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.

I was looking at the ALS-C_REFL_DC_BIAS output at the floor. The signal appeared on output 3 instead of 1 of the D-sub breakout panel. This was traced to a wiring error in the lsc model. Now corrected in the model, but not recompiled yet. This output has been connected to the second input of the common mode board and is operational. When the lsc model gets recompiled, the signal needs to be reconnected to output 1. The corner ALS overview screen has been updated to show the new filter modules.

The 27kHz line in the green locking was from the polarization controller, as Bram suggested.  Attached are plots of the PLL and PDH error signals with the MPC powered on and off.  

There is also a wandering feature in both signals that goes away when the MC is unlocked.  

Again this afternoon the single shot cavity alignment was good, but the dither alignment kept arriving at an alignment where the cavity axis was different from the single shot beam.  

First attempt failed.

• First input/output matrix was put in place by Jax.
• WFS demod dark offset was set.
• Briefly closed the servo and things didn't make sense.
  • WFSA error was zeroed but WFSB not. Cavity was apparently misaligned.
  • Even without the servo, I couldn't flip the sign of WFSB error by tilting ETM and/or ITM.

OL whitening.

See Thomas's entry. ITMX and ETMX are good now.

Demod phase and sensing nonsense.

After Thomas was done with OL, we had to measure sensing matrix again as it uses OL data. Found that demod phase changed, not reliable from measurement to measurement. In the end, I've found that:

• WFS demod phase and the sensing matrix is highly dependent on the cavity alignment or the WFS centering or both.
• I needed to  align the cavity by hand really well and center the WFS to obtain a reliable demod phase.
  • Even then, it looked as if the amplitude of sensing matrix elements varied by maybe a factor of 1.5 or more over 10 minutes time.
• WFSB beam position moves more than WFSA.

The measurement was done by wiggling ETMX at 3.5Hz and ITMX at 1Hz, first in YAW, measuring the demod phase and the sensing matrix for segment 1 and 3, then switch to PIT for 2 and 4. Angle to length shouldn't be a problem as PDH should have a large gain there to squash the length error.

New sensing matrix.

The attached shows one snapshot of demod phase itself on the left screen and the demod phase/sensing matrix measurement on the right.

Two dtt sessions show PIT and YAW. In each dtt window, left is ITM and right is ETM, top shows how Q phase is minimized, middle shows the sensing matrix amplitude in cts/urad (WFS/oplev), bottom shows the sensing matrix phase (should be 0 or +-180) as well as relative phase between diagonal elements (should be +-180).

The sensing matrix phsae still has 10 deg-ish systematic at 1Hz (ITM) and 25 deg-ish at 3.5Hz (ETM). Maybe a decimation filter for OL DQ, maybe something else, definitely not 1:10 whitening, I don't worry about this for now.

PIT.

YAW.

That was it for Friday. I will not work over the weekend at the site.