The violin duet is still playing. Evan is trying some new filters soon. Should know more in a couple, but currently we still can't go to low noise. Otherwise, winds are not  bad, but useism is still high.

Evan, Jim W, Dave:

h1nds1 locked up this afternoon at 14:36PDT. Jim manually reset the computer around 19:00PDT, but monit failed to autostart the daqd process. I logged in as root and restarted monit, whereupon it correctly started daqd. We have seen this "monit at reboot time" failure before.

This initial problem occured at 14:36 PDT, a swapper page allocation failure. Details attached.

20 s oscillations seen in EX UIM drive and dHard pitch. Cause not immediately clear.

As Corey and Kiwmau noted, ETMY has 2 violin mode harmonics fairly close to each other (1008.45 and 1008.49).  ETMY MODE3 has been set up to damp the higher frequency one with a broad bandpass, a phase of +60 and a gain of +100 set in the guardian (FM1,3,4,10, total phase at 1008 is 82 degrees).  Cheryl looked at the DARM spectrum over some of the long locks recently, and it seems that with these settings the lower frequency one 1008.45 has slowly rung up.

The phase shifting filter modules also had 6 dB of gain, which cause some unintended saturations, so I edited them to have 0 dB of gain at 1008.45 Hz. We addded two stop bands to the filter bank, one for 1008.493 and one for 1008.45 Hz.

After some confusion, we have been able to slowly damp this with a positive gain and FM1,2,4,5 (the new notch) ,and 10 on.  This means a total phase of -75 degrees.  This is not ringing up any other modes that we can see so far. 

So for now:

The damping of both of these modes are commented out in the guardian, so it will only be damped if you engage one or the other by hand.

To damp 1008.49Hz use FM1 (broad bandpass at 1010), 3 (+60 degrees phase),4 (100dB), FM6 (to notch the 1008.45 mode), FM10 to notch 1009.6 mode and a positive gain

To damp 1008.45 use FM1,FM2 (-60 degrees) FM4, FM5 (to notch 1008.49Hz) and FM10 and a positive gain. 

We can make two different filters to damp these two modes simulateously in the future.  

Title: Ops Day Shift: 15:00-23:00UTC, 8:00-16:00PT, all times in UTC

H1 State: locked in ENGAGE_ISS_2ND_LOOP

Help: Sheila and Evan

Overview: H1 lost lock after violin 2nd harmonics rung up about 14 hours ago.  Kiwamu worked on it, then Sheila, and now Sheila and Evan.

Details: Violin 2nd harmonic at 1008.45 has been ringing up for a few days, and last night caused a lock loss.  There is a nearby peak at 1008.49. 

Day was spent working on filter gain and phase to lower peak - time consuming, and within the last 30 minutes, the peak is now coming down in amplitude.  Details in Sheila's alog.

ISI blend filters changed to 45mHz, which helped, given the useism.

No other issues to report.

Elli was here and used about 30 minutes of unlocked IFO time to complete her measurement.  She work from about 17:07-17:38UTC.

Evan, Sheila, Cheryl

We switched blend filters from 90 to 45 mHz in the last several minutes.  There were large glitches in green arm transmissions when I switched ETMX X direction and ETMY Y direction.  It seems like  ETMY direction switched something got misalinged (the Y arm green transmission dropped). Cheryl adjusted transmon Y to recover the build up.

If anyone from seismic is interested in figuring out why switching blends causes glitches, I started switching around 18:50 UTC and finished by 19:01 UTC on October 25.  

The microseims BLRMS is around  0.5 um/sec and the wind had been gusting up nearly up to 20mph over the last hour but is dying down now.  ALthough the arms got misalinged, the build ups are much more stable with 45 mHz blends in these conditions.

Ops Day Shift - 15:00-23:00UTC, 8:00-12:00PT, all times listed are UTC

H1: cannot get back to Low noise due to violin second harmonics around 1008Hz

Current Plans:

- Elli on her way in to do her measurement - takes about 30 minutes and she needs an unlocke IFO

- Sheila on her way in - she had me comment out the line that engages ETMY L2 MODE3 in the ISC Guardian, but suspects that that won't be enough to get back to Low Noise, so is driving in

Changes:

- ETMY L2 MODE3 in the ISC Guardian commented out, and I left a comment in the file that I did this today

Current state of ground motion:

- useism coming up again and upper data points are touching 1 on the seismic plot

- also some anthropogenic noise starting about one hour ago

TITLE:  10/25 OWL Shift:  07:00-15:00UTC (00:00-08:00PDT), all times posted in UTC     

STATE of H1:  ETMy violin mode issues.  H1 currently down.

