There is a large wandering peak in the IMC error signal.  (measured at Imon).  A movie is attached.  We tried several things to try to pin down where this comes from.  This wandering peak also shows up in the end station PLL and goes away when the IMC is unlocked.  

This afternoon I checked out some signals from the PSL to see if there were any similar wandering peaks in them and didn't see anything.  I looked on the TTFSS Field box mixr(in2) fastm test2, on the ISS Photodiode A output Photodiode B output. PMC mixer out. Unless there are better signals to look at, I would conclude this isn't from any of the PSL loops, but the IMC itself.  

Alexa and I also tried a few things to see if the wandering peak would go away under different conditions.  It does sometimes go away, but this seems unrelated to the things we tried.  We tried:

• turning off the ISS,
• turning off the slow feedback from the COMM PLL to the IMC VCO,
• turning off the COMM PLL,
• changing the gain on the FSS,
• unlocking the arm cavity,
• misalinging ETMX.  

We saw the wandering peak in each of these situations. We also had a look at Imon with the IMC unlocked, it wasn't clear what we were looking at when the mode cleaner was flashing.  We misalinged MC1 to look at the dark noise, and didn't see any wandering peak there. We also looked at the IMC open loop gain, there are no resonances or notches there, I remeasured several times and got the same result each time. (53kHz ugf 45 deg phase margin).

Alexa noticed that the UGF is higher than it used to be: she measured it in alog 10069 to be 28 kHz. The neither the settings on the MC board nor the transmitted power have changed.  

We have not been able to do the COMM handoff tonight, although the arm cavity and COMM PLL seem to be quite stable.  

We also attempted to measure the COMM PLL spectrum using the single shot green beam, to get a measurement of the laser frequency noise.  the beat note was about 10mV peak to peak (measured with 1MOhm impedance on the scope) which was not enough for us to lock the PLL. 

Fabrice and I did more testing on the HAM4 guardian today.   I've been lacking in posting, so I bit of recap.  Last week we started testing the ISI_HAMX guardian code on the HAM4 ISI:

USERAPPS/isi/common/guardian/ISI_HAM4.py

This links against the isi/common/guardian/isiguardianlib that Charles Celerier wrote.  A graph of the full system is included below.

The code has been behaving very well, but there have been a few discrepancies between the code and the desired mechanical behavior that we're ironing out.  As of today we were able to cycle through all the states without tripping the watchdogs.  Ultimately a couple of tweaks to the deisolation process did the trick.

It seemed that the shutting off of the ISO Boost_F filters was causing the isolation loops to saturate.  We fixed this by adding a 5 second ramp to all ISO Boost_* filters for all degrees of freedom.  Similarly, the ramp down of the isolation gains, which happens right after the boosts are shut off, was also happening too quickly.  This was particularly true when the platform location was far from the equilibrium position.  After a bit of trial and error we were able to survive the full deisolation process with 150um/urad offsets with a 20 second gain ramp to zero.  Preferably we'll come up with a more systematic way to set these ramp times down the line, but these should do for the moment.

Some additional comments:

The cart bias offsets are set right before reaching full isolation. However, the guardian reaches its fully isolated state (*_ISOLATED) before the platform location has reached it's final position.  I suggest the global guardian behavior would be more robust if the guardian does not transition to the full *_ISOLATED state until the platform reaches the desired location, within some tolerance.  This might be accomplished by tuning the loops to ramp slower to the desired offset and eliminate some of the ringing after the ramp.

We're getting a bunch of guardian notifications about ISO filter states during _RESTORYING_CART_BIAS_OFFSETS states.

Another day of testing and I think we're ready to stand up guardian nodes for HAM2 and HAM3 ISIs.

Fabrice, Hugh and I had a look at the arm cavity signals with sensor correction on and off this afternoon.  The arm cavity locking was not stable because there was no feedback to the top mass, (it turns out the PRMI guardian was reseting the XARM gain to 0).  Anyway, I learned something usefull....

With the sensor correction on, the ETM Stage 2 X drive is in phase with our refl controls signal as well as the slow feedback from the COMM PLL to the IMC VCO, using up about 1/4 of the range of each.  With the sensor correction off (Which Fabrice did by setting H1:ISI-ETMX_ST2_SENSORCOR_X_MATCH_GAIN to 0 from the normal setting of 1.15) this signal is greatly reduced, and we use less of the range of both VCOs.  However, the OPLev sees more pitch motion.  Fabrice says that we can also use a compromise sensor correction that would give less benefit in pitch and also introduce less longitudnal motion. 

