ID 
Date 
Author 
Type 
Category 
Subject 
17510

Tue Mar 14 15:46:06 2023 
Tomohiro  Update  IMC  Diagonalizing YAW output matrix using a different method  Alex, Anchal, and I adjusted the number of the MC2TRANS column in the YAW output matrix. We used the same method in 40m/17504 but the amplitude of oscillator for Lock In Amplifier is increased from 1 to 4.
The corrected numbers of the column in the output matrix is as follows:

MC2_TRANS 
MC1 
5.5196 
MC2 
2.8778 
MC3 
5.2232 
We did the step response test for the corrected output matrix. The sum of offdiagonal terms was 0.62, which is the minimum value. Attachment 1 is the step response test result. From the figure, the reduction of the sum is because the column MC2_TRANS can diagonalize better. We can find out the property from Attachment 2. 
Attachment 1: step_response_YAW_140323.pdf


Attachment 2: Mar14_Dfactor.pdf


17511

Tue Mar 14 18:44:39 2023 
yuta  Update  BHD  LO phase noise measurements in ITMX single bounce, MICH and FPMI  [Anchal, Yuta]
We have measured LO phase noise in ITMX single bounce, simple MICH and FPMI configurations with LO phase locked with BH55 or BH44.
We found that BH55 and BH44 have almost exactly same noise in ITMX single bounce, but BH44 is noisier than BH55 in MICH and FPMI configurations.
In any case, LO phase can be locked within 0.1 rad RMS, so optical gain fluctuations in BHD_DIFF should be fine for BHD locking.
Method:
 We have locked ITMX single bounce vs LO, AS beam under MICH locked with AS55_Q vs LO, and AS beam under FPMI locked with REFL55 & AS55 vs LO, using BH55_Q or BH44_Q
 In each IFO configuration, we have minimized I phase to set RF demodulation phases for BH55 and BH44.
 In each IFO configuration, optical gain of BH55_Q and BH44_Q was measured by elliptic fit of XY plot for BH55_Q vs BHDC_A or BH44_Q vs BH55_Q.
 For each LO_PHASE lock, feedback gain was adjusted to set the UGF to around 50 Hz, and actuator used was LO1.
 LO_PHASE_IN1 was calibrated using the measured optical gain, and LO_PHASE_OUT was calibrated using LO1 actuator gain of 26.34e9 /f^2 m/counts measured in 40m/17285.
 To convert meters in radians, 2*pi/lambda is used (which means dark fringe to dark fringe is pi).
 Below summarizes the result of RF demodulation phases and optical gains (whitening gains were 45 dB for BH55 and 39 dB for BH44). RF demod phases aligns well with previous measurement, but optical gain for BH44 seems higher by an order of magnitude compared with 40m/17478 (whitening gain changed??). Optical gain for BH55_Q is consistent with previous measurement in 40m/17506 (note the demodulation phase change).
LO_PHASE lock in ITMX single bounce
Demod phase Optical gain filter gain
BH55_Q 99.8 deg 7.6e9 counts/m 0.3
BH44_Q 6.5 deg 1.3e10 counts/m 0.15
LO_PHASE lock in MICH
Demod phase Optical gain filter gain
BH55_Q 67.7 deg 6.1e8 counts/m 3.9
BH44_Q 31.9 deg 8.5e8 counts/m 3.1
LO_PHASE lock in FPMI
Demod phase Optical gain filter gain
BH55_Q 35.7 deg 3.4e9 counts/m 0.65
BH44_Q 9.3 deg 4.3e10 counts/m 0.84
Result:
 Attached are calibrated LO phase noise spectrum in different IFO configurations.
 In ITMX single bounce, LO phase noise estimated using BH55 and BH44 are almost equivalent, and LO phase noise inloop is ~0.04 rad RMS.
 In MICH, LO phase noise estimated using BH44 is noisier than BH44 at around 2060 Hz for some reason. LO phase noise inloop is ~0.04 rad RMS for both cases.
 In FPMI, LO phase noise estimated using BH44 is noisier than BH44 above ~20 Hz for some reason. LO phase noise inloop is ~0.03 rad RMS for both cases. Dark noise is not limiting the measurement at least below 1 kHz.
Jupyter notebook: /opt/rtcds/caltech/c1/Git/40m/measurements/BHD/BH55_BH44_Comparison.ipynb
Next:
 Lock MICH BHD with BH55 and BH44, and compare LO phase noise contributions to MICH sensitivity
 Investigate why BH44 is noisier than BH55 in MICH and FPMI (offsets? contrast defect? modematching?)
 Reduce 60 Hz + harmonics in BH55 and BH44 
Attachment 1: BH555_BH44_LO_PHase_Control_Comparison.pdf


