J. Kissel

I've grabbed spectra from all possible degrees of freedom of the ground, HEPI pier, and ISI ST1 for the four operational ground sensors and the four operational BSC-ISIs during a very windy and noisy afternoon this past Thursday, Mar 6 2014 at 22:15 UTC. This will hopefully assist modelling efforts to design blend filters that might be able to withstand such input noise. Unfortunately, because Sebastien was commissioning a few chambers, and we had to reboot ETMX to get his GND T240 stored in the right place, there wasn't any long stretch of time during that day in which all platforms were at comparable performance (hence the differences in the ISI ST1 performance). Also, I'm not sure I believe what the rotational HEPI L4Cs are saying at the microseism.

The spectra are attached, but they were created by the following DTT templates,
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/Common/Data/
2014-03-06_2215UTC_GroundMotion_ASDs.xml
2014-03-06_2215UTC_HEPIPierMotion_ASDs.xml
2014-03-06_2215UTC_ISIST1Motion_ASDs.xml
and they were also exported to the following files
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/Common/Data/
2014-03-06_2215UTC_Windy_GroundMotion_ASDs_ITMY-XYZ_HAM2-XYZ_HAM5-XYZ_ETMX-XYZ.txt
2014-03-06_2215UTC_Windy_ISIST1Motion_ASDs_BS-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_ISIST1Motion_ASDs_ETMX-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_ISIST1Motion_ASDs_ITMX-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_ISIST1Motion_ASDs_ITMY-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_PierMotion_ASDs_BS-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_PierMotion_ASDs_ETMX-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_PierMotion_ASDs_ITMX-XYZRXRYRZ.txt
2014-03-06_2215UTC_Windy_PierMotion_ASDs_ITMY-XYZRXRYRZ.txt
where the last part of the file name indicates the order in which the channels have been exported.

Alexa, Sheila

We tried engaging the refl DC bias path with the 1.6Hz pole :40Hz zero engaged.  We were able to measure a tranfer function using 0dB on the CM in1 gain, and -80 in REfl DC bias, which has coherence to about 2Hz. (the UGF is around 3.5Hz).  We tried to push the gain up and engage the boost to get a better measurement, but now we seem to have an earthquake from Mexico tripping our ISIs, so we are done for the day.

All ISIs except for the BS tripped Mar 10th 2014 ~00:58 UTC, most likely from 6.3 Mag Mexican Earthquake (see USGS Page), which happened at Mar 10th 00:38:20 UTC. *sigh* Well, THAT's annoying. Delightfully however, once untripped, the guardian brought the HAM2 and HAM3 ISIs back up to full isolation. 

Yuta, Sheila, Alexa

Today we found an alignment that should be acceptable to both PRMI and the Xarm, in the hopes that the green team and red team will not each have to change PR2 significantly each day. 

First Yuta aligned PRX, then we aligned the Xarm, locked the IR to the X arm, and moved PR2 and IM4 to point the beam down the xarm.  After this the alignment of PRX was way off and unlockable.  We checked that the beam was centered on POPAir B, then restored PR2 to the intial PRX alignment.  Then Yuta aligned PRM by hand, and walked PR2 back to the arm alignment. Finally Yuta realinged PRY.  A screenshot of the final positions is attached.

Yuta has changed the dither guardian script for PRX so that the PR2 dither is now fed back to PRM instead of PR2. 

Hopefully this means that the PRMI and arm alignments will stay compatable and both the red team and green team don't have to spend as much time aligning each day. 

J. Kissel

While gathering data of the ground motion from Thursday's windy afternoon, I found that the calibration filter used to turn the ground inertial sensor into (asymptoting to) 1 [nm/s] (at high-frequency) for the new, temporary, T240 at End X (see LHO aLOGs 10594, 9758, and D1400077) was incorrect. The "Cal" filters in FM1 of the H1:ISI-ETMX_ST1_GNDSTSINF_[A,B,C]_[X,Y,Z] banks were ON and still calibrating for an STS2 read-out chain, i.e.
1 / (1500 [V / (m/s)] * 40 [V/V] * 2^16/40 [ct/V] * 1e-9 [(m/s) / (nm/s)]) = 10.1725 [(m/s) / ct]
These filters were most likely installed and turned on by some script that was preparing for the permanent solution; not surprising.

