. 2" of seam weld+stitch weld behind the support gusset and 2" of seam weld+stitch weld on the opposite side of the stiffener ring (not blocked by the gusset).  Basically the known region of the leak site minus the inaccessible space between the stiffener ring and the spool wall -> No change in Y-mid pressure.  

Kyle

After lunch, I wet the entire region with Isopropyl alcohol -> no change -> Next, I removed the Apiezon Q putty using various scrapers and wire brushes and then used opposite facing wedges to compress a silicone rubber mat against a cut "feature" (that Gerardo had noticed yesterday which is just below the seam weld behind the support gusset and which is ~1.25" away from the stiffener ring) and the support stand.  The Y-mid pressure began to respond.  This cut had been covered by the putty and should have been sealed.

Kyle, Gerardo, John, Bubba 

We removed the silicone rubber mat but the pressure continued to drop -> We sprayed the entire area with Isopropyl alcohol and the pressure continued to drop -> We wet the region with Acetone and the pressure continued to drop -> We applied VACSEAL (SPI #5052-AB, Lot 1180402) to the cut and the pressure continued to drop 

CONCLUSION: 
It may be that the compressed rubber mat was more effective at getting remnants of the initial putty applied into the deep cut feature than was John and I's initial attempt using rigid flat tools.  Another possibility is that the brushes used to remove the putty may have embed putty more effectively into the leak.  Phase-change freezing of the initially applied alcohol is another possibility except that the leak stayed plugged for longer than the alcohol would have stayed frozen.  

At this point, I think that we can say that the leak is at the cut in the spool wall.  How permanently it stays plugged will be a function of the interaction of all of the substances which were applied to it.

J. Kissel, for R. McCarthy, R. Schofield, V. Roma, J. Warner

This has came up recently after I'd asked Duncan Macleod to plot it on the summary pages, but I've found out today, through a grave vine of those mentioned above, that the vault STS2 is busted. It's under semi-active investigation, also by the team mentioned above, but I just want to make sure something is in the aLOG about it. See attached ASD demonstrating the badness.

Also for the record, I used a DTT template that lives in the SeiSVN,
/ligo/svncommon/SeiSVN/seismic/Common/Data/2014-01-31_0000UTC_GND_STS2_ASD.xml
with the calibrations originally from LHO aLOG 9727.

• Title: 10/21 Eve Shift: 23:00-7:00UTC (16:00-00:00PDT), all times posted in UTC
  

• State of H1: Observation Mode at 75Mpc for the last 7hrs
  

• Outgoing Operator: Travis

• Quick Summary: He seemed to have a good shift after the commissioners got things going again. Been locked since with a few measurements while LLO is down.

Title: 10/21 Day Shift 15:00-23:00 UTC (8:00-16:00 PST).  All times in UTC.

State of H1: Observing

Shift Summary: Commissioners were mid-relocking when I arrived this morning.  After some hunting down of alignment changes of the IMs, and accepting them in SDF, in addition to letting violin modes rings down, the H1 locked without much of a problem.  It has been locked for 7 hours now.  Microseism is trending upwards, but wind is calm. 

Incoming operator: TJ

Activity log:

15:30 Sheila and Kiwamu to LVEA to turn on PZT driver

16:27 Joe D to X arm for beam tube sealing

18:09 Kyle to MY leak hunting

19:30 Kyle back

20:13 Joe D back to X arm

20:33 Kyle to MY

21:22 Kyle done

21:38 Richard to roof deck

21:48 Kyle, Gerardo, John, and Bubba to MY

21:50 Richard off roof

22:11 Joe D done

22:44 Kyle, Gerardo, John, and Bubba back from MY

Observing Mode at 21:12 UTC.

We have a few piece of evidence that suggest that anthropegenic noise (probably trucks going to ERDF) couples to DARM through scattered light which is most likely hitting something that is attached to the ground in the corner station.