17512

Thu Mar 16 13:31:25 2023 
Tomohiro  Update  IMC  Diagonalizing YAW output matrix using a different method  Purpose
 To adjust the components of the WFS2 column in the YAW output matrix.
 To check the value of the offdiagonal components of the WFS1 column.
Method
Alex, Anchal, and I used the same method in 40m/17504 to adjust the components of the WFS2 column. And we did the same step response test to check the value of the offdiagonal components in the YAW output matrix.
Used script & file
All the scripts & files are stored in /opt/rtcds/caltech/c1/Git/40m/scripts/MC/WFS/ directory.
 DiagnoalizatingMethod.ipynb: for adjusting the components and replacing the new output matrix,
 toggleWFSoffsets.py: for doing the step response test,
 IOO_WFS_YAW_STEP_RESPONSE_TEST.py: for analyzing the step response result.
Result
We changed the WFS2 column as follows

From 
To 
MC1 
1.3029 
1.8548 
MC2 
0.15206 
0.1357 
MC3 
0.92391 
0.40158 
We can successfully diagonalize the WFS2 column. The sum of the offdiagonal components is slightly reduced. However, WFS1 has worse diagonalization.
The same step response test should be performed on a different day to see if the results change. It is because the multiple causes could exist: the influence of the changed other columns, the long time drift, the day to day change, and so on. 
Attachment 1: step_response_YAW_160323.pdf


Attachment 2: Mar16_Dfactor.pdf


17513

Fri Mar 17 17:27:58 2023 
Alex, Tomohiro  Update  IMC  Arm Cavity Noise injection with WFS1/2 PIT and YAW  Tomohiro and I performed some tests under Rana's guidance to find cross corelations between WFS1 and WFS2 output signals in both pitch and yaw. We performed this test to further understand the degree to which our output matrices have been diagonolized.
Seen in attachment 1 is our base level with no injected noise source. In each figure, we also have inlcuded the coherence plot which compares each control signal to the overalll YARM power signal.
Attachments 25 display our results for injecting noise into each control signal individually.
We found the following corelations for each respective test:
Control Signal with Noise 
Corelated signals (order) 
WFS1 PIT 
WFS1 YAW, WFS2PIT, WFS2 YAW (all equally corelated) 
WFS1 YAW 
WFS1 PIT, WFS2 YAW, WFS2 PIT (most to least) 
WFS2 PIT 
WFS1 PIT, WFS2 YAW, WFS1 YAW (most to least) 
WFS2 YAW 
WFS2 PIT, WFS1 YAW (all equally corelated) 
We judged our corelated signals by the peaks seen from out noise injection on the power spectrum as well as by their coherence at the same frequencies of our noise (20Hz30Hz) compared to the overall power spectrum of YARM.
Performing this measurement was done using diaggui and awggui. The diaggui files for each test are saved at: "users/Templates/singleArmCal/ArmCavityNoise_230317_2_WFS1_PIT"
To properly fix each of the control signals to the same magnitude plotted for YARM output, we callibrated each plot using the settings seen in Attachment 7. First the units were changed on the plots to represent the true scale of each measurement:
We found that the ETMY actuation strength is 10.843e9 / f^2 (from 17376) and used this to clibrate the plots to the nanometer scale. Next the gain was adjusted such that each plot would align over the YARM output when noise was injected onto it, setting a basis for all four measurements.
Finally, some filtering poles were added to the callibration for each plot such that it resembled that of the filters seen by the YARM ouput signal. (RXA: this is the 28 Hz ELP filter to simulate the dewhitening filters)
The measurements were taken with the settings seen in Attachment 8, and noise injected using the parameters seen in attachment 9.
RXA: Some edits/comments:
The noise was injected as bandlimited random noise with a Normal distribution. We used noise rather than lines so as to capture the linear and bilinear noise contributions. In the case where the coupling is mostly bilinear, we would not expect to see much coherence.
The first attachment is a ASC noise budget for the single arm  in the high gain mode, the noise does not limit the noise as seen by the arm. Next is to see if its due to the MC dewhitening filters being on/off? 
Attachment 1: ArmCavityNoise_230317_2.pdf


