Attempted to bring the interferometer back to 40W in an attempt to leave it at 40W over night.

- Slightly tweaked the yaw offsets of the QPDs to improve the PR gain, but ran out of patiance at a recycling gain of 28 - I think there is more to be had with better alignment..

 (The offsets I used were in the control filter modules: H1:ASC-DSOFT_Y_OFFSET=0.08, H1:ASC-CSOFT_Y_OFFSET=0.04)

- Then the OMC DCPDs started saturating - for now I just turned off the PD whitening.

- Added the input matrix from alog  to Guardian - but Guardian still does not turn the SRC1 loop on when it gets there.:

for SRC1_P:
AS_A_RF36_I : -0.5
AS_B_RF36_I : +1.0

for SRC1_Y:
AS_A_RF36_I : -1.5
AS_B_RF36_I : +0.34

However, the soft loops ran away several times during powerup - not sure what changed.

SUMMARY:  Had the Control Room to myself in the evening.  Unfortunately, H1 was a bit finicky (see Locking & Initial Alignment notes below) & drove me crazy for an hour or two, but eventually it went to 20W.  Will probably leave it here for the night.  Violin modes (& harmonics) are rung up.

Config Changes noted for EY on the CDS Overview:

ISI:  If we want to address this with reboot, take ISI to a non-sensor correction state first.  Then load new filters.  But can leave until the morning for Jim to take care of this.

Commissioning:

Soft Loop investigations at the beginning of the shift. (Jenne, Sheila)

Locking Notes:

Switched the input matrix values back for the TMS Soft Loops which Sheila alogged about earlier.  Tried locking, but DRMI did not look good.

Initial Alignment Notes:

Went through a couple of alignments and both times had issues with INPUT_ALIGN.  For the first time, the MC would not hold lock (so I skipped it).  For the second time, the Xarm flashes were good, but it would not lock.  I doubled the XARM gain, but I couldn't drop it back down without the Xarm breaking lock (aligned while keeping the gain at the doubled value of ~0.15).  Then moved on.

After the first Initial Alignment, could not make it past LOCKING_ALS.  Eventually went for the 2nd Initial Alignment (& had INPUT_ALIGN issue noted above, but atleast made it through the step).  Went for locking and this time had none of the LOCKING_ALS issues!

[Puzzled about what the deal is with INPUT_ALIGN!  Atleast in my attempts, it seemed to definitely affect whether I could get past LOCKING_ALS.]

Leaving H1 at the INCREASE_POWER (@20W) Guardian state for the night.

We measured the ASC PIT Sensing matrix in the REFL sensors.

We drove cHard, cSoft, Inp1, PRC1, & PRC2 loops at around 8 Hz and then took data of the CHARD and REFL WFS signals. We started at 1150766030 and stopped at 1150766330. Coherence was > 0.98 for all elements of the matrix. But why? What's the point of all this? Well, we are trying to make a clean CHARD signal by mixing the REFL WFS signals. However, we have 5 DOFs that show up in REFL, but only 4 sensors.

Therefore this problem is not a pure matrix inverse. Moreover, we would like to maximize the SNR of CHARD in the CHARD_IN1 so as to reduce the CHARD controls noise injected into DARM. IF the REFL signals all had the same noise performance or if they were uncorrelated with each other, this would not be a problem.

The first attached image shows the spectra and coherence during the sensing matrix drive time.

The second image shows the co-Herence during the ~20 Mpc stretch from around 1 PM today. Of course, the ASC noise was really bad then, but its sort of always is, so...

A more complete alog is coming later, but we have an expirimental ASC input matrix for the soft loops in the guardian right now, which is insenstitve to the hard loops.  We need to work on decoupling common and differential for this matrix to work.  You can revert to the old matrix by on lines 1950 in the ISC_LOCK guardian if necessary. 

Conor, Jeff, Jim, Krishna

After generating a model that can do offline sensor correction, I played around with the plant inversion, unit conversion, and high-pass filtering in the BRS sensor correction path.

Two major points became apparent: 
1) The BRS plan inversion is effectively providing some noise gain below 8mHz. By moving the poles in this filter close to the high-Q zero, a free 10dB can be won at low (f<5mHz) frequencies.

2) To improve correction at 10mHz, the STS2 needs some plant inversion. Instead, we can AC-couple the BRS at the same frequency and Q as the STS2. This means moving the poles 
in the filter 'GND_SENSCOR_ETMY_STS_Y_ROTVEL' FM3 until they match the STS2. The manual says 8.33mHz, Q = 0.707, but I found better subtraction performance with 7mHz, Q = 0.7. 
I had to push the pole in FM1 'acc_to_vel' from 2mHz to 1mHz to avoid phase loss. Additionally, FM2 'match', is now -0.774, about 15% lower than before.

These changes make some small gains at low frequencies, for a total of about 4x RMS improvement at 1mHz. The offline sensor correction goes from the Blue to the Red traces 
in attachment 1 (BRS_sensor_correction.png). 

