Seems like the green transmission is not on the same spot as last night, maybe the TMS moved.

We had some difficulty engaging the WFS because the whitening gains were all reset to 0dB and white/awhite were mismatched and Lock path for the ITM was off.

After these were fixed the WFS started working, today the transmission power doesn't go to 850 cts, it stays 750-800. 

I'm leaving WFS on for the night, and when Sheila is done she'll start the excitation for the ITM and ETM.

[Keita Jeff Arnaud]

Several measurements were taken on ETMX for top mass length to test mass pitch decoupling as well as for the pum tf inversion (cf Keita's aLog), and are summarized in the attached plot.

Page 1 and 2 : Top mass to test mass TF compared with the "fiber" model, length to pitch (p1), pitch to pitch (p2)
Page 3 and 4 : Pum to test mass TF compared with the "fiber" model, pitch to pitch (p3), yaw to yaw (p4)

Points with an uncertainty lower than 10% have been removed from the transfer functions.The data for the length to pitch (2nd page) is a combination of a swept sine measurement, and a white noise measurement.

Measurements slightly differs from the model, especially for the top mass pitch to test mass pitch (p2), thas has its first pitch mode shifted down. It would be interesting to plot those measurements against the correction that is beeing made to the current model.

The data for the pum pitch to test mass pitch doesn't have any coherence below 0.6Hz, and those points have been deleted because of a low uncertainty, so it is currently hard to do a fit with the few points we have. I would like to try few more times tomorrow to do this TF again.

In the meanwhile, I will use Keita's happyVecfit function to do the top mass fitting, and calculate -L2P/P2P

Yuta, Kiwamu, Daniel, Sheila, Dave, Evan, Stefan

After we had the PRMI drive properly balanced (alog 10559), we fine-tuned the 3f-locking again:
- Added a 60Hz (triggered) notch in MICH to reduce the RMS drive to BS and PRM.
- AC-coupled the PR2 drive at 2Hz - it was saturating at DC.
- Reset the REFLAIR_B_RF27: two stages of whitening, 27dB of whitening gain, digital gain of 1.
- With that the 3f lock by itself was fairly stable - lock duration was limited only by user impatience.

Next we brought up the green arm - for some reason ETMX-HEPI seems to have moved - we had to re-align both TMS and ETMX suspensions.
- After manually tweaking the green arm alignment the COMM_handoff worked fine.
- We parked the about 12kHz avaiy from resonance and locked PRMI.

- PRMI locking im this configuration seemed more difficult. Attached is a plot of the control outputs once locked - we were again frequently saturating the BS and PRM. 

- Ignoring all that we switched to 3f-locking, and brought the red on resonance - it stayed locked....


....



... but we don't understand the red build-up. It's wasn't any higher than single shot.... something aint right quite yet, but I need a beer.


EDIT (after the beer): The build-up actually makes perfect sense: The reflectivity sign flip of the ITMX due to arm resonance means the Michelson is exactly anti-resonant, redirecting all the light to the dark port. effectively no light gets back to the PRM. Hence the incident power on ITMX is equal to the (PRM misaligned) single shot power.

We also had rockIFO playing the PRCL signal while we put the arm on resonance, and couldn’t hear any rumbling.

To do next: measure length sensing matrix in PRMI and in state 3 (which we should lock on red using the 1f-signal).

I've been updating the MEDM screens to be sure that all the BSC-ISIs currently used are consistent with eachothers.

Right now, BS, ITMX, ITMY & ETMX have:

- the Start, Tstart and Tcrappy blends installed respectively in blend banks 1, 2 and 3

- a working controller (lvl3 on ITMX & ITMY, lvl2 on BS & ETMX)

- tilt decoupling on ST1 for all them, except BS.

Putting on the controllers with Tcrappy blends on all DOFs for ST1 and ST2 provide a robust configuration with good performance on all these ISIs.

In other words, everything looks good into the seismic world!

There is of course some room for improvement. We're currently in an aggressive configuration, sensitive to varation of the input motion. Adding tilt decoupling on stage2 will help pushing the performance. I'll work on that as soon as I have access to a platform.

One more pair of WHAM4 HEPI Actuators attached--NE(corner 4.)  Sure and steady's the word.

The BIO chassis that controls the ISC Whitening was shifted over from H2 without having its IP addresses shifted over, so it couldn't communicate with the rest of the slow controls system. Since we like being able to use the slow controls to control things, I changed the IP addresses from the H2 10.80.xx.xx convention to the H1 10.40.xx.xx convention. 

Greg, Mitchell,
Greg and I were able to attach the lift hook receiver onto the first 3IFO BSC. This is in preparation to transplant the ISI into it's long term storage home. 

Betsy & Jeff

   The glass optic was installed in H1-SR3. There were no problems or issues during the installation.

It was realized yesterday that TMS still had some "head-banger" hardware left from the cartridge install. This was removed today, which necessitated a rebalancing of St2. While working on this, I also looked at a CPS that was acting like it was broken. I poked around the cable for the CPS and it fixed itself, so I'm hoping it was just a loose connection. I'll look at this again tomorrow, but at this point it looks like the in-air cable MAY be bad. For now, I will be running TF's tonight. from OPSWS5.

J. Kissel

Following the same procedure outlined in LHO aLOGs 9453 and 9079, and similar to results from LHO aLOG 10493, with virtually the same demod parameters (only the amplitude was decreased from 1.25e5 to 1.2e5 [ct]) I balanced the coils on the UIM stage of H1 SUS ETMX. The final balanced gains in the L1_COILOUTF bank are
H1 SUS ETMX L1
Channel     Balanced COILOUTF Gain
 UL            -0.966
 LL            +1.004
 UR            +0.996
 LR            -1.034

The precision is still within +/- 0.5%; the ground motion while tuning the gains was not much better than yesterday, even though I tried several configurations of the ISI. See details of balanced vs. unbalanced signal SNR in comments below.

