• Initial alignment, since Yarm green looked bad, and lost lock at TRcarm.
  • Set dark offsets of POP_A_45.  Was unable to lock Xarm IR for initial alignment.
• Keep losing lock at the start of CARM_150pm
  • Undid Craig's addition of 3dB in IMC_IN1GAIN.  This was done by changing the new lacparams.IMC_IN1_gain from 28 to 25.
  • Big 1Hz osc in IR arm powers, but don't see it in green arm powers. 
  • Turning off REFLBIAS FMs 4, 10, which are turned on at the end of CARM_TO_TR, gets rid of this osc.  These reduce the low freq gain by 35dB.  These are currently commented out in guardian. (Later: moved them to RESONANCE, so they are engaged before transitioning to ANALOG_CARM)
  • But, we failed to make the transition to analog CARM. 
• ETMY SEI tripped, as did TMSY SUS, perhaps due to BRS work at the end station?
• New lock, moving the REFLBIAS FMs to RESONANCE state seems to have worked smoothly.
• Added code to PREP_DC_TRANSITION so that it will re-request the OMC to lock, if it didn't succeed. (Untested so far)
• New lock, after moving pitch SOFT and POP_A offsets.  DHARD_P rang up, needed to *lower* the gain to -30. Recall that in alog 44456 I had to *increase* the DHARD_P gain.  So, maybe the gain was always okay at -25ish, but we didn't have enough good buildup in the arrm at 20W?
• We were sitting in Close_Beam_Diverters (I had manual-ed there from LownoiseETMX_ESD), and lost lock due to likely human error.  But, the IFO didn't recognize the lockloss (which Craig also saw yesterday).  I looked, and there wasn't a Run state in Close_Beam_Diverters, so it wasn't checking for lockloss.  I have put in a  run state that just returns True, so that this state will now bring us to DOWN if we lose lock.

Injected a MICH or SRCL line at 45 Hz, tuned the MICH or SRCL feedforward gains to minimize the line in DARM.

Small improvement by changing MICH_FF_GAIN from -1 to -0.955. No improvement by chaning SRCL_FF_GAIN. Those gain changes have been absorbed into the Oct10 filter, so the nominal gains in the filter banks are still -1 and -1

The attached plot shows the effect of switching on the MICH and PRCL feedforward (beware that the reduction of the ~50 Hz / ~ 100 Hz bumps is due to closing the beam diverters)

While locked at 20W, we adjusted the soft offsets, the POP_A offsets and the SRM/SR2 angular position, trying to improve the carrier recycling gain. We did not get back all the build-up we could (the lock broke before we were done).

The realignment not only improves the recycling gain for the carrier, but also reduces the coupling of frequency noise at high frequency.

So part of the increase of frequency noise when we power up can be recovered by tuning the alignment set point.

We updated the soft offsets and the POP_A offset to the best value found so far:

caput H1:ASC-X_TR_A_PIT_INMON -0.168109
caput H1:ASC-X_TR_A_YAW_INMON -0.208626
caput H1:ASC-X_TR_B_PIT_INMON -0.021139
caput H1:ASC-X_TR_B_YAW_INMON -0.076330
caput H1:ASC-Y_TR_A_PIT_INMON -0.148733
caput H1:ASC-Y_TR_A_YAW_INMON 0.372014
caput H1:ASC-Y_TR_B_PIT_INMON 0.078767
caput H1:ASC-Y_TR_B_YAW_INMON 0.434853

Screenshot of error attached. Restarted computer. IOC did not reconnect to PLCs upon auto start at computer boot. Did after restarting the IOC manually.

This kind of error has been much more frequent at the end stations. This is the first time, at least in a long time, that I have seen it at the corner station.

During the low noise lock at 4:50 UTC today (Oct 11), there is a comb of lines in h(t) at 56.84 and multiples. They are quite narrow lines. The most interesting characteristic is that they have extreme amplitude modulation.

The first attachment is the h(t) spectrum with the lines marked. The second shows narrow BLRMS around each of the lines. The fundamental at 56.84 Hz has a half-period of about 24 minutes. The amplitude goes very close to zero, and looks very periodic. Each multiple n has zeros in the same place, but the period is n times shorter. Maybe this could be all generated from the fundamental with the right kind of nonlinearity. I'm not sure what would give such a slow but extreme modulation - maybe some centering servo?

