Have posted two sets of plots; one is with no zoom and the other with zoom in on ITMX and BS. The four peaks on ITMX has some time correlation with the peaks on ITMY and ETMY. The time of the second peak on the BS correlates with the third peak on ITMX. There is no clear pattern with the peaks on all 7 OpLevs being plotted. Will discuss with the OpLev folks.  

   These plots are run with minute trends not second trends, due to an error with plotting the second trend data. I an looking into the cause of this error.   

Laser Status: 
SysStat is good
Output power is 32.3 W (should be around 30 W)
FRONTEND WATCH is Green
HPO WATCH is Red

PMC:
It has been locked 0 day, 15 hr 14 minutes (should be days/weeks)
Reflected power is 2.0 Watts  and PowerSum = 24.9 Watts.
(Reflected Power should be <= 10% of PowerSum)

FSS:
It has been locked for 0 h and 17 min (should be days/weeks)
Threshold on transmitted photo-detector PD = 1.18V (should be 0.9V)

ISS:
The diffracted power is around 9.3% (should be 5-15%)
Last saturation event was 15 h and 17 minutes ago (should be days/weeks)

Coherences for last nigh lock are available here:

https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1109322016/

Here is my summary of the summary:

• No more coherence with BS ISI at low frequency
• Low frequency shows coherence mostly with MICH, SRCL and PRCL
• We still have the significant coherence with SRCL/PRCL at all frequencies, likely due to frequency/intensity noise. We'll have to try and tune the IMC longitudinal locking point soon
• There is large coherence at 967 - 974 Hz with ISI_HAM2_BLND_GS13RZ and ISI_HAM5_BLND_GS13RZ
• The 3 kHz bump, which is larger at the beginning of the lock and smaller close to the end, shows large coherence (basically 1) with IMC length control LSC-MCL_OUT. Maybe it's a gain peaking of the REFL servo?

The coherence of DARM with the BS ISI pitch sensor was no more present in last night lock, likely because Evan engaged the ISI second stage.

In the first attached plot, the red traces are with ISI stage2 on, blue traces off.

However, be aware that the alignment status of the IFO is likely different in the two locks, so we might have less coherence because of a better alignment.

The first attached figure shows a spectrogram of the DARM signal during last night lock. I had a look at one hour of data from 9.00 UTC.

The noise is highly non stationary almost everywhere. Looking at the longer spectrogram in the summary pages, it seems that the ~3 kHz bump got better later in the lock. However, I'm focusing at lower frequencies.

Scattered light

The second and third plots show a clear signature of scattered light arches, that contribute to the sensitivity quite often, and up to 120 Hz some times. I don't know what is causing them yet, but they're quite loud in the low frequency region, which is still relatively noisy.

Non stationarity in the hundred Hz region

The region between 50 and 500 Hz is very non stationary, see the 4th plot for a zoom in the spectrogram. To understand this I computed the BLRMS of DARM in the band between 130 and 160 Hz. There are a lot of quite fast excursions, probably glitch like.

I tried to correlate the BLRMS with angular signals. I could use both the ASC error signals or the local sensors of the optics (optical levers or shadow sensors). The 5th plot shows the result of the fit of local sensors (and their square) to the BLRMS. Altough I'm not able to properly reconstruct the largest BLRMS excursions, the trend seems quite explained by the angular motion. It's likely that when we have a larger than normal angular excursion, some highly non linear phenomenon create an increase of noise that I can't easily catch with my analysis.

I used a channel ranking algorithm to find out which angular motion is mostly rsponsible for the BLRMS variation. The algorithm is the same already used at LLO, with small improvements. The code is attached. basically, the algorithm starts with the BLRMS and fit every channel one by one to it. It selects the channel that gives the largest reduction in the residual error. It then moves on again, fitting the residual of the first fit again with every single channel, and select again the best one as before.

The result ranking, shown in the last attached picture, is that the most relevant motions seem to be: ETMY_YAW, SRM_PIT, SRM_YAW and BS_YAW. As a reminder, DHARD PIT has 3 hz bandwidth, while YAW is still low.