Once Daniel and I got the top mass feedback going, the loops are all fine.  Our drive to the top mass clearly introduces pitch motion on the optic, so we need to diagonlaize the drive to the ETM, which Arnaud and Jeff agreed to help us with. 

Right now the arm cavity has been locked for about an hour, I will leave it that way for the night, with the alignment dithers, and top mass feedback on.  The COMM PLL automation is also running overnight. We have low winds (below 50th percentile) and low microseism tonight.

I also started a rudimentary LSC_XARM Guardian just to manage the feedback to the top mass, so we will not shoot ourselves in the foot as much in the future. It's not working yet, but coming soon.

Written by Yuta

Now that the mystery of the PD signal chain and the BS actuation efficiency for Michelson are solved (see alog #10213 and #10127), I corrected what we've found missing/wrong in the noise budget (NB) model.

[Motivation]
We wanted to check the validity of the NB model.


[What are missing/wrong?]
Things that were missing/wrong in the NB model "DRMI_Live.slx" copied from LLO was;

• The calibration for the suspension model was wrong
• Analog/Digital AI filters are not implemented
• Whitening gain values for PDs were missing (e.g. H1:LSC-REFLAIR_A_RF45_WHITEN_GAIN)
• Gains in the PD filter banks were missing (e.g. H1:LSC-REFLAIR_A_RF45_I_GAIN)
• Analog/Digital AA filters were wrong
• Choice of AIR and in-vac PDs were missing
• Optickle gives demodulated signal with the demod gain of 0.5. So, the factor of 2 was missing.
• The PD cable loss was not considered (I'm not sure how to treat with this kind of things in the Full IFO NB model)

[What files do I use?]
The NB model and functions for our Michelson lives in /ligo/svncommon/NbSVN/aligonoisebudget/trunk/MICH/H1. They are based on LLO DRMI NB model but corrected the things mentioned above.
The essential files are

run_NB.m: main script
make_MICH.m: function called from run_NB.m
./Params/paramNbH1MICHtest.m: parameter file
MICH_Live.slx: simulink model

They use the following Optickle files which live in /ligo/svncommon/IscCVS/iscmodeling/LentickleAligo/PRMI/ParamFiles for optical simulation.

optL1DRM.m: constructs Optickle model
probesH1DRM_00.m: puts probes for the Optickle model
paramH1MICH.m: parameter file


[Result]
Attached plot shows the comparison of the OLTF of the MICH loop from the measurement (see alog #10127) and from the NB model. They agree within ~20%. This error mainly comes from the power measurement error.

Note that the Matlab function "linmod" doesn't work correctly when the Optickle block is put in the NB simulink model. Do something like;

[systm,flexTfs] = linFlexTf('MICH_Live');
systm = prescale(systm,{freq(1) freq(end)});
systm = linFlexTfFold(systm,flexTfs);

to plot transfer functions (Thanks to Chris Wipf!).

Photos of the BSC10 Catridge installation are in ResourceSpace, here.

After painful trial and error process we've found a solution that converges.

• Demod phase and sensing matrix changed again. Rephasing and one DOF worked but not others.
• In the end we ditched the angle dither because it was very unreliable, and instead used length dither (see Stefan's alog).
• I stopped trying to obtain a nice input matrix that gives me hard and soft, instead started doing WFSA and WFSB based feedback because it's simpler. The output matrix still goes to hard and soft, and it worked.
• After phasing and manual alignment and  centering, engaged the servo one by one, centered WFSs. After some trial and errors and numerous freezeing workstations, we got something that converges.
• Linear range of the things is very narrow. Give things somewhat large offset and the servo ran away. Off-centering of 0.1 or so makes things much worse.
• Right now the bandwidth of things is small, probably UGF is smaller than 0.1Hz.
• We started trying to diagonalize the system, but after N reboots I had enough.

h1isiham3: Fabrice fixed h1isisham3, there was a new input port not grounded.

h1susitmy: is running a special trunk version with HWWD parts installed, will leave this model out of the upgrade

h1iscey: not spoken with the ISC group on this one yet

h1iopseib1: a real puzzler. the model has not been changed since 14 Nov, it compiled 16 Dec but wont compile on either 2.8.3 or 2.8.2 today. the H1.ipc file was changed, but this model receives the same IPC channel as h1iopseib2,3 and they compile fine. Comparing the models by eye shows no difference. I copied the Rx part from seib2 to seib1 and still b1 fails and b2 compiles. Will need to scratch our heads a little more. Perhaps a regeneration of H1.ipc from scratch is in order.

