The attached plot shows frequency and intensity noise measured by the IMC/REFL and second loop ISS sensors.

There is coherence above 1 kHz with intensity  noise. Using the intensity noise coupling TF from alogs 30274 or 29926, one can conclude that it doesn't couple through intensity noise. The intensity noise is at 10^-8 RIN/rtHz at 1 kHz. With a coupling of 10^-13 m/RIN, we are far below the DARM noise.

The frequency noise produced by the PMC length noise is of the order of 1 Hz/rtHz at 1 kHz. It will be suppressed by the FSS, IMC and REFL. As such it is much too small to be responsible for the coupling directly. There is however, coherence with frequency noise as seen by REFL_A_RF9_I in the 1 kHz region. Assuming the REFL control signal is dominated by IMC sensing noise which seems to be around 2 x 10^-4 Hz/rtHz at 1 kHz for 25 W input, see alog 31138, and using the noise coupling from alog 31176, we get a number around 10^-19 m/rtHz at 1 kHz. So, it is conceivable that the PMC noise produces error point offsets in the REFL servo which in turn propagate to DARM as frequency noise.

We saw an increase of the PMC length noise coupling to DARM, when we misaligned SRM by 20 µrad. According T0900142 the requirement for SRM is 2.5 µrad which puts the required 3x10^-6 /rtHz at 1 kHz with a safety factor of 10. So, for 20 µrad, a jitter of 7x10^-6/rtHz at 1kHz is at the DARM noise level at full sensitivity. Our jitter was roughly 5x10^-6/rtHz and it made a difference at the 1x10^-19 level. Maybe somewhat higher than expected but close.

Looking at the IMC WFS signal we can clearly see the PMC length noise injection. If we take the 260 Hz periscope peak as a reference, this doesn't explain the coupling to DARM. What is surprising is that even without length noise injection (REF traces), the coherence between IMC WFS and PMC HVMon is large at frequencies between the jitter peaks.

This measurement was repeated with just the IMC locked at 25 W and ISS second loop enageged. This did not change the HV MON coherence with the IMC WFS nor the coherence with MC_F.

by the way, I noticed this issue because I saw the SDF differences at the end stations were not the same.  Since this is a guardian controlled feature, it might be argued that it would be Not_Monitored.  Were that the case...

In case you are wondering what difference this can make...

The attached asd shows the ETMs 12 and 6 hours ago.  12 hours ago (ref traces) the ETMY was in 250mHz blends while the ETMX was in the 45mHz blend. 6 hours ago was after the ETMY was actually switched to 45mHz blends.

The thick green and brownish curves become much more like the others after the blend switching and moving the blend gain peaking away from the secondary microseismic peak.

The second attachment are trends of theX & Y ARM SUSPOINT Motions based on the ISI's onboard GS13s and the ETMY and ITMY SWSTAT showing when the ITMY blend switched but the ETMY did not and then this morning when the ETMY switched to the same blend as the ITMY.  When the two ISIs are in different blends, the motion is clearly larger although based on these trends.  Based on the XARM Motion though, not clearly a better blend overall.

ETMY_ST1_CONF wasn't switching properly because I had found an issue with the guardian when trying to write some different configurations. I forgot to revert the code to a properly working state. Sorry. I've fixed the configuration, and tested that it works on ETMY.

Lockloss tool cannot connect.

Generally these all look fine with regard to the intention of this test.  There are no outlying base levels in the higher frequency (above the 'details' < 20 Hz) range.

16:51 Daniel and Keita out to LVEA to work on PMC

17:09 Hugh reports that ISI_CONF reporting ETMY at BLEND_45mHz_SC_useism is actually incorrect. It's actually set to the 250mHz.

17:13 LASER tripped (injection locking) while Keita and Daniel working in PSL rack. Jason coming to control room to restart.

17:56 Relocking resumed

17:57 Cheryl on site

For such high microseism situations, it may be worth switching back to the 45 mHz blends for all the test-mass chambers, with or without sensor correction.

We are leaving the IFO in observe, but there is scattering from ISCT1 because we can't move to REFL wfs with the higher ground motion. This is something to look at in the morning, but it caused us many locklosses tonight.  

The IMC WFS offsets that were working early last week don't seem repeatable tonight.

Nutsinee switched the test mass ISIs to BLEND_45_SC_useism, that went OK except for some large glitches when switch ETMX, but when I tried switching to REFL WFS again we dropped the lock.  We probably need to look at finding a better matrix for refl WFS and getting rid of the oscialltion in the centering and IMC WFS. 

Speculation about REFL WFS.  Yesterday I was concerned that PR2 had moved what seemed like a lot (8-10urad) when I did the Inital Alignment.  I would expect something smaller like 2urad.  I couldn't find a cause for that, but I did notice IM4 also changed by 20urad in yaw.  A change of 20urad in yaw of IM4, assuming PRM moved to match the change of the PRC input beam, would propigate to the REFL WFS, and my estimate for the change in beam position at REFL WFS to be 168um.  I don't know the beam size on REFL WFS, but the IMC WFS is about 250um, so if REFL WFS is about the same, the 168um is a beam position change of ~70%.