The coherence tells a nice story: Nearly all coherence is subtracted from 0.1Hz down to ~30mHz (where BRS sensor noise becomes significant). At higher frequencies, they remain as 
coherent as before since the wind drives translation as well as tilt, and we're only subtracting tilt. At low-f, the GND sensor is dominated by BRS noise and they become coherent again.

Sensor correction was trained using 5 hours of consistent wind (attachment 3) GPS time: 1150459291  -- 20 June 2016 ~17:01 UTC

Stefan, Kiwamu,

With Keita's instruction in hand (27931), we have closed the 2nd and 3rd ISS loops at the same time. We confirmed that the 3rd loop still suppresses the arm transmission signals.

A next challenge will be to power up the PSL power with both loops closed.

The first attachment is a measured transfer function of the 3rd loop when the 2nd loop was closed. The PSL was set to 20 W. Note that we accidentally had a wrong sign for the control gain in this measurement, so the phase should be read with an extra 180 deg added. As expected the transfer function looks identical to what Keita measured before without the 2nd loop (27898). The second attachment shows the setting we used to close the 3rd loop. As suggested by Keita, we took out FM9. A good gain was found to be 60 dB larger than it was for the 3rd-loop-only configuration. The sign of the gain needed to be negative. We tried closing the 2nd and 3rd loops twice today, one time without an issue, the other time we unlocked the interferometer seemingly due to DAC saturation for the 3rd loop. Once the loop is closed the DAC counts for the 3rd loop is roughly 1000 cnts level -- no problem at all from the range perspective so far.

We then did one quick test where we stepped up the PSL power just by 1 W (i.e. 20 -> 21 W) to see how the ISS system reacts against it. This unlocked the interferometer; seemingly the second loop unlocked first by hitting the trigger upper threshold which subsequently unlocked the first loop whose diffraction power went up to 40 % on a time scale of a couple of seconds.

Nutsinee, Jim, Dave:

The HWS code crashed at 07:50 PDT this morning, Nutsinee tried to restart at 11:46 PDT, but it failed. We found that the 1TB raid is 100% full (has data back to December 2014). We are contacting Aidan to see how to proceed.

BTW: the /data file system on h1hwsmsr is NFS mounted at the end stations, so no HWS camera information is being recorded at the moment.

[Jenne, Sheila]

We spent much of the evening trying to find a better combination of QPDs to use for the SOFT error signals, since SOFT is what is moving, and pulling down our recycling gain.

In the past, we have chosen combinations that are insensitive to TransMon pitch and yaw, so that we don't put TransMon motion back into our arms. 

One of the things we tried tonight was to instead chose a combination for SOFT that was insensitive to HARD. Unfortunately, our HARD and SOFT modes are very nearly degenerate in the QPDs, so that turns out to have been a poor idea.  We were able to close the loops around this combination (before we realized that it wasn't going to be great), and I moved the SOFT offsets around to recover our power recycling gain.  In the screenshot, you can see that when we increased the PSL power, we lost recycling gain.  Then, it comes back. (Also shown is my stray click on the PSL guardian screen where I accidentally requested more than 50W. We kept lock during that adventure).

We tried once to create a combination that is maximally sensitive to SOFT (which will also be very sensitive to HARD).  We engaged the pitch loops with this combo, and lost recycling gain, and then lost lock.  So, more work to be done here.

We're still not sure what is the best combo to use - there are more things in this department to try out.

Quiet shift environmentally, and the entire shift was devoted to Commissioning work.  Here are a few notes:

• nds1 went down (Dave, Jim brought it back)
• Always make sure the Down Script runs---> after a lockloss noticed that the X-arm was misaligned by alot (tracked down to ITMx pitch).  Apparently, the DOWN script didn't clear the ITMx Pit M0 path.  Running DOWN & INIT brought back ITMx.
• Mysterious Arm dark offset zeroing was another oddity.

Untimately we need to engate the 2nd and the 3rd ISS loop at the same time. Toward this goal, I first tried to engage the 2nd loop but without the 3rd loop, and measure the 3rd loop open loop transfer function while the 3rd loop was open, but the IFO didn't cooperate at 20W today.

I instead measured the 1st loop and the second loop sensing by injecting into the 1st loop error point via the second loop board while the input side of the 2nd and the 3rd loop were both open.  I measured between 6Hz and 0.4Hz, and it was mostly flat as it should be. At 2W, the ratio of the second loop sensing to that of the 1st loop sensing was:

Sens2(2W)/Sens1 = -0.4.

At P Watts, this will become -0.2*P.

Let's say that the 2nd loop works at 25 Watts with the same setting as in O1. And we already know that the 3rd loop (without 2nd loop) works with the 3rd loop filter gain of -1. A good starting point would be to engage the 2nd loop at 25 Watts without the 3rd loop, disable FM9 (boardComp) of the 3rd loop filter, set the gain to -1*(-0.2*25) = 5 and engage the 3rd loop.