I noticed some cut-n-paste IPC errors in the h1asc model which needed resolving before we upgrade to rcg2.8.3.

1. IPC from h1asc to sus PR2,PR3 and PRM:  RFM parts instead of Dolphin (PCIE). These were done today, so it was easy to hand edit H1.ipc and remove these 6 parts from the end of the file. I then edited h1asc.mdl and replaced the RFM parts with PCIE parts.

2. IPC from ASC to SUSHTTS: Dolphin (PCIE) parts used instead of Shared Memory parts (SHMEM). Slightly more difficult to fix as subsequent PCIE parts have been added. I removed the ASC parts and shuffled the later parts down in index. Then changed h1asc.mdl to replace PCIE with SHMEM.

Finally using rcg2.8.3 I performed a "make h1asc" which populated H1.ipc with the correct ASC part types. I verified the additional parts were correctly indexed.

In preparation for an RCG upgrade to version 2.8.3 tomorrow morning I am recompiling (but not installing) all models against 2.8.3. Please do no make any model changes or builds for the remainder of today.

In detail:

/opt/rtcds/rtscore/advLigoRTS-2.8.3 is a new checkout of the tags/advLigoRTS-2.8.3 released by Rolf today

/opt/rtcds/rtscore/release relinked to 2.8.3

New build area created

/opt/rtcds/lho/h1/rtbuild-2.8.3 and release pointer relinked to it

inside of rtbuild-2.8.3 the advLigoRTS-2.8.3/configure script was ran.

No issue to report other than missing zippers on the SEI Ceiling Sock.

Clean room back up with the Cartridge ready to go down at lunch.  Torqued to Support Tubes and closed up by 1430pst.

Thanks to Apollo Scott, Mark & Bubba, SUS Travis and SEI Jim.

Corey helped too and took lots of photos.

ETMY Cartridge Install all day at EY

630 Cleaning crew working at EY

845 Filiberto installing HV supplies at EX

901 ETMY Cartridge being lifted

905 Jeff B adjusting dustmon at EY to provide better local alarms

1000-1200, 1300-1600 Jodi/Chris S working at MY

1107 Travis working on ITM at LVEA Test stand

1243-1500 Alexa working at EX

1245 Brief dust alarm in OSB optics lab....Joe Derenzis working in that area.

1315 Jax rummaging for hardware in Squeezer Bay

1427 Craig C working in H2 enclosure

After discovering that the MPC polarization controller creates a peak at 27kHz in the EX PLL noise spectrum, I decided to take some more measurements at the end station with the controller off.

PLL Servo Board

• Input 1 enable: ON
• Input 1 pol: NEG
• Input 1 gain: 0db (unless otherwise specified)
• Common Comp: ON
• Fast Option: ON
• Fast pol: POS
• Fast gain: -8dB
• Boost 1: ON/OFF

PDH Servo Board

• Input 1 enable: ON
• Input 1 pol: POS
• Input 1 gain: -7db (unless otherwise specified)
• Common Comp: ON
• Boost 1: ON
• Boost 2: ON/OFF

PLL error signal measured out of PFD IMON, and PDH error signal measured out of demod IMON.

The lowest RMS comes from the PLL Boost 1: OFF, and the PDH Boost 2: ON. With the PLL Boost 1 off there is no gain peaking and the the OLTF of the PLL is stable with a UGF of 22kHz and a phase margin of 50 deg. I need to take an OLTF with the PDH Boost 2 on.

[Evan, Yuta, Kiwamu]

We worked on the alignment automation this morning. We closed the PR2 pitch and yaw loops manually.

In order to have the excitation only on the bottom mass of PR2 while keeping the feedback on the top mass, we installed a high pass filter at the bottom drivealign matrix and installed a notch filter at the top stage LOCK_P and LOCK_Y.

I plan to add these channels to the DAQ during maintenance tomorrow and create an alarm handler for them.

The slow feedback kept causing large values of the IMC VCO set frequency, which causes an error for the VCO.  To get around this I turned up the UGF on the IMC VCO slow loop to 0.1Hz, and now the slow feed back gain (In COMM PLL screen) is set to 40000Hz/V.  This seems stable for as long as the cavity stays locked, which is currently a few minutes. I also updated the screen ALS_CUST_COMM_PLL.adl because of a mistake with the reset button.