Attachment 2: ArmCavityNoise_230317_2_WFS1_PIT.pdf


Attachment 3: ArmCavityNoise_230317_2_WFS2_PIT.pdf


Attachment 4: ArmCavityNoise_230317_2_WFS1_YAW.pdf


Attachment 5: ArmCavityNoise_230317_2_WFS2_YAW.pdf


Attachment 6: Screenshot_20230317_172334.png


Attachment 7: Screenshot_20230317_172447.png


Attachment 8: Screenshot_20230317_172400.png


17514

Mon Mar 20 20:27:30 2023 
yuta  Update  BHD  LO phase noise contribution in MICH BHD  [Paco, Yuta]
MICH was locked with balanced homodyne readout with LO phase locked using BH55_Q and BH44_Q.
It turned out that BH44_Q gives better LO phase in MICH configuration (in FPMI, BH55_Q is better; see 40m/17506).
LO phase noise seems to contribute to MICH sensitivity in 30200 Hz region in BH55 case, and 30100 Hz in BH44 case (this was not the case in FPMI BHD, see 40m/17392).
The mechanism for this coupling needs investigation.
MICH BHD sensing matrix:
 MICH BHD sensing matrix was measured when MICH is locked with AS55_Q and LO_PHASE is locked with BH55_Q or BH44_Q.
 MICH UGF was at around 50 Hz, and LO_PHASE UGF was at around 10 Hz.
 BHDC_DIFF had better sensitivity to MICH when LO_PHASE was locked with BH44_Q.
 BH44 component was not measured well.
MICH sensing matrix with MICH locked with AS55_Q and LO_PHASE locked with BH55_Q
Sensing matrix with the following demodulation phases (counts/m)
{'AS55': 2.1, 'REFL55': 76.01784975834194, 'BH55': 63.16236453101908, 'BH44': 39.01036239539396}
Sensors MICH @311.1 Hz LO1 @315.17 Hz
AS55_I (+0.40+/6.23)e+07 [0] (0.83+/3.01)e+07 [0]
AS55_Q (+1.38+/0.26)e+09 [0] (+0.76+/6.58)e+07 [0]
BH55_I (3.22+/0.37)e+09 [0] (0.81+/8.42)e+07 [0]
BH55_Q (+4.03+/0.52)e+09 [0] (4.01+/1.05)e+08 [0]
BH44_I (0.06+/4.22)e+10 [0] (+0.29+/4.63)e+10 [0]
BH44_Q (0.03+/3.21)e+11 [0] (+0.21+/3.12)e+11 [0]
BHDC_DIFF (1.07+/0.39)e+09 [0] (3.35+/7.47)e+07 [0]
BHDC_SUM (+2.07+/0.57)e+08 [0] (+0.32+/1.65)e+07 [0]
MICH sensing matrix with MICH locked with AS55_Q and LO_PHASE locked with BH44_Q
Sensing matrix with the following demodulation phases (counts/m)
{'AS55': 2.1, 'REFL55': 76.01784975834194, 'BH55': 63.16236453101908, 'BH44': 39.01036239539396}
Sensors MICH @311.1 Hz LO1 @315.17 Hz
AS55_I (+0.22+/5.36)e+07 [0] (+0.91+/3.10)e+07 [0]
AS55_Q (+1.43+/0.08)e+09 [0] (0.78+/7.45)e+07 [0]
BH55_I (+4.92+/5.18)e+08 [0] (5.20+/7.93)e+07 [0]
BH55_Q (1.45+/0.75)e+09 [0] (+1.76+/0.59)e+08 [0]
BH44_I (+0.01+/1.14)e+11 [0] (+0.02+/1.08)e+11 [0]
BH44_Q (+0.03+/1.95)e+11 [0] (+0.07+/1.98)e+11 [0]
BHDC_DIFF (+3.05+/0.17)e+09 [0] (+1.70+/2.51)e+07 [0]
BHDC_SUM (2.33+/0.23)e+08 [0] (+0.19+/1.53)e+07 [0]
 Jupyter notebook: /opt/rtcds/caltech/c1/Git/40m/scripts/CAL/SensingMatrix/ReadSensMat.ipynb
MICH BHD locking:
 MICH lock with AS55_Q was handed over to BHD_DIFF using following ratio:
C1:LSCPD_DOF_MTRX_3_4 = 1 (AS55_Q to MICH_A)
C1:LSCPD_DOF_MTRX_4_34 = 1.34 (BHDC_DIFF to MICH_B, when BH55_Q is used)