The 3rd loop digital gain needs to be changed as the power goes up because the sensing for the second loop is not normalized by power. The analog gain control slider is downstream of the 3rd loop summation point and cannot be used as a poor man's power scaling for the sensing.

While locking this evening, Sheila noticed that while H1 was locked in DRMI & after it went through PREP_TR_CARM, the Arm Offsets were put at wrong values (which would have prevented us from FINDING IR for later locks).  

In Guardian, we basically take an average of 1sec of data of the IN1 signals & then this avg is entered as the offset (with a "-" sign).

[From the ISC_LOCK.py script]      

• # measure ARM offsets (This is not used for the signal in PREP TR CARM?!)
• myoffsets=cdu.avg(1,['LSC-TR_X_QPD_B_SUM_IN1','LSC-TR_Y_QPD_B_SUM_IN1'])
• ezca['LSC-TR_X_QPD_B_SUM_OFFSET']=-myoffsets[0]
• ezca['LSC-TR_Y_QPD_B_SUM_OFFSET']=-myoffsets[1]

This sounds like it makes sense, but for our lockloss, Guardian took BOTH offsets to 0.0  (and the IN1 signals were clearly not 0.0).  So this looks rather dubious.  Attached is 6-seconds of data for both X&Y arms.

After the OAF model wiring fix, the Suspoint -> IFO-basis appears to work fine, except for the (already mentioned) limited subtraction.

I compared the GS13 (Suspoint) DARM with H1:CAL-DELTAL_EXTERNAL_DQ. To do this, I had to de-whiten the DELTA-L signal with 6 zeroes at 30 Hz 
and 6 poles at 0.3Hz (10^12 dewhitening). In principle, this should be calibrated down to 10mHz (the calibration model has a pole at 10mHz 
instead of DC). 

The two spectra (attachment 1, 'DARM_suspoint_vs_IFO.png') somewhat agree. There seems to be some residual error in the calibration of 
Delta L at low frequencies (it should cross 10^-6m/rt(Hz) at some point). Kiwamu found that the gain field of H1CAL-CS_DARM_FE_ETMY_L1_LOCK_L 
was a factor of 3 different from its equivalent suspension model, and corrected it, but this cannot explain the difference we see. 
The coherence (attachment 2) is quite good from ~0.03-0.3Hz.

Note that the GS13s are calibrated only to 30mHz, but this is also where they begin to rapidly lose coherence anyway. GS13 noise floor 
(for a single device) is added to show that there is some significant SNR at nearly all frequencies shown.

The ITMX PI path was measured during maintenance day driving from CDS and measuriung the quadrant outputs to the ESD. WP#5931
Specifically driving H1:SUS-ITMX_PI_OMC_DAMP_MODE1_DAMP_EXC with 80k counts, and measuring P2-P5 of D1600122 directly with an SR785.
In this case a splitter was created and used to allow the cable and ESD load to be included in the measurement.  This configuration resulted in a 1.6% drop in drive amplitude of the LL quadrant fairly uniformly across all frequencies.

There is some confusion with the channel naming, on the chassis front panel left and right are switched relative to the model naming.  The model names appear consistent with wiring diagram D1500464.
Otherwise these channels behave well.  

Since the calibration for the rotation stage doesnt seem to last too long, I added a bootstrapping method from rs_power_control.py (that I think Jamie made?)

At the end of the RS move, the bootstrap will move (requested_power^2) / (current power) further. This assumes that it is already close.

We tried it once going from 9.2W to a request of 20W and it went to 20.0W. Very nice.

Nergis, Peter, Stefan,

Currently, as we transition from 10W to 57W input power, our recycling gain drops from about 34 to 27. It seems like we need to tune the common TCS:

Attached are 3 plots:

Plot 1: DC signals:

PR_GAIN and normalized arm power (both blue)
AS_DC A and B (green and red)
POP_DC A and B (cyan and purple)
REFL_DC A and B (yellow and black)

Note the interesting behaviour of the REFL DC, all while AS_DC is linear in power.

Plot 2:

Arm and power recycling cavity powers, as well as test mass pitch control signals. The test masses have to compensate for radiation pressure, making the pitch control signal proportional to the arm cavity power.

Plot 3: RF signals:

Power and signal recycling cavity sideband buildups.

This is a quick summary of today's TCS joy. I ran another differential lensing test today. I went to the other side of the differential lensing (CO2X goes higher power).

The highest cavity pole was 352 Hz in this test.

• CO2 X 500 mW --> 700 mW --> 500 mW
• CO2 Y 230 mW --> 80 mW --> 230 mW

This time, I also took many measurements of the intensity and frequency noise couplings periodically throughout the test using Evan's automated measurement script (20470). I will analyze and post them later. The second attachment is trend of some relevant channels.