1. Our spectrum is more non-stationary between 100-200 Hz durring times of high anthropegenic noise. Nairwita noted this by looking through summary pages (these glitches only seem to appear on weekdays between 7 am and 4pm local (14-23UTC), and not on Hanford Fridays when anthropegenic noise is low), and Jordan confirmed this by making a few comparisons of high/low anthropegenic noise within lock stretches.  (alog 22594)
2. Corner station ground sensors are a good witness of these glitches.  HVETO shows this clearly (see page for October 14th for example).  Also, comparison of bandpassed DARM to several corner ground motion sensors and accelerometers show that glitches in DARM coincide with ground motion (for example see nutsinee's alog 22527)
3. The DARM spectragram at the time of these glitches show what looks like scattering arches from 1 Hz motion and a velocity of around 40 um second total path length change. alog 22523  Both this high velocity and the fact that the seismometers on the tables don't seem to witness this motion well suggest that something bolted to the ground is involved in the scattering. This velocity is probably too high for something bolted to the ground.
4. The scattering amplitude ratio (ration of scattered amplitude to DC readout light on DCPDs) we would estimate bassed on the fringes in DARM 1e-5, similar to what we got in April  Using the ISCT6 accelerometer to predict the velocity of the motion doesn't quite work out.
5. Annamaria and Roert did some PEM injections in the east bay, which showed a linear coupling to DARM.  Annamaria is still working on the data and trying to disentangle downconverion from the linear coupling, but if we assume that scattered light is responsible for the linear coupling the amplitude ratio is fairly consistent with what we got from the fringe wrapping when trucks go by.

On monday, Evan and I went to ISCT6 and listened to DARM and watched a spectrum while tapping and knocking on various things.  We couldn't get a response in DARM by tapping around ISCT6.  We tried knocking fairly hard on the table, the enclosure, tapping aggresively on all the periscope top mirrors, and several mounts on the table and nothing showed up.  We did see something in DARM at around 100 Hz when I tapped loudly on the light pipe, but this seemed like an excitation that is much louder than anything that would normaly happen.  Lastly we tried knocking on the chamber walls on the side of HAM6 near ISCT6, and this did make some low frequency noise in DARM.  Evan has the times of our tapping.

It might be worth revisiting the fringe wrapping measurements we made in April by driving the ISI, the OMC sus, and the OMs.  It may also be worth looking at some of the things done at LLO to look accoustic coupling through the HAM5 bellow (19450 and 

19846)

Out of Observing Mode for jitter measurements while LLO is down.

Received a verbal GRB alert at 19:00 UTC.  Unfortunately, LLO was down at the time.

Keita, Evan, Hugh, Kiwamu,

When clearing the SDF differences, we noticed that the pitch bias offset of IM1, 2 and 3 are very different from the past (by ~ 1000 urad). These new offsets are the results of an alignment recovery effort by Cheryl at around 2 pm PT yesterday.

We checked various trends to understand why IMs needed so much change in the bias, but no clue was found. In the end, we accepted the new IM alignments even though we do not understand why they had moved. See the attached for the SDF difference.

The recovery effort

It looks that yesterday Cheryl changed the bias of IM1, 2 and 3 in order to bring them back to a place where their OSEMs read the same alignment values. As written below, after the interferomter was fully locked in this morning, the relevant QPD signals indicated that the laser light hits the same postion in the HAM2 and HAM3 area. This means her alignment recovery really aligned the beam back to where it should be. Or, in other words, IMs really had moved during the power outage for some reason. We still do not know why IMs had moved.

QPDs do not indicate a significant change

We checked the IM4 trans and POP_B QPDs in full lock to see if there is a significant difference in the actual laser beam. It seems that they are back to where they were in the past. This means that the interferomter alignment is not significantly different from the past with the new IM alignment. Good.

Also we looked at the HAM2 ISI oplev. Even though the oplev beam was not centered, we did not see a major change in PIT and YAW signals. They are about the same as before the power outage within a 1 urad.

Note that since POP_A is a part of the ASC control loop, it stayed centered.

HEPI and ISI

With help from Hugh, we checked HAM2 HEPI and ISI to see if they are back to nominal. And they are the same as before except for two HEPI prignle modes. See the attached for a trend of HEPI position locations. The HP mode moved by 5e5 (nm?) and VP mode changed by 3.5e3 (nm?). We are not sure how significant these numbers are in terms of the ISI table alginement.

Note that since the pringle modes are not DC-controlled and therefore it is sort of natural that they did not come back to where they used to be.

The power outage of yesterday caused the EPICS IOC to not exit completely, so the instructions to restart the process did not work.  I logged in to the computer running the process and manually killed the dewpoint process.  At this point the instructions to restart (in the CDS wiki) worked.  Data is now being collected from the dewpoint sensors.

We have made it back to Observing Mode at 16:59 UTC.  The violin modes are a bit rung up, but they are coming down in their characteristically slow fashion.