This balancing has reduced the L3 P and Y caused by a L1 pringle excitation at 4 [Hz] by
   DOF                  Reduction Factor @ 4.0 [Hz]
    P                          > 11.9      (peak below the noise, and totally incoherent)
    Y                          > 57.6      (peak below the noise, and totally incoherent)
The attachment shows the result from which these values were obtained, comparing the optical lever ASD at 4 [Hz] driven from L2 at the same amplitude for both balanced and unbalanced configurations.

Important note -- I found and was foiled by finding the L1_COILOUTF_UR gain sign set to
       Found   Expected
L1 UL    -        -
L1 LL    +        +
L1 UR    -        +
L1 LR    -        -
where expected comes from T1200015, and E1000617. Note these signs are exactly opposite from the PUM, because the UIM uses BOSEMs and the PUM uses AOSEMs, whose coils are wound in a different direction. Thus, the same magnet polarities are compensated by opposite signs.

I did a cursory check on the other three QUADs, and the same mistake is there too. This might just be a systematic, copy and paste error that we've propagated every where, and didn't notice until now because we haven't needed to use the UIM.

Kiwamu, Yuta, Stefan

We finished installing the inverse plant filters for PRM and BS. Compared to yesterday, we lowered the Q of the <1Hz to 5. This effectively adds some boost at the main pendulum resonance, bud hardly affects the cancellation above 2Hz.

Locking with the new filters required some reshuffling of limiters and boost filters. See snapchot.

We then added PRM feed-back to the MICH loop, driving it at 99 Hz and cancelling its signature in REFL_45_I.
We rescaled the BS gain (divided it by 16) to make the MICH output matrix the correct one from theory (1,-0.5). 
An updated all-included-snapshot is attached.

New OLG measurements are also included.

Attached are a screen shot of all relevant MEDM screens, as well as PRCL and MICH OLG measurements.

The LSC Guardian was updated to reflect these changes.

Inverse plant filters:
BS:
zpk([0.0382738+i*1.57475;0.0382738-i*1.57475;0.0647002+i*1.13667;0.0647002-i*1.13667;
    0.0420175+i*0.418069;0.0420175-i*0.418069],[0.0163157+i*1.54679;0.0163157-i*1.54679],1,"n")
zpk([],[0.5+i*0.866025;0.5-i*0.866025],1,"n")zpk([],[1250+i*4841.23;1250-i*4841.23],1,"n")

PRM:
zpk([0.130304+i*2.84281;0.130304-i*2.84281;0.092145+i*1.61388;0.092145-i*1.61388;
    0.0683932+i*0.680504;0.0683932-i*0.680504;37.2961],
    [0.139329+i*2.35023;0.139329-i*2.35023;9.53503+i*13.2475;9.53503-i*13.2475;3.58083;
    0.5+i*0.866025;0.5-i*0.866025],1,"n")


MICH roll-off filter (to avoid BS saturation):
zpk([-0+i*120;-0-i*120],[25+i*43.3013;25-i*43.3013;50+i*86.6025;50-i*86.6025;400],1,"n")

Jeff and Betsy will swap the glass optic into the SR3 suspension when Jeff gets back from end Y.

Alexa, Daniel, Sheila

We normalized the refl PDH error signal, and saw that we can stay in the linear range of this signal with only ALS COMM locked. 

We first normalized LSC-X_TR_A_LF by adding a gain of 0.000154 so that the tranmission peak is at roughly 1.  We set LSC-REFLBIAS to  REFL_A_RF9_I over the transmitted power (LSC-X_TR_A_LF).  The first screen shot is the PDH, the transmitted power, and the normalized error signal as we move the COMM VCO set frequency.  In the red trace we moved the frequency by 2kHz; meanwhile, in the blue trace we moved half as fast over 1kHz.  We used Alexa's equation from alog 7054  to roughly calibrate the signal: 80Hz cavity pole/150 counts pp of the PDH signal=0.533Hz/count.

We put this gain into the REFL_BIAS filter, we will do a more carefull calculation in the morning. With this calibrated error signal we were able to measure an out of loop spectrum of the noise between the arm cavity and the PSL.  Attached are some of the spectra that we took. In the top panel the green trace is a reference with the cleanroom over HAM1 on, in the red trace we turned the cleanroom off and Alexa tried to tune up the arm cavity alignment by maximizing the green transmitted power.  This realingment clearly helped at low frequecies, and reduced the coherence with the ETMX PIT oplev. 

The RMS we measured is completely dominated by low frequency noise that changed, probably because the alignment was drifting.  The RMS down to 0.1 Hz varied from 30Hz-70Hz, we also measured an RMS of 58Hz down to 0.01 Hz.

We saw coherence with the end station PDH reflected signal above 1kHz,  coherence with the PIT oplevs (mostly ETMX, which currently has level 2 controlers on Stage 1 and damping only on stage 2) around the PIT resonances (0.4-0.5 Hz), and coherence with YAW OpLevs from 0.04-0.5 Hz.  We also looked for coherence with some of Robert's PEM sensors, we have coherence from the periscope on ISCT1 from about 50-100Hz, as we kind of expected.

Tonight the noise is much worse than it was on saturday, the transmitted power was not stable at all over time.  This might be because we don't have as good of an alignment, or be because the arm cavity motion is larger because of the problems with ETMX ISI.  We also measured the spectrum with higher and lower gains in the COMM board, higher gain did not seem to help, which is different from the situation on saturday alog 10439 .