C1:LSCPD_DOF_MTRX_4_34 = 0.47 (BHDC_DIFF to MICH_B, when BH44_Q is used)
MICH BHD noise budget:
 FM2 of C1:CALMICH_CINV was updated to 1/1.4e9 = 7.14e10 to use measured optical gain.
 Dark noise was measured at C1:CALMICH_W_OUT with PSL shutter closed, PD DOF matrix at various settings for various readout scheme.
 Attachment #1 shows MICH sensitivity with MICH locked using AS55_Q (green), BHD_DIFF under BH55_Q (blue), BHD_DIFF under BH44_Q (red). BH44 case gives the least noise due to larger optical gain. However, there are excess noise at around 100 Hz, when MICH is locked with BHD_DIFF. The excess noise (bump at around 50 Hz) was similar to what we saw in LO phase noise estimate (40m/17511).
 At low frequencies below ~30 Hz, the MICH sensitivity is probably limited by seismic noise, as it alignes with FPMI DARM sensitivity (orange curve; measured in 40m/17468).
 Attachemnt #2 and #3 show estimate of LO phase noise contribution to MICH sensitivity in BH55 case and BH44 case. The coupling was estimated by measuring a transfer fuction from BH55_Q/BH44_Q to MICH_W_OUT. As there was significant coherence in 30200 Hz region in BH55 case, and 30100 Hz in BH44 case, transfer function value in that regions was used to estimate the coupling.
 The coupling was estimated to be the following
2e10 m/count for BH55_Q to MICH_W_OUT (0.035 m/m using BH55_Q calibration factor to LO1 motion of 1.76e8 counts/m)
2e11 m/count for BH44_Q to MICH_W_OUT
 Diaggui file: /opt/rtcds/caltech/c1/Git/40m/measurements/LSC/MICH/MICH_Sensitivity_Live.xml
Next:
 Calibrate BH44_Q to LO1 motion
 Measure transfer function from LO1 motion to BHD_DIFF under BH44 and BH55
 Find out the cause of 50 Hz bump in LO phase noise
 Compare LO phase noise coupling with simulations 
Attachment 1: MICH_Sensitivity_20230320.pdf


Attachment 2: MICH_Sensitivity_20230320_BH55Contribution.pdf


Attachment 3: MICH_Sensitivity_20230320_BH44Contribution.pdf


17515

Tue Mar 21 18:41:12 2023 
Alex  Update  IMC  Dither Lines set on MC1, MC2, MC3 for the night  With Anchal's help, I have setup dither lines for Rana on MC1,2,3 that will be running overnight. The oscilations were set on MC1,2,3, oscillator screens.
The following table describes the current setup:
Mirror 
Frequency 
Amplitude 
MC1 
21.12 Hz 
2000 
MC2 
25.52 Hz 
1000 
MC3 
27.27 Hz 
2500 
These frequencies and amplitudes were set on LOCKIN1 for each MC1,2,3. The output filters matrix for MC1,2,3 was also updated to reflect the degree of freedom being tested: PITCH.
The frequencies were picked to avoid the dewhitening frequency: 28Hz, and the Bounce/Roll frequencies: 16 Hz & 24 Hz. Furthermore, decimal value frequencies were utilized to avoid the multiples of 1 Hz.
The oscilators were originally started at 1363480200 and will be turned off at 1363535157.
See attachment 1 for the plot of the power spectrum. This test is done to find the beam offset for pitch. 
Attachment 1: 21032023_Dither_lines_plot

17516

Wed Mar 22 15:51:44 2023 
Alex  Update  IMC  Beam offset calculation for MC1,2,3 from dither results  I have organized the resulting data from running dither lines on MC1,2,3. The data has been collected from diaggui as shown in attachment 1.
Mirror 

Avg Re (+/ 1000) 
Avg Im (+/ 1000) 
Peak Power () 
Cts/urad 
MC1 
21.12 
7000 
4000 
8062 
12.66 
MC2 
25.52 
13000 
10000 
16401 
6.83 
MC3 
27.27 
4000 
600 
4044 
11.03 
Next using the following equations we can find :
Where is the change in length in result of the dithering and is the overall change in beam spot position
Delta L can be calculated by:
where is the peak power of the line frequency and is found by taking the square root of the magnitude of the Real and imaginary terms, is frequency the laser light is traveling at (281 THz) and is the lenght of the IMC (13.5 meters).
can then be calculated by:
where is the angle at which the mirror was shaken at a given frequency. We can find by converting the amplitude of the frequency that the mirror was shaken at and converting it into radians using the conversion constants found here: 17481.
is then shown to be found by this angle diveded by the line frequency.
The final values are calculated and displayed bellow:
Mirror 




MC1 
157.9 urad 
0.35 urad 
0.38 nm 
1.08 mm 
MC2 
146.4 urad 
0.23 urad 
0.78 nm 
3.39 mm 
MC3 
226.7 urad 
0.31 urad 
0.19 nm 
0.61 mm 

Attachment 1: 22032023_Dither_lines_demod_MC1_2112.pdf


17517

Wed Mar 22 18:38:54 2023 
Paco  Summary  BHD  "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"  [Paco, Yehonathan]
I took over the finesse calculations Yehonathan had set up for BHD. The notebook is here and for this post I focused on simulating what we might expect from our single RF vs dual RF sensors (55 MHz and 44 MHz respectively) in terms of LO phase control.
The configuration is simple, only MICH is included (no ETMs, no PRC, no SRC). The LO phase is changed by scanning LO1, the differential loss is changed by scanning the ITMXHR loss parameter (nominally at 25 ppm), and the microscopic DARM offset is changed by scanning the BS position by + 6 nm.
Finesse estimates the sensor response by taking the demodulated sideband magnitude (BH55, BH44) with respect to a 1 Hz LO1 signal modulation. This can be done for a set of LO phase angles so as to get the nominal LO phase angle where the response is maximized.
I first replicated the plots from [elog17170] for the two sensors in question. This is just done as a sanity check and is shown in Attachment #1. This plot summarizes our expectation that the single RF sideband sensor should have a peak response to the LO phase around 90 deg away from the nominal BHD readout phase angle (0 deg in this plot). In contrast, the double RF demodulation scheme has a peak response around the nominal LO phase angle.
Attachment #2 looks at a family of similar plots representing differential loss changes between the two MICH arms. We tune this by changing the ITMX loss in finesse, and then repeat the calculation as described above. It seems that for the simple MICH, differential loss of ~ 10000 ppm does not impact the nominal LO phase angle where the responses are maximized for either sensor (note however that the response magnitude maybe changes for single RF sideband sensing at extremely high differential loss).
Finally, and most interestingly Attachment #3 looks at a family of similar plots representing a set of microscopic DARM offsets (+ 6 nm). This is tuned by changing the BS position ever so slightly, and the same calculation is repeated. In this case, the nominal LO phase angle does change, and it changes quite a lot for the single RF demod. It looks like this might be enough to explain how we can sense the LO phase angle with a single RF sideband, but I think the next interesting point would be to simulate the effect of contrast defect by changing the ITM RoCs (to scatter into HOMs) or the nonthermal ITM lenses (to probe the TEM00 contrast defect effect). Any comments / feedback at this point are welcome, as we move forward into other configurations where more serious thermal effects might be introduced (PRMI). 
Attachment 1: LOphase_sensors.pdf


Attachment 2: LOphase_sensors_loss.pdf


Attachment 3: LOphase_sensors_darmoffset.pdf


17518

Thu Mar 23 14:20:29 2023 
Koji  Summary  BHD  "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"  This is interesting. With the FPMI, the DARM phase shift is enhanced by the cavity. Therefore, I suppose the effect on the BH55 is also going to be enhanced (i.e. a much smaller displacement offset causes a similar LO phase rotation).

17519

Thu Mar 23 16:21:10 2023 
rana  Update  IMC  Beam offset calculation for MC1,2,3 from dither results  I have changed the MC SUS output matrices by a few % for some A2L decoupling  if it causes trouble, please feel free to revert.
Anchal came to me and said, "I think those beam offsets are a bunch of stinkin malarkey!", so I decided to investigate.
Instead of Alex's "method" of trusting the actuator calibration, I resolved to have less systematics by adjusting the SUS output matrices ot minimize the A2L and then see what's what vis a vis geometry.
The attached screenshot shows you the measurement setup:
 copy the DoF vector from DoF column into the LOCKIN1 column.
 Turn on the OSC/LOCKIN for the optics / DoF in question (in this example its MC2 PITCH)
 Monitor the peak in the MC_F spectrum
 Also monitor the mag and phase of the TF of MC_F/LOCKIN_LO
 use the script stepOutMat.py to step the matrix
Next I'm going to modify the script so that it can handle input arguments for optic/ DOF, etc.
FYI, the LOCKIN screens do have a TRAMP field, but its not on the screens for some reason . Also the screens don't have the optic name on them. :
SUS>caput C1:SUSMC2_LOCKIN1_OSC_TRAMP 3
Old : C1:SUSMC2_LOCKIN1_OSC_TRAMP 0
New : C1:SUSMC2_LOCKIN1_OSC_TRAMP 3
After finishing the tuning of all 3 IMC optics, I have discovered that 27.5 Hz is a bad frequency to tune at: the Mc1/MC3 dewhtiening filters have a 28 Hz cutoff, so they all have slightly different phase shifts at 2728 Hz due to the different poles due to tolerances in the capacitors (probably).
*Also, I am not able to get a real zero coupling through this method. There always is an orthogonal phase component that can't be cancelled by adjusting gains. On MC3, this is really bad and I don't know why.

Attachment 1: TuninMC2OutMatA2Lbeaucoup.png


Attachment 2: IMCA2Lnomore_cawcaw.png


17520

Thu Mar 23 17:47:53 2023 
Paco  Update  NoiseBudget  LO phase noise budget (BH55_Q)  I drafted a calibrated LO Phase noise budget using diaggui whose template is saved under /opt/rtcds/caltech/c1/Git/40m/measurements/BHD/LO_PHASE_cal_nb.xml which includes new estimates for laser frequency and intensity noises at the LO phase when MICH is locked (whether they couple through MICH or the LO path is to be determined with noise coupling measurements in the near future, but we expect them to couple through the LO phat mostly).
Attachment #1 shows the result.
Laser Frequency Noise
To calibrate the laser frequency noise contribution, I used the LO PHASE error point away from the control bandwidth (~ 20 Hz) and the calibrated C1:IOOMC_F control point (in Hz) which should represent the laser frequency noise above 100 Hz. and dithered MC2 at frequencies around to 130, 215, and 325 Hz to match the LO phase error point with the MC_F signal. I was expecting to use a single 0 Hz pole + gain (to get the phase equivalent of the laser frequency noise) but in the end I managed to calibrate with a single gain of 3.6e7 rad/Hz and no pole. Since the way the laser frequency noise couples into our BHD readout may be complicated (especially when using BH55 RF sensor) I didn't think much of this for now.
Laser Intensity Noise
For the intensity noise, I followed more or less a similar prescription as for laser frequency noise. This time, I used the AOM in the PSL table to actