Mitchell, Jim,
This morning the pushers were removed and the final dog clamps installed. The only work that remains for the ETM-Y ACB is to route and plug in the cable. This work will be done with SEI cable clean up. All tools and hardware removed from the building.

Brett and Mark

The matlab parameter file quadopt_fiber.m has been updated on the svn with the values found from the H1ETMY fitting results.
The corresponding temporary file quadopt_fiber_H1ETMY.m has been removed.

The parameters have been moved by the following amounts:
---------------------------------------
mn: 0 g
Inx: -1.1168 %
Iny: 3.0445 %
Inz: -0.87769 %
Inxy: 0 kgm^2
Inyz: 0 kgm^2
Inzx: 0 kgm^2
hn: 0 mm
m1: 473 g
I1x: 4.0141 %
I1y: 12.3876 %
I1z: -0.087956 %
I1xy: 0 kgm^2
I1yz: 0 kgm^2
I1zx: 0 kgm^2
h1: 0 mm
m2: 43 g
I2x: -2.9363 %
I2y: 8.4274 %
I2z: -0.034308 %
I2xy: 0 kgm^2
I2yz: 0 kgm^2
I2zx: 0 kgm^2
h2: 0 mm
m3: 10 g
I3x: 2.1949 %
I3y: -8.9273 %
I3z: 0.70939 %
I3xy: 0 kgm^2
I3yz: 0 kgm^2
I3zx: 0 kgm^2
h3: 0 mm
ln: -0.183 mm
l1: -0.212 mm
l2: 9.121 mm
l3: 0 mm
rn: 0 mm
r1: 0 mm
r2: 0 mm
Yn: 0 %
Y1: 0 %
Y2: 0 %
su: 0 mm
si: 0 mm
sl: 0 mm
nn0: 0 mm
nn1: 0 mm
n0: 0 mm
n1: 0 mm
n2: 0 mm
n3: 0 mm
n4: 0 mm
n5: 0 mm
kcn: 1.0376 %
kc1: 1.091 %
kc2: 2.2895 %
kw3: 9.4232 %
kxn: 0 %
kx1: 0 %
kx2: 0 %
dm: 0 mm
dn: -0.22438 mm
d0: 0 mm
d1: 1.8536 mm
d2: 0 mm
d3: 0 mm
d4: -4.8596 mm
---------------------------------------

Note, the mass values were changed to the as-built values from H1 ETMY. The wire lengths changes are updated values found from the mathematica model, which is the origin of the matlab. Note that the pum wire length (l2) is within about 0.1 mm of that found from the model fitting code. All other values are from the model fitting. Ref https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=10089. The d4 change is probably not so large in reality because it can be distributed between d3 and a little bit of d2. The change in kw3 (fiber bounce stiffness) is likely due to the fact the the original value was from the LASTI fibers, which may not be exactly the same. The pitch inertias also changed a lot, which I cannot readily explain, but it could be there is some degeneracy with the updates in the d values.

There is still a mystery on the wire lengths, where the lengths the model requires as determined by the master mathematica model are different by a few mm from those we cut them to.
The context for this can be found in these previous log entries:
ETMY model fitting results - https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=10089
PUM wire length calculation - https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=10476

Jeff B., Andres, Kate

Yesterday, we took counts with a handheld particle counter outside the HAM4 chamber before removing the soft cover, and again in chamber. The counts were low, especially compared to the counts taken in February (see aLOG 9974). The battery on the counter was very low, and it may not have been working properly. 

The vertical wafer in front of SR2 (T1400195) was replaced with a new one. This will give us an idea of the contamination generated by door activity only. The table and suspension are not locked down, so the horizontal wafer in the center was not replaced. 

I re-measured BS and PRM actuation transfer functions in PRY configuration after plant inversion done on Mar 5 (see alog #10559).
It seems like we succeeded in BS and PRM balancing within ~8 % and MICH to PRCL coupling is expected to be supressed by factor of ~4, compared with using only BS as an actuator.
For the sensing matrix measurment, the effect of residual MICH to PRCL coupling gives ~6 % error for MICH to REFL45Q element and ~16000 % error for MICH to REFL45I element.

[Motivation]
Before measuring the PRMI sensing matrix, we wanted to estimate how good output matrix diagonalization is.