Reminder: Morning meetings are now on Monday, Tuesday, and Thursday at 8:30.

SEI:

• Looking at pump station power supplies, noisy pressure signal
• Stage 2 BS sensitive to rotations
• ISI in can in staging building, moving to LVEA on Thursday

SUS

• Betsy continuing work with SDF

CDS

• Pull racks in H2 building on Tuesday

3IFO

• Full speed ahead on all subsystems
• Jeff wants to bring a forklift around in the morning
• Betsy will turn off the cleanroom next to HAM 2/3 tomorrow

Vac

• The power supply next to HAM1 will be leaving
• Kyle will be working with BSC3
• Richard will be relocating vacuum cables

FMCS

• Over the weekend there was a temperature excursion at both end stations. The temperature dropped and will be monitored closely from now on.

OpLev

• The grouting project was a much larger task than previously anticipated, so they will test it on a single one first sometime in the future.

Tonight I spent some time on ASC during full lock.

In addition to the new and improved dETM pitch loop (LHO#17006), and the existing dETM yaw loop, I was able to close high bandwidth loops for ASB36Q → BS using FM2, FM3, and FM10 in MICH_P and MICH_Y. The gain is 0.1 for MICH_P and 0.3 for MICH_Y. [FM10 is a BS plant inversion which seems to still work pretty well. FM2+FM3 make the loop 1/f everywhere.] The BS yaw loop UGF was >1 Hz (when the gain was turned up to 0.7), and I suspect the pitch loop was similar.

With these high-bandwidth BS loops closed, I then requested the BS SEI guardian to take the ISI to FULLY_ISOLATED. We saw yesterday (LHO#17007) that turning on stage 2 of the BS ISI causes a transient in the BS yaw, thereby breaking DRMI lock. But with a high-bandwidth BS yaw loop closed tonight, the interferometer was able ride out this transient, with no excursion visibile in the BS oplev signals.

Then I turned off the BS oplevs (around 2015-03-02 8:45:30 UTC). This improved the DARM spectrum slightly from 8 Hz to 30 Hz or so.

After that, I moved ETMX in pitch and yaw until the cETM error signals were near their zero crossings. Then I closed the cETM loops as described in LHO#16931, but with gains of -1 for pitch and -0.2 for yaw. The lock broke before I got a chance to estimate the bandwidths. Adjusting cETM (and then closing the loops) brought the interferometer visibility up to 95%. However, the recycling gain remained slightly low, at 26 W/W. So there must be yet more loops to close in order to increase the recycling gain above 30 W/W.

model restarts logged for Sat 28/Feb/2015

no restarts reported. Conlog frequently changing channels report attached.

We made a few attempts to turn on the BS stage 2 loops after DRMI acquired lock this afternoon, both times DRMI became misalinged and we loct the lock.  We reset the CPS offsets and saw that the residual was small before turning on the loops, but still things became misalinged when we turned the loops on. 

Alexa, Evan, Gabriele, Sheila

We have closed 6 low bandwidth loops with DRMI locked with arms off resonance today, based on what we learned from talking to LLO yesterday:

INP1: REFLA9I-REFLB9I -> IM4 PIT and YAW

PRC2: REFLA45I-REFLA9I -> PR2 PIT only (YAW signal seems to have an offset)

SRC1: ASB36I-> SRM pit only, although error signal loks OK for Yaw as well

MICH: ASB 36Q -> BS, PIT and YAW

In the past we had phased AS36 to maximize the BS signal in Q, but we noticed today that the Q signal is contaminated by SRM.  We rephased AS B 36 to minimize the SRM signal in Q, this reduced the SRM pitch motion seen by AS36 B Q by 40 dB.  

We have not attempted to close the AS_C-> SR2 loop, since we are far off center on AS_C.  It seems that we will have to check search for the alignment that minimizes clipping on the Faraday and use picomotors to re-center AS_C,; we already know that we are clipping on AS_C when we are well aligned for the OMC PDs.  (alog 16831 ).  Despite this, it looked like ASB 36 I was a decent signal for SRM in both pitch and Yaw. 

Alexa, Gabriele, Sheila, Evan

Summary

We have updated the DHARD P filters so that we have a 3 Hz BW when we are on resonance. When we first engage the WFS at 50pm CARM offset, the loop is stable at 100mHz BW. This loop would also be stable at 3 Hz BW; however, we don't want to have to adjust the loop gain as we reduce the CARM offset, so we have left the loop at low BW at 50pm CARM offset. The DHARD Y filters are installed for a high BW configuration; however, they have not been tested yet.

Details for Pitch

The old DHARD P configuration was as follows: FM3 (0.1:0), FM4(:0.01), FM7(SB3.8), FM8(invDhP), FM9 (SB9.8), FM10 (ELP10),Gain = 8. Note: this is the inverse plant that Evan measured in LHO#16520.

The new DHARD P configuration is as follows: FM2(zpk([-1.5+i*4;-1.5-i*4;-3.5+i*1.5;-3.5-i*1.5],[-41+i*70;-41-i*70;-46+i*100;-46-i*100],160000)*gain(2)), FM4(:0.01), FM7(SB3.8), FM9 (SB9.8), Gain = 21. Evidently, we have removed Evan's plant inversion and replaced it with a compensation filter which we designed from Gabriele's model. The attached image shows the difference between the old and new configuration modulo the gains.  

At 50pm CARM offset, we were able to close this loop first with a gain of 21 (low BW), and then with a gain of 165 (3 Hz BW). Since the optical gain changes as we reduce the CARM offset, we decided to leave the loop at 50pm CARM offset with a low BW. Once we were on resonance, this loop was stable and gave us a 3 Hz BW as desired. This is in the guardian now.

Details for Yaw

The old/nominal DHARD Y configuration is as follows: FM3 (0.1:0), FM4(:0.01), FM7(SB3,14), FM8(invDhP), FM9 (SB9.8), FM10 (ELP10),Gain = 8. Note: this is the inverse plant that Evan measured in LHO#16566.

In preperation for a higher BW loop we have installed FM2 (same compenstation as for P), and FM6 (zpk([-0.376+i*15.215;-0.376-i*15.215;0.22+i*19.22;0.22-i*19.22], [-0.405+i*18.071;-0.405-i*18.071;-0.207+i*11.314;-0.207-i*11.314],1)gain(0.488863)). FM6 is designed to compenstate the resonant peaks between 1.5-3Hz in Gabriele's model LHO#17001 (this was confirmed by measurement). The second attached image shows the comparision between the nominal/old configuration and these new filters modulo the gains.

This loop has not been test yet. The guardian currently sets this to the old configuration.

The wind gusts are at around 30mph, we could see from the ALS control signals that the arms are moving more than usual, so I changed the end stations to the high blends and we are using BRS sensor correction at end X.  (configuration described in alog 16583)

Gabriele, Alexa

Gabriele had accidently unlocked the MC this morning, and had trouble relocking it. I know people had trouble with the MC yesterday morning, but there was no alog about this ... :(

The input power this morning was set to 5 W. When MC would try to acquire lock, the MC2 M3 LOCK L would reach the limit. I adjusted the input power to 2.8W and we locked immediatly. The IMC "DOWN" guardian adjusts the MC common mode board input gain depending on the input power (Power <4, 4 = 10); it's possible that the init and locked gain set for 5 W is not correct. This is something we new was not ideal, and we will correct. If you are having trouble locking the MC and the alignment looks good, I would suggest requesting the input power to 2.8 W and see if that works.  

Jim, Krishna, Ryan, Jeff, Sheila, Alexa, Evan, everyone

We have been having trouble keeping the Y arm locked with green, due to cavity motion of about 10 um in about 10 seconds.  The winds at end Y are approaching 40 mph, and have been climbing for an hour and a half.  We have copied the 90mHz blends for X and Y from the ETMX ISI into ETMY and blending high has allowed us to lock ALS for now.  

The attached screen shot shows the Y arm control signal (from the end station PDH with no slow feedback on) in beige, and the X arm in yellow.  The blends were switchd at about -21 minutes.