The BRUCO results show a lot of channels at End-X coherent. Accelerometers on BSC9 seem to see it, but without amplitude modulation. PCal X sees it in the TX and RX PDs, but stronger in RX; but it doesn't seem anywhere near the level to get into h(t).

   While the commissioners were at JC and in a meeting, I ran the new clean HEA vacuum over the parts of the TCS-X table that were within reach. Very little water was extracted as most had evaporated during the past week. I did not vacuum under the periscope mount or along the back wall of the enclosure due to limited access. The enclosure panels were put back on and the laser restarted around 13:00PT. Per TJ's request, I left the left side door cracked and the fan on. TJ will finish closing up the table later today.    

The new Debian9 environment was missing the LIGO_RT_BCAST variable, which prevented diaggui and awggui from selecting EXC test point channels for excitation. I have opened an FRS for this

https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=11637

The problem has been fixed.

In addition to adding this environment variable, we also installed the pydotplus packaged needed for guardian graphing, and defined the 'z' alias to cdsutils.

Richard, Fil, Dave:

The Contec6464 binary card for h1susitmx was replaced. Procedure was:

• stop models
• power down h1susb123
• power off IO Chassis, swap BIO card, power up IO Chassis
• power up h1susb123*

* this did not boot on power up, it was stuck at the console message:

BMC IP:10.99.101.128

DXE--Intec Reference Code Execution

We waited for several minutes, then powered the chassis completely off by pulling the power cords. On reapplication of power the system booted and started the models. SWWDs had tripped on SEI by this time.

A second model restart was required after the binary input/ouput chassis were subsequently power cycled.

[Sheila, Haocun]

We began to work on guardian for squeezing automation.

- A new state "PREP_SQZ_ALIGN" was added in ALIGN_IFO. This locks OPO --> Misalign PR2, SR2; Align SRM --> open the beam diverter.

- 'SUS_SR2', 'SUS_PR2' and 'SQZ_LOCK' were added into the nodelist.

Daniel, Terry, Nutsinee

We temporary locked LO loop (with PSL LO) using additive offset on TTFSS just so we can figure out why is it so noisy (slow path still output to OPO PZT, fast goes to TTFSS AO). We saw 3MHz leaking out of PFD IMON and it also shows up in LO common mode board fast control signal. Some filters need fixing.

LO loop OLG transfer function shows UFG at 63kHz (without 4Hz/400Hz slow path compensation). Transfer function at fast path shows crossover ~700Hz (with 4Hz/400Hz). Within a factor of 2 of what we calculated.

With the original Pomona box (alog44446) we would've needed a gain of 36dB on the fast path for a reasonable cross over. Daniel doodly clipped a 220Ohm resister in parallel to the existing 1kHz to give us 14dB less gain in the slow output to PZT. This allow fast gain to be within +32dB slide bar range.

Craig, Sheila

We engaged the MICH and SRCL FF with the filters that Jenne and Gabriele loaded 44470.  There is some remaining coherence with MICH and SRCL, so our FF could be tuned.  There is a lot of noise due to CHARD up to 40 Hz.  We also have frequency noise above 1 kHz, we haven't boosted the CARM loop yet.  (see attachment)

The peaks we've seen the last 2 nights at 50Hz and harmonics went away when we closed the REFL and AS beam diverters.  

The calibration isn't done yet, but Craig did a spot check with PCAL at 90 Hz and it seems like the calibration there is not off by much.  We still have a lot of broadband noise from 45-150 Hz, we will wait until this is calibrated to make a comparison with the noise which appeared after the Montana EQ.  

The BRUCO scan that Gabriele ran had coherence with REFL 9 Q (which was plugged into I last night but is now fixed so that digital I is really I and digital Q is really Q) around 100 Hz.  This coherence is eliminated along with the peaks at by closing the beam diverters.  

We are leaving the interferometer alone to get at least 25 minutes of data with no one doing anything starting at 4:50 UTC Oct 11.  

DaveB is looking into it, but DTT isn't ramping down excitations using noise injection.  This is something we've been seeing, but usually it just causes saturations.  I think it *may* have caused a lockloss a week or so ago, but it definitely killed a lock today.

I attach an ndscope showing that the excitation just suddenly stops, as well as 2 screenshots showing my excitation and measurement settings.   You can see in the Measurements tab that I've got a rampdown time set for the excitation.

For now, since these are noise injections, I can use awggui for the injection, which doesn't seem to have these same ramp down problems.

I append these screenshots to FRS ticket 11367.

Terry, Nutsinee

There was an error in the previous mode matching solution that contributed to a miserable -23 dBm beat-note signal at the detector. The solution (attached) still gives a fairly miserable -16 dBm beat-note. However maintenance Tuesday finished before it was fully optimized and I was concerned about bumping into the HEPI by HAM6 now that ISCT6 is in its final position. There is also maybe an issue of saturation with .7mW from the Mephisto path and .5mW from the PSL path (detector should have a 1 mW max.) a change of beam-splitter should fix this if necessary.

To minimize squeezer down time from table work I intend to address this when we install the amplitude modulator (to measure the TF from pump modulation to OPO phase modulation), and replace the PSL table fiber (with APC) and add a motorized waveplate and flipper to SQZT6 (to replace the manual versions), probably Thursday.

Figure 1 shows coherence between the IMC DC WFS and DARM, with photos of the optic mounts that are producing the jitter peaks, based on this log: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=42551 . The Qs are fairly high so damping should help. One tool that would be useful, is a small tuned mass damper, variable across the 200-800 Hz band, that can easily attach to a U200-A mount with a little clamp or epoxy. A possible clamping scheme is visible in the picture on the bottom left of Figure 1: I have used two commercial spring clamps near the adjustment screws to broad-band damp (via the mass and the red rubber grips) the U200-A mount. The spectrum shows that this and other damping has reduced the Q relative to the other two mounts, but a tuned mass damper on a clamp like this might be useful on the other mounts and possibly on this one. The jitter spectrum also has some fairly high-Q U100-A mounts (see above log entry).

Figure-2 compares DARM, IMC DC WFSs, coherence and table motion for Monday night and for O2. This is a bit premature since DARM and the WFSs are not yet well calibrated, and so I can’t make a definitive comparison of jitter coupling. But in this preliminary look, the change seems consistent with the table motion reduction being the biggest factor. The ~344 Hz peak seems to be a lot lower, and the table motion has decreased by 5 or more in that band. But the 483 Hz peak is in a band where the table motion has not really decreased (it was already low in O2 in this band, compared to nearby bands) and the 483 Hz peak does not seem to have improved by much in DARM. But, again, this is a first look; calibrations to come.

The second page of Figure 2 includes accelerometer signals when the water was off, showing that we could still improve by a factor of a few in the band around 500 Hz. We are planning to improve some water circuits during the vent. It might also be possible to reduce some flow rates.

I wanted to try adding the "jel" packs that Arnaud and Eyal have been using at LLO (for instance, here ), because it seems to help the low frequency noise. Jason had some left from the oplevs (excess beyond 3IFO needs), so I tried adding some the ETMY BRS, see attached photo. In the process, I must have bumped the "mass adjuster" in the process, because when I checked the BRS status before leaving the end station, it was dead, out of range. So, I set about rebalancing, and found that the rdesktop program (which I had aliased) with the new zotac workstation was laggy and basically useless. After talking to Carlos, I tried using remmina, which was much better, but still laggier than rdesktop was on the old mac/debian workstations. When I left the BRS was still rung up and not ready to use, but was slowly settling down. With the low microseism, this shouldn't interfere with commissioning, so I don't want to risk trying to settle it by hand, yet. If it's still angry tomorrow, I can try soothing it.

TJ, TVo

Daniel suggested that we try swapping the cameras with any spares we have in order to see if the bad pixel problem goes away.  From the user manual, it is not clear what happens when a pixel "malfunctions' on the CCD so this may require some more testing.

TJ and I found two spare cameras in the cabinet, one is labeled SN 008 and the other is unlabeled.  The original installed camera for ITMX HWS was SN009.  We first installed the unlabeled camera and the noise was worse with more bad pixels, then we installed SN008 and saw that there were less bad pixels so we left that one in. 

The stationary (no transient heating) noise in the spherical power seems to have decreased with this new installation with the variance being about 3 udiopters over the course of half an hour (time series attached).  Also attached is a gradient plot overlapped with the raw CCD images with the plates on and off. There are one or two gradient vectors which stand out in the upper half of the images so it still behooves us to try and implement a bad pixel finder which eliminates these bad data points before going into the HWS code which fits the spherical power.