I've installed a new filter in FM2 of all nine banks, called "T240Cal" with the following gain:
1 / (1200 [V / (m/s)] * 2 [V/V] * 2^16/40 [ct/V] * 1e-9 [(m/s) / (nm/s)]) = 254.3132 [(m/s) / ct]
where I've assumed that the Trillium Interface Chassis is configured in its low-gain mode, with a gain of 2.0. 

I attach a spectra of data in the past, comparing all four ground inertial sensors, with the ETMX GND sensor corrected for the factor of 
(254.3132 [T240] / 10.1725 [STS]) = 25.0 [T240/STS]
difference in gain between the STS and T240 calibration. Where we expect the ground motion to be coherent, namely between 0.1 and 0.5 [Hz], the ETMX sensor matches all three corner station's sensors exquisitely, and the micro seismic peak is roughly 1e-6 (m/s)/rtHz as expected.

As of now, until the T240 is replaced with an STS2 as designed, the ETMX_ST1_GNDSTSINF_[A,B,C]_[X,Y,Z] filter banks should have FM2 ON and FM1 OFF. Once the T240 is replaced by an STS2, we can switch back to using FM1, and "T240Cal" should be removed from FM2 to avoid confusion.

All calibration values were obtained from D1001575.

Just finished up the March Public Tour.  I took the group up on the roof around 2:50-3:00pm.

Engaged DOF1P, DOF1Y and DOF2Y, dithered ITM and ETM, and measured the sensing matrix based on OL (assuming that OL calibration is now correct).

The sign follows the SUS convention that positive PIT = mirror points down, positive YAW = counter clockwise viewed from the top.

As was observed before, WFSA is a good YAW hard mode sensor, WFSB is a good PIT hard mode sensor.

Since neither of the WFSs is good soft mode sensor, I made these:

DOF2P = -4.19 WFSAP + WFSBP

DOF2Y = WFSAY + 1.1 WFSBY

After making these, all four DOF loops were closed and it worked, with one caveat: It seems like DOF2P wants a large offset in order for the green transmission to be maximized. I tried +2500 cts offset and it was good (transmission touches 850 cts). Without this, the transmission stays between 650 and 750.

Unfortunately I cannot give DOF2P an offset before the master switch, and I put this offset in the feedback filter itself. When IFO unlocks the integrator will keep integrating, destroying the IFO alignment.

So I disabled DOF2P input AND offset, and left other three DOFs, for tonight.

It's still slow.

Daniel, Alexa, Keita, Arnaud, Sheila

Tonight we measured the same noise spectrum of the normalized arm PDH spectrum that we measured tuesday night, with the WFS on at low gain.  The noise was not improved, it even seemed worse. 

We then tried feeding the normalized PDH back to the CM board though input 2.  With a gain of 18 in -500 in REFL_DC_BIAS and 0 in the CM board Input 2 and positive polarity.

We saw that the error signal was supressed.  The transfer function we measured for this loop didn't make sense, we measured a ugf of 500Hz and 180 degrees phase.  We weren't able to calibrate the nosie spectrum we then measured, not trusting the measurement of the loop gain. 

The transmitted power fluctations were reduced by adding the feedback from the IR, but still fluctuated from 1 to 0.5, at around half a hertz. 

The IR was locked to the cavity starting at around 6:30 UTC, most of the time until the ITMX ISI tripped at around 7:30  UTC.  I reset the target offsets before bringing it back up, after which Alexa realinged the cavity by moving ITMX 2.5urad in pitch.  Trying to bring it up I tripped it twice more trying to reengage the Tcrappys (even though everything was green, it seems we need to wait until the number are around a few hundred.) Arnaud brought it back by switching to Tcrappy one DOF at a time on stage 2, and sensor correction is now left off. 

I took another amplitude spectrum of the noise out of the PFD IMON in the COMM PLL to VCO loop. The PLL was locked; however we had not handed off. The two compensation filters were on and the input gain was 27dB. I have attached the data. The flatness which we were puzzled by last time has disappeared...

I did also see the traveling noise that seems to come from electronics cross-talk. This moving peak was about 3kHz wide (approzimately 12 degrees).

J. Kissel

Following the same procedure outlined in LHO aLOGs 9453 and 9079, I balanced the coils on SUS ITMY UIM/L1, ITMX PUM/L2, and ITMX UIM/L1. The final balanced gains are

             ITMX UIM     ITMY UIM    ITMY PUM
UL            -0.965      -0.997       +1.028
LL            +1.025      +0.976       -0.911
UR            +0.970      +1.019       -1.091
LR            -1.030      -0.998       +0.968

The precision on the ITMX UIM and ITMY PUM numbers is within the usual +/- 0.5%, but for some reason I was able to get a crazy amount of SNR on ITMY UIM, so the numbers are good to with 0.05%. 