Things that Jeff B and I have done:

Jeff was having difficulty locking the X arm in IR for inital alignment.   Jeff moved SR3 pit to bring witness and oplev back to where they were before the power outage (both indicated that it lost 1-2urad of pit in the outage) (Still could not lock X arm in IR)  Jeff re-ran the green WFS alignment, and moved PR3 by 0.5 urad in yaw.

checked all shutters to retore them to the way they were before the outage. (opened ISCT1 spare, IOT2L spare, and X end fiber.)  This uncovered an interesting bug, which is that if theX green beam shutter is open, and the fiber shutter is closed, opening the fiber shutter will close the green beam shutter.  In most other situations both of these shutters seem to work fine.  

After this the X arm locked.  Jeff went through the rest of inital alingment without incident until SRC align.  Since SR3 was closer to the alignment from before the outage, we re-engaged the cage servo, which was turned off earlier probably because SR3 had moved.  the SRC alignment was way off when we started the SRC align step and Jeff aligned by hand to get us close.  

We then were able to lock DRMI several times, but had difficulty engaging DRMI ASC as people described last night.  We tried doing things by hand, it seemed like we were OK engaging the MICH and INP1 loops, but PRC2 was a problem.  In august, Evan and I changed the input matrix for this loop to no longer use refl 45 (alog 20811.)  I found the old input matrix in the svn and tried it.  This worked once so I've reverted the matrix in the guardian. 

Input matrix for PRC2 since august 24th: refl91A-refl9IB

input matrix before august 24th and now: 

        # PRC2 REFLA45I - REFLA9I
        asc_intrix_pit['PRC2', 'REFL_A_RF45_I'] = asc_intrix_yaw['PRC2', 'REFL_A_RF45_I'] = 0.83
        asc_intrix_pit['PRC2', 'REFL_A_RF9_I'] = asc_intrix_yaw['PRC2', 'REFL_A_RF9_I'] = 0.5
        asc_intrix_pit['PRC2', 'REFL_B_RF9_I'] = asc_intrix_yaw['PRC2', 'REFL_B_RF9_I'] = 0.5
        asc_intrix_pit['PRC2', 'REFL_B_RF45_I'] = asc_intrix_yaw['PRC2', 'REFL_B_RF45_I'] = 0.83

This matrix gets reset in the full lock ASC engage states, so this is not a change to the full lock configuration.

After this change we made it past DRMI, to the point where DHARD WFS are engaged durring the CARM offset reduction.  The bounce and roll modes are rung up, we spent a few minutes damping them but probably moved on too soon and lost lock probably due to roll modes in the final stages of CARM offset reduction. 

During ER8, there was a calibration artifact around 508 Hz - a non-stationary peak with a width of about 5 Hz. The peak went away on Sep 14 16 UTC probably due to an update of the calibration filters which was documented in this alog. When re-calibrated data is produced, it's worth having a look at some of this ER8 time to check that the peak is removed.

I made a comparison spectrum a bit before and after the change of the filters (plot 1). The wide peak is removed and the violin modes that it covers (ETMY modes, maybe some others) appears. I did the same thing for a longer span of time, comparing Sep 11 and Oct 17 (plot 2). The artifact manifests itself also as an incoherence between GDS-CALIB_STRAIN and OMC-DCPD_SUM (plot 3). The only other frequency where these channels aren't coherent is at the DARM_CTRL calibration line at 37.3 Hz.

I've also made a spectrogram (plot 4) of the artifact. It has blobs of power every several seconds. The data now looks more even (plot 5), though it's more noisy because the calibration lines are lower.

Executive summary: 

 In regard to narrow lines, early O1 data resembles early ER8 data: a pervasive 16-Hz comb persists throughout the CW search band (below 2000 Hz); there is a notable 1-Hz comb below 100 Hz (0.5-Hz offset); and other sporadic combs persist.
 On the other hand, there are distinct improvements: noise floor is cleaner nearly everywhere and substantially lower in the 10-70 Hz band; non-linear upconversion around quad violin modes and harmonics is much reduced; some combs and isolated lines have disappeared; and the OMC alignment dither frequencies have moved out of the CW search band (hurray!).
 Oh the third hand, new artifacts have appeared or strengthened: a sporadic 8-Hz comb suspected before is confirmed; a 1-Hz comb (no offset) has emerged below 70 Hz; a broad bulge appears in the 1240-1270 Hz band.


Details: 

Using 104.5 hours of FScan-generated, Hann-windowed, 30-minute SFTs, I have gone through the first 2000 Hz of the DARM displacement spectrum (CW search band) to identify lines that could contaminate CW searches.
This study is very similar to prior studies of ER7 data and ER8 data, but since this is my first O1 report, I will repeat below some earlier findings.