Summary

A refined analysis of the L1, L2 and L3 stange actuation strenghts was done using the data from last several days that include several low-noise lock stretches. Actuation strength factors are:

K_U = 8.020^-8 +/- 2.983^-10 N/ct   ( std(K_U) / |K_U| = 0.0037 )

K_P = 6.482^-10 +/- 2.748^-12 N/ct   ( std(K_P) / |K_P| = 0.0033 )

K_T = 4.260^-12 +/- 1.313^-14 N/ct   ( std(K_T) / |K_T| = 0.0031 )

Details

Following 4 lines were used to calculate the factors: UIM (L1) line at 33.7 Hz, PUM (L2) line at 34.7 Hz, TST (L3) line at 35.9 Hz and PcalY line at 36.7 Hz. The most recent DARM model parameters were used for this analysis. Also, values past Nov 5 were calculated with the updated DARM filters (see LHO alog 31201), not accounting for this would produce results biased by 1-2%.

Each data point is a quantity calculated from 10s FFTs. The outliers were removed in two steps:
- took the mean and the standard deviation of all data points in intervals when the IFO range was >=50 MPC, removed 3-sigma outliers;
- removed the 3-sigma outliers from the mean of the remaining data points.

The mean values and the standard devitaions noted above were taken from GPS time interval [1162369920 1162413500], ~11 hours of low-noise data (blue markers). Standard errors on the mean values, std(K_i) / sqrt(N), are orders of magnitude smaller compared to the Pcal and the DARM loop model uncertainties (number of data points in the seletected interval - N=4251).

For preliminary results from Nov 4 data and before see related reports: 31183, 31275.

Recall the ER8/O1 values for these coefficients were

    'Optic'      'Weighted Mean'    '1-sigma Uncertainty'    '1-sigma Uncertainty'
    'Stage'      '[N/ct]'           '[N/ct]'                 '%'                  
    'ETMY L1'    '8.17e-08'         '3.2e-09'                '3.9'                
    'ETMY L2'    '6.82e-10'         '5.2e-13'                '0.076'              
    'ETMY L3'    '4.24e-12'         '4.1e-15'                '0.096' 
from LHO aLOG 21280.

Comparing against numbers above,
    KU = 8.020-8 +/- 2.983-10 N/ct   ( std(KU) / |KU| = 0.0037 )
    KP = 6.482-10 +/- 2.748-12 N/ct   ( std(KP) / |KP| = 0.0033 )
    KT = 4.260-12 +/- 1.313-14 N/ct   ( std(KT) / |KT| = 0.0031 )

This means a change of
               (ER8 - ER10)/ER8 = 
    ETMY L1        0.0183
    ETMY L2        0.0495
    ETMY L3       -0.0047

We will compare these numbers against those determined by frequency-dependent transfer functions, e.g. the to-be processed data from LHO aLOG 31303, and update the low-latency/ calibration accordingly next week. It will also be interesting to re-cast the L1 and L2 numbers into a combined actuation strength change from ER10/O1, and compare it against the constantly calculated kappa_PU and check consistency there.

Data points prior to DARM filter update mentioned in the report were analyzed with the help of following DARM model parameters:

ifoIndepFilename : ${CalSVN}/Runs/PreER10/Common/params/IFOindepParams.conf (r3519)
ifoDepFilename   : ${CalSVN}/Runs/PreER10/H1/params/H1params.conf (r3640)
ifoMeasParams    : ${CalSVN}/Runs/PreER10/H1/params/H1params_2016-10-13.conf (r3519)

and after the the DARM filters were updated (GPS 1162336667) the following configuration was used:

ifoIndepFilename : ${CalSVN}/Runs/PreER10/Common/params/IFOindepParams.conf (r3519)
ifoDepFilename   : ${CalSVN}/Runs/PreER10/H1/params/H1params_since_1162336667.conf (r3640)
ifoMeasParams    : ${CalSVN}/Runs/PreER10/H1/params/H1params_2016-10-13.conf (r3519)

Scripts were uploaded to CalSVN at

${CalSVN}/Runs/PreER10/H1/Scripts/Actuation/2016-11-08/

5 days SLM data (75 MB): ${CalSVN}/Runs/PreER10/H1/Measurements/Actuation/2016-11-08/

Plots: ${CalSVN}/Runs/PreER10/H1/Results/Actuation/2016-11-08_H1_UPT_act_strengths_*

We discovered that in the single-line analysis we had an incorrect sign for TST stage actuation (we incorrectly set the sign of the N/ct coefficient).

The updated results have been posted in LHO alog 31668.

A better plot showing the relationship between the ILS and PMC mixer and HVMon signals.

Reducing the ILS gain by 16 dB increases the noise seen by the PMC by the same amount below 1 kHz. This change reduced the ILS ugf from ~10 kHz down to ~1 kHz.

PMC and HPO PZT characterization/calibration

The PMC PZT is decribed in alog 30729:

• Model: PI PAHH-0013
• Capacitance: 63 nF
• Travel: 4 µm/kV
• Series resistor: 3.3 kΩ
• Pole: ~770 Hz.

The ILS PZT is

• Capacitance: 120 nF
• Travel: 15 µm/kV
• Series resistor: 3.3 kΩ
• Pole: ~400 Hz.

Here is a frequency coupling TF calibrated into meters per hertz, using the above data.

The calibration uses the whitening gain (12 dB), the digital gain (0.36 ct/ct), the ADC gain (2¹⁶ ct / 40 V), the demod gain and transimpedance (2600 V/W), and an assumed CARM plant with a dc gain of 13 mW/Hz and a pole at 0.63 Hz. The numbers for the plant come from OLTF budgeting from O1 (so these numbers are quite old and may have changed).