This balancing has reduced the L3 P and Y caused by pringle excitation at 4 [Hz] by
Optic    Stage      DOF       Reduction Factor @ 4.0 [Hz]
ITMX      UIM        P               > 24.2 (peak below noise, totally incoherent)            
                     Y               > 1.39 (already balanced well, totally incoherent after balance)

ITMY      PUM        P               25.6 (peak still 95% coherent*)
                     Y               37.4 (peak still 80% coherent*)

ITMY      UIM        P               > 124.2 (peak still 68% coherent, but buried)
                     Y               19. 0 (peak still 90% coherent)

* For ITMY PUM, I could not reduce the Q phases to as small as I normally get, implying there is some other noise contributing to the imbalance unrelated to the knob I'm tuning. Unclear what that could be, but I guess this is why I couldn't reduce the imbalance low enough that the excitation became buried in the noise as I could with the other stages.

I attach the figures of merit for reducing the imbalance. All SUS have had these values captured in there safe.snaps, which have been committed to the repository... except for ITMY PUM which I found not stored while writing this entry. Will store them ASAP.

Running from OPSWS0. Already had a peek with DTT, and no change after todays fiddling with TMS cables. But, maybe more data will tell us...more. TMS is plugged in and damping now, as well as the quad.

PT124B increased(ing) as a result -> The removal of atmospheric pressure from the O-ring valve's O-ring may have released some dissolved gas -> Flex line connecting RGA to 1.5" O-ring valve doesn't look to be applying any torque to 1.5" valve -> I will be monitoring PT124B from home

Got the final Actuators attached to HAM4 today.  I still need to install the position sensor that was experiencing an interference.  And then access the total position before final closeup.

Tweeked the DSCW Springs to pull the system back up from the additional ACB weight.  We adjusted things attempting to bring the Dial Indicators back to the post final alignment numbers Jim recorded on 5 March.  There is a 10mil (1/4mm) west shift but we are still well within the +-3mm tolerance.  Otherwise we have less than 0.1mm vertical shift and much less than that N/S.

So, ready for HEPI Actuators.

(Jax, Daniel)

Today we measured the RF levels in the ISC field and remote racks at EY and set nominal RF values in the MEDM interface. 

Installed attenuators by cable number:

2dB: 

18-1B2 (RF to phase modulator), 18-1, 13B (RF Preamp to Phase/Freq Discriminator), 14-2B (RF to VCO), 19-1 (71 MHz RF Dist. Amp to Oscillator), 14-1 (24.4 MHz RF Dist. Amp to Oscillator)

3dB: 

16-1 (Freq Divider to Phase/Freq Discriminator)

8dB:

17-1 (VCO to Freq Divider)

15 dB*:

18-5B (RF to VCO)

*Here we would have preferred 12 dB to be consistent with EX as per alog 9466, but didn't have one on hand in the big box o' attenuators.

---

During this process, we discovered the delay line had no output. After cracking it open, we found that one of the ICs (U22) had fried in spectacular fashion - likely a victim of an upside-down power cable at some point. I grabbed a spare (S1103442) from MY, gave it a quick once-over to make sure it works, then installed it at EY.

8:30 am, HFD department, fire hydrant flushing/testing.
9:00 am, Mitchell, Travis and Andres to Y-End, ACB install.
9:00 am, Aaron connect cables for new chassis, CM summing chassis by PSL area.
9:30 am, HFD department, second unit to check on RAFAR boxes ====> done by 11:15 am
10:08 am, Cyrus and Jim to Mid-Y, rack and stack work per WP#4466.===> break for lunch at 12:15 pm.
10:00 am, Thomas and Greg to LVEA North bay area, prep HEPA filter fan unit for craning.
10:55 am, Hugh to LVEA HAM4 area, HEPI installation.
11:21 am, Alexa, X-End, field rack measurements ====> done by 11:53 am.
11:30 am, Thomas and Greg to North bay area, crane HEPA filter on to a table.
11:37 am, Kyle to X-End, check up on access.  To Y-End, check up on purge air====> done by 12:10 pm.
11:40 am, Apollo crew moving ISI to high bay area ====> done by 11:59 am.
1:00 pm, Karen to Y-end, cleaning.
1:09 pm, Keita to Y-End, TMS cabling status.
1:24 pm, Andres to LVEA South and West bay area, hunting for SUS components ====> done by 2:28 pm.
1:30 pm, Alexa and Sheila to X-End, LVEA area.
1:48 pm, Jim and Cyrus, back to Y-Mid to continue with rack and stack ====> done by 3:14 pm.
1:50 pm, Hugh to LVEA HAM4 area, continue with work, then I saw him at Y-End, so who knows.
4:00 pm, Kyle done "making noise" West bay area of LVEA, on elevated BT slab near GV6.
 