[Method]
1. Lock PRY and measure open loop transfer function. Compare it with the model to derive optical gain.

2. Measure actuator transfer function of BS and PRM from ISCINF to REFLAIR_RF45_I_ERR in PRY (using the same template used in alog #10450). Calibrate these TFs into m/counts with the optical gain derived in step 1.

3. Closed loop correct TFs measured in step 2. TFs should look like 1/f^2 at 1-300 Hz (see comments on alog #10450). Since output matrix for MICH in PRMI are set to (BS,PRM)=(1,-0.5), these TFs should be equal (see alog #10559 and table below).

-table of actuation efficiency (optic motion to interferometer length change in m/m)-
      PRY      PRCL      MICH
BS    sqrt(2)  1/sqrt(2) sqrt(2)
PRM   1        1         0

4. Calculate expected actuator TFs for MICH to PRCL coupling using the measured TFs. BS ISCINF to PRC length change will be half as that of PRY. BS-0.5*PRM gives the residual MICH to PRCL coupling.


[Result]
1. OLTF_PRCL_1078572000.png: Openloop transfer function of PRY lock. By comparing with the model, this gives PRY optical gain of 1.8 W/m. So, the calibration factor for REFLAIR_RF45_I_ERR in PRY is 4.7e11 counts/m. Note that this calibration factor includes losses in the PD signal chain (e.g. loss from long cable). Also, note that PRM suspension model was 30 % off from the measurement (see #10482; measurement = 0.77 * SUS model). This correction factor is included in the model to derive the optical gain.

2. BSandPRMact_PRY.png: Measured actuator transfer functions for BS and PRM in PRY. x marks show raw measured TFs and dots show closed loop corrected ones. After closed loop correction, actuator TFs look like they follow 1/f^2. From the fit, BS actuator TF is 1.79e12 Hz^2/f^2 m/counts and PRM actuator TF is 1.93e12 Hz^2/f^2 m/counts for PRY. Considering the error bar from coherence and cavity build up fluctuation during the measurement, this 8% difference between BS and PRM is significant (error bars in TF magnitude are derived using the formula in alog #10506). We have done the balancing with the precision of ~10%, so this difference is reasonable.

3. BSandPRMact_MICH2PRCL.png: Estimated MICH to PRCL coupling from actuator diagonalization. Blue dots show BS ISCINF to PRC length change and red dots show BS and PRM combined actuator to PRC length change. Fitted lines show that MICH to PRCL coupling is expected to be supressed by factor of ~4 by actuator balancing. We can improve this supression ratio a little bit by changing the gain balancing between BS and PRM by 8%, but it's not easy to improve more and prove we did more.


[Is this enough?]
This means that our MICH actuator (BS - 0.5*PRM) changes MICH length by 1.79e12 Hz^2/f^2 m/counts and PRC length by 2.06e11 Hz^2/f^2 m/counts. According to Optickle simulation in LIGO-T1300328, sensing matrix for PRMI sideband is

            PRCL    MICH
REFL 45I    3.4e6   2.5e3
REFL 45Q    6.4e4   1.3e5  W/m

So, the estimated effect of residual MICH to PRCL coupling to the sensing matrix measurement is;

MICH to REFL45Q element:   6 % error (= 6.4e4/1.3e5/(1.79e12/2.06e11) )
MICH to REFL45I element: 16000 % error (= 3.4e6/2.5e3/(1.79e12/2.06e11) )

If we ignore MICH to REFL45I element, which is hard to measure anyway, I think this is acceptable.


[Next]
 - Update gain balancing factor between PRM and BS from 1/16 to 1/14.7 (FM5 in H1:SUS-BS_M3_LOCK_L)
 - Update IQ demod phase in H1:LSC-REFLAIR_A_RF45_PHASE_R to minimize PRCL to MICH coupling
 - Measure sensing matrix in PRMI

LASER IS ON

 - Output Power = 28.6 W

 - Watchdog is active

 - System status is good

PMC

 - Locked for 4 days, 7 hours

- Refl Power = 1.2 W, Trans Power = 10.2 W

FSS

- Ref Cav locked for 11 hours

- Alignment is OK, PD threshold = .96 Volts

ISS

- 12% diffracted power

- Saturated 14 hours ago.