Incoming Operator:  Cheryl

Support:  Kiwamu (drove onto site)

Quick Summary:  ETMy violin mode (2nd harmonic) has been ringing up over last 2 days.

Shift Activities:

• ETMy Saturations:  8:00, 8:09, 8:37, 8:41, 9:25, 
• The main activity for today were the issues with the ETMy violin mode.  Over the last few days, it has been slowly ringing up and last night it reached a point to drastically affect H1 sensitivity & it will continue to do so until it is damped out.  Damping out violin modes is a slow-going process where one makes a subtle change (waits 20-30min) and then one watches to see if there has been an improvement. 
• I made a few gain changes to the ETMy MODE 3, but then H1 dropped out of lock.

Handing off H1 to Cheryl.  H1 should be able to get up to Engage ASC3 or DC Read out and then one can continue work on damping ETMy violin.  Cheryl will contact Sheila when she gets a chance.  She has experience working on damping these modes, but will give Sheila a call this morning.

Notable changes:

anti whitening (FM1) OFF for OMC DCPDs (A&B)....as Kiwamu notes.

ETMy MODE3 currently at gain of 50 (100 is what used to be nominal, but this rings up ETMy).

State:  Out of Observation Mode and at DC_READOUT for Violin Mode work.

As noted earlier, we had rung up violin modes.  Kiwamu is now on site.  We are pausing Guardian so we can address the ETMy 2nd order violin mode.  (was not sure what to mark this as with Observatory Mode....used Preventative Maintenance at first, but then switched to Corrective Maintenance.   We will stay here until we are able to bring down these huge violin modes.

• 9:25 OMC DCPD alarms begin
• 9:59 Went out of Observation Mode (since I saw LLO was out...they were running A2L to help L1)
  • At this point I was on phone with Kiwamu.  We determined we had a violin mode rung up, and ultimately found it to be ETMy's 2nd order mode (1008.45Hz).  We referenced Dan/Nutsinee/Evan's 2nd Order Violin Mode Table Alog 20345.
  • Started to address this.
  • When first alarms occurred, the range was fine, but as the violin mode rung up more, the range began to nosedive (from 80Mpc eventually down to 30Mpc).
  • We found that for ETMy, MODE3 was obviously noisy with HUGE outputs
• Started to look at ETMy.  Changed gain to try and bring down violin mode (gain started at 100, I took to 50 and saw no effect.  I went to -100, and H1 broke lock.).  While doing this, Kiwamu said he was going to come in.
• 10:41 Lockloss

Note:  at the beginning I trended a channel which was red in the ODC Overview (H1:0MC-DCPD_A_INMON) & over the last day, these dcpds have been noticeably getting big during the last two locks (starting at 10/24 11:00 utc).  See attached plot for these PDs getting rung up (presumeably due to the ETMy violin).

The DMT Viewer sessions (for seismic trends) on NUC5 had been closing out the last few days.  The NUC5 instructions say this is probably due to memory loss, so rebooted the computer by clicking the button on the nuc computer.  

Unfortunately, I didn't obviously see the computer come up on the TVs.   Luckily Jim was here and tinkered with the TVs and saw that the TV switched to a different input source.  So, had to switch it to HDMI (also had to switch the upper TV, which required a ladder).  

I couldn't log in to the computer, so I had to pull a keyboard and mouse from another computer & logged in.  (after this I could share the screen remotely).

I opened up the seismic DMT sessions.  I wasn't sure how to open the rf45 session (Cheryl posted the link to that file...but do I need to ssh into a different session to run this?).

Final note:  I could not get the mouse onto the bottom TV screen.

Chris B, Joe B

After LLO had locked again, Joe and I took the opportunity to perform the coherent stochastic injection. CW injections were off at both sites. And the intent bit was off at both sites.

For the LLO couterpart aLog entry see: LLO aLog 21999.

Waveform:

The waveforms injected were: https://daqsvn.ligo-la.caltech.edu/svn/injection/hwinj/Details/stoch/Waveform/SBER8V3.txt

Injection:

At H1 Chris performed the injection with the command:
awgstream H1:CAL-INJ_TRANSIENT_EXC 16384 SBER8V3_H1.txt 1.0 1129673117 -d -d  > log_stoch.txt

I've attached the log.

As we were doing the injection we noticed a range drop of ~10%.

IMPORTANT ACTION ITEM:

The end of the stochastic waveform was not tapered. So when the injection ended it introduced a large transient into the ETMY. Robot voice was activated. This needs to be fixed. The beginning was properly tapered.

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