THESE CALIBRATION FACTORS HAVE CHANGED

Per Keita's ALOG 10331 and 10454, I have adjusted the optical lever calibration gains for ETMX and ITMX to reflect a more accurate method of calibration that was performed by Keita with the baffle diodes.

ETM

ITM

J. Kissel [with lots of help from K. Kawabe, K. Arai, S. Ballmer, and K. Izumi]

I've balanced the coils on the M2 and M3 stages of the H1 SUS PR2 using Keita's Technique (see LHO aLOG 9079 -- which, now that I understand -- I'll make sure to supplement this aLOG with kLOG comments about it). However, before I exercise my didactic tactics, the answer is:

H1 SUS PR2
Channel     Balanced COILOUTF Gain
M2 UL            -0.994 
M2 LL            +1.039 
M2 LR            +0.962
M2 UR            -1.005

M3 UL            -0.962
M3 LL            +1.043
M3 UR            +0.954
M3 LR            -1.034

I attach the results of the balancing as measured by the M3 OSEM sensors behind the optic, one for each stage of drive balancing. The left two panels of each attachment (Amplitude Spectral Density and Coherence) show the performance AFTER the balancing, and the right two panels show the performance BEFORE the balancing, where coefficients were just set to +/- 1.0. This balancing has reduced the coupling (at 4.1 [Hz]) as follows (using the M3 OSEMs as the figure of merit, which -- details in notes below -- are imperfect):

   DOF                  Reduction Factor @ 4.1 [Hz]
M2 Pringle to M3 P           > 178               (peak is in the noise, and only ~60% coherent)
M2 Pringle to M3 Y             35

M3 Pringle to M3 P             1.4
M3 Pringle to M3 Y             4.5

The next step is to take a full suite of M2 and M3 L/P/Y to P/Y, "off-diagonal" transfer functions with the newly balanced coils, as has been done with *unbalanced* coils on H1SUSBS and H1SUSPRM.

I have captured a new safe.snap that includes these new gains and committed it to the userapps repo.

Expert Notes for next time:
- Three different suspensions, three different people, and three different options for sensors resulted in three different details of how the the process was done, but the process is the same, in principle. With PR2, the only option for sensor demodulation were the sensor side of the OSEMs at the bottom stage. Because these sensors are not perfectly balanced, the precision to which I could improve the balancing was limited -- much more so on the M3 stage than the M2 Stage. I'll explain the details below.

- These coefficients were established to higher precision, but were rounded off to the nearest 1000th's digit because they will be easier to track, entirely visible on the MEDM screen, and the higher precision had little-to-no affect on the goodness of balancing. 

- The templates for measuring the performance can be found here:
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PR2/Common/Data/
2014-01-22_H1SUSPR2_M2_CoilBalancing.xml
2014-01-22_H1SUSPR2_M3_CoilBalancing.xml

- The script used to perturb the coil balancing based on the results of the LOCKIN tool (authored by Kiwamu, made slightly more generic by me),
/ligo/svncommon/SusSVN/sus/trunk/Common/PythonTools/perturbcoilbalance_fourosem.py
Note, the script isn't fancy enough to perturb the gains automatically to minimize the demodulated error signal, that's done by-eye using a few by-hand iterations of this script and watching the results in StripTool.

- I've used a compromise of filters than Kiwamu and Keita inside the LOCKIN, which I'll motivate in the comments below. For the oscillator clock frequency band pass (in the DEMOD_SIG banks) I used
butter("BandPass",2,3.5,4.5)
and called it "BP4.1Hz," and for the I and Q low-pass filter, I used
cheby1("LowPass",2,3,0.05)
and called it "CLP50mHz."
These seem to have worked out well (for my patience level), and can be copied as long as the clock frequency remains the same (which should be assessed anew for every SUS type.)