PRY is locked (POPAIR_B_RF_18_I is around -0.14) and Yuta's measurement started.  I'll leave it going overnight.

Alexa, Sheila

Tonight we decided to try to charachterize the coupling of alingment fluctuations to the error between the arm resonance and the ALS COMM lock point. We did this using the normalized PDH error signal.  The frequency dependence of this spectrum is unclear- if we were staying on resonance we would just have the cavity pole, but the transfer function of the transmitted light will change as we move over the resonance.  So to make a good calibration we need to lock well enough to stay on resonance.  (This is why we have been trying the AO the last few nights).  For tonight we concentrated on low frequency noise that is dominating our RMS, where the frqeuency dependence won't matter anyway.

We put a 1 Hz excitation onto ETMX pitch, making it large enough to see the second harmonic.  We measured the spectrum of our REFL_DC_BIAS error signal when COMM was locked, and the op lev spectrum with and without the excitations.  The attached screenshot shows the spectrum with and without the excitation.

Measuring the peaks due to the excitation we estimated the coupling coefficient with excitations of 2 different amplitudes, 1.7kHz/urad and 1.5kHz/urad.  We also can esitmate the quadratic coupling from this data, we got 159Hz/(urad)^2 and 170 Hz/(urad)^2

Attached is a plot of linear and quadratic projections based on the Oplev data (up to 4Hz) into the REFL_DC_BIAS path.  It can explain all the noise around the pitch resonance (which is most of the RMS), but not elsewhere.  We had wondered if the coupling was nonlinear and some of our unexplained noise from 1 Hz-50Hz  (or below 0.3Hz) was upconverted angular fluctuations.  Our measurement suggests that this is not the case. 

We were planning to repeat this measurement for ITMX, but so far we have been prevented by and earthquake. 

Since no ISI transfer functions will be running tonight, ETMY overnight transfer functions were started to assess for rubbing on opsws6.

This morning I was able to take some transfer functions on the ETMX :

Top mass to test mass yaw to yaw transfer function : It was saved under /SusSVN/sus/trunkQUAD/H1/ETMX/SAGM0/Data/2014-03-03_H1SUSETMX_M0_PtoPY_WhiteNoise_0p1to10Hz.xml. Coherence is good until 4Hz.

Tested top mass to test mass pitch to pitch transfer function driving through the invP2P filter. The TF looks as a nice single pendulum below 1Hz, but looses coherence afterwards, cf attached plot.

Top mass length to test mass pitch transfer function driving through the L2P decoupling filter. It doesn't seem stable, so this one shouldn't be used for now.

Left to do for ETMX is the UIM pitch/yaw to test mass pitch/yaw transfer function, as well as y2y fitting.

ETMX chamber tripped after Arnaud clicked on a wrong button on the Quad (thanks Arnaud! ).

After resetting the targets on the ISI, we can clearly see that the ISI didn't come back to the same position in ST1-RZ and ST1-RY.

My understanding is that this phenomena had appeared at LLO in the past. The solution chosen is to restore the previous alignment in RZ only. This fix seems good enough for now.

Targets ST1

Targets ST1

After SUS team was gone, we went in the BSC10 to check a potential rubbing issue that has been bothering SEI.

After backing off all EQ stops and making sure that the top mass is free, we've found that the top mass had ROLL tilt, and somewhat smaller PIT. We don't know where this came from, but in my experience TMS angle changes after transporting to the chamber.

We corrected the roll and PIT by moving top balance masses, roughly centered all BOSEMs (the only one that was left untouched is RT) and left it damped.

This morning while working on H1-SR3 the UR magnet/dumbbell was dislodged from the Optics mass. We have gathered up the tools and a replacement magnet/dumbbell assembly. We will attempt to glue a new magnet on tomorrow morning.   

Andres & Jeff

   We attached the new Lower Wire Loop on H1-SR3. Set the pitch and roll of the Intermediate Mass using an optical level. Set the roll of the Optic using the optical level and lowered the Optic onto the new wire loop. The Optic is now suspended on the the new wire loop with almost zero pitch and roll.   

Mitchell and I got the last corner of HEPI Actuaots attached.  IAS was at the ready and noted a need to Yaw CW ~140urads.  The SEI Dial Indicators suggested ~70 shift CCW from last IAS position.  I thought they be better than that but at least they're in the same direction.  I turned the HEPI DSCW Springs to compensate (1/4 Turn on every spring.)  This put us about 20urads to go.  We left it there and checked again after lunch and it looked maybe slightly better, a few urads, and this jived with some slight changes on the DIs.