Some sample displacement amplitude spectra are attached directly below, but more extensive sets of spectra are attached in zipped files. One set is for O1 sub-band spectra with labels (see code below), and one set is an overlay of early ER8 spectra (50 hours) and the early O1 spectra. As usual, the spectra look worse than they really are because single-bin lines (0.5 mHz wide) appear disproportionately wide in the graphics

A flat-file line list is attached with the same alphabetic coding as in the figures.

Findings:

 A 16-Hz comb pervades the entire 0-2000 Hz band (and well beyond, based on daily FScans)
 A typically much weaker and sporadic 8-Hz comb (odd harmonics) is also pervasive - previously suspected, now confirmed (all harmonics are labeled in figures, even when not visible)
 A 1-Hz comb with a 0.5-Hz offset is visible from 15.5 Hz to 78.5 Hz (slightly wider span than before)
 A new 1-Hz with zero offset is visible from 20.0 Hz to 68.0 Hz
 A 99.9989-Hz comb is visible to its 8th harmonic (was previously visible to its 13th harmonic)
 The 60-Hz power mains comb is visible to its 5th harmonic (was previously visible to its 9th harmonic)
 There is a sporadic comb-on-comb with 0.088425-Hz fine spacing that appears with limited spans in three places near harmonics of 77, 154 and 231 Hz (ambiguity in precise fundamental frequency)
 There is a 31.4149-Hz comb visible to its 2nd harmonic
 The OMC alignment dithers have been moved to above 2000 Hz (thanks!)
 Upconversion around the quad violin modes and their harmonics is much reduced, although the strengths of the higher harmonics themselves remain high. To be more specific, the fundamental and higher harmonics of the upconversion itself (integer harmonics) due to the fundamental violin harmonics are highly suppressed, while the higher harmonics of the violin modes themselves  (not integer harmonics)  remain high. 
 A number of previously seen combs are no longer apparent:  59.3155 Hz, 59.9392 Hz, 59.9954 Hz and 75.3 Hz
 A variety of single lines have disappeared, and new ones have appeared (see attached line list) 
 Compared to early ER8 data, the noise floor is slightly lower in most of the band and significantly lower in the 10-70 Hz band, but there is a significant new bulge in the 1240-1270 Hz band


Line label codes in figures:

b - Bounce mode (quad suspension)
r - Roll mode (quad suspension)
Q - Quad violin mode and harmonics
B - Beam splitter violin mode and harmonics
C - Calibration lines
M - Power mains (60 HZ)
s - 16-Hz comb
e - 8-Hz comb (odd harmonics)
O - 1-Hz comb (0.5-Hz offset)
o - 1-Hz comb (zero offset)
H - 99.9989-Hz comb
J - 31.4149-Hz comb
K - 0.088425-Hz comb
x - single line

Figure 1 - 0-2000 Hz (Early O1 data with line labels)
Figure 2 - 20-100 Hz sub-band (shows complexity of combs below ~70 Hz
Figure 3 - 1300-1400 Hz sub-band (shows how clean the noise floor is away from 8-Hz, 16-Hz lines at high frequencies
Figure 4 - 0-2000 Hz (Early ER8 and O1 data comparison, no labels)

Attachments:
* Zip file with miscellaneous sub-band spectra for early O1 data (with line labels)
* Zip file with sub-band spectra comparing early ER8 and early O1 data
* Flat-file list of lines marked on figures

WP 5489

I have update the violin mode filters in CAL CS in order to make them more accurate. This will impact on the calibration at sub-percent level at around 30 Hz.

Joe B pointed me out that the way my matlab script (alog 21322) handles violin's zpk was not ideal (i.e. I was implicitly assuming certain ordering in the zeros and poles in zpk data format). I corrected the script as was already done in Livingston (LLO alog 20512). This resulted in somewhat better accuracy for PUM in 1-100 Hz . The attached screenshots are the new filters and discrepancy between the full ss model and the installed discrete filters. Compared with the one I previously reported in alog 21322, the magnitude of PUM is now somewhat better. The magnitude of PUM at 30 Hz is now more accurate with a very small discrepancy of 0.08 % (which used to be 0.2 % discrepancy ), and it is also more accurate at 100 Hz with a small discrepancy of 0.65 % (which used to be 2.4 %). I do not expect any noticeable change in the binary range with this update.

I have installed the new filters and loaded the coefficients in CAL-CS.