The last time SEI did an elevation survey combined with the changes on the DIs since then suggest Elevation & Level of the optical table are 0.2mm high of nominal with just 0.2mm of level runout--at spec of 100urads.

With that I zero'd the HEPI Actuator IPS (Inductive Position Sensors) to less that 50 cts, most much less but it is mainly luck at that point.  At the raw IPS there are 655cts/0.001" so comfortably under 0.0001".  I also checked the gaps between the Actuator Plate and the Bellows Shields which form a range of motion limit and sensor protection mechanism, and these seemed mostly centered well enough.  Range of motion and linearity tests will confirm if we are good there.

I'm sure Jason will put in an IAS log, otherwise, SEI/HEPI is good.

Attached are my leveling, DI readings, LoadCell numbers, Springs adjusting notes.  Contact me anytime, if you want to talk about the vudoo

This is a report about a small task that has been in Daniel's commissioning calendar for a long time (see for example alog 10451).

I checked the signals of REFL_A and compared them with the in-air ones to check if they are functional.

The signal levels seem reasonable and therefore I conclude that REFL_A is functional without a problem. See below for more details.

Comparison of the signal level:

Before doing anything, I adjusted the demod phase of REFL_A_RF45 which had not been set to a useful number. It is now set to be 5 deg. This maximized the PRY signal in the in-phase output. On the other hand, REFL_A_RF9 seemed already good and therefore I didn't change the demod phase. Then I locked the PRY and injected a 10 Hz excitation in order to compare the responses between the in-vac and in-air ones using dtt. Note that I only used the in-phase signals as the q-phases don't really give a good signal in this situation. At the same time, the DC power on the PDs were measured to be 14200 cnts and 8020 cnts at REFL and REFLAIR respectively. This means that the in-vac one should show a higher response by a factor of 1.77 due to the difference in the power falling on the diodes.

Unfortunately, I wasn't able to figure our whether S1300533 or S1300534 is in HAM1. So for now I use transimpedance gain of 600 and 730 Ohms for 9 MHz and 45 MHz respectively which should give us a coarse estimation of the signal levels.

Expected and measured ratios of the 9 MHz detectors:

• REFL_RF9_I / REFLAIR_RF9_I = 600 Ohm / 245 Ohm x 1.77 = 4.33
• Measured ratio = 3.8
• Discrepancy is about 14% or 1.14 dB. This is acceptable.

Expected and measured ratios of the 45 MHz detectors:

• REFL_RF45_I / REFLAIR_RF45_I = 730 Ohm / 341 Ohm x 1.77 = 3.79
• Measured ratio = 3.15
• Discrepancy is about 20% or 1.6 dB. This is acceptable.

Thomas Vo, Greg Grabeel
After hearing that LLO had an alignment problem with SM1 and SM2 Thomas and I decided to look and see if we could get a visual confirmation on alignment. Taking the opportunity given by a soft valve close, we stuck a camera up to the viewports and took some pictures. One set of pictures is through the regular glass, and the other are through the Zinc Selenide. The pictures are a little blurry from the long exposure time needed to get anything to stand out, but it looks like we are still good for having the test masses in sight. 

Jeff, Sheila

Last night when Jeff brought the ISIs back after trips due to the first earthquake, he reset the target offsets as we have discussed doing from now on. This moved ETMX ISI RZ (yaw) by 16urad on stage 1, 12 urad on stage 2, RY (pit for TMS) by 3 urad on stage 1, and 2 urad on stage 2. This is at least the third time that we have reset the target values for ETMX, and the second time we have seen a large move. (25 urad seen in RZ in alogs 10596 10602)

If we had changes of less than a urad, either our dither alingment or WFS would be able to correct for that, if we had changes of less than about 5 urad we would still be able to find the baffle PDs easily to recover the alignment.  20 urad though is difficult to recover from. I (Sheila) would prefer waiting for T240s to settle than doing a random walk in alignment over 10s of urad. 

We had a look at the other optics, and they don't seem to move that much. ITMX for example had no changes larger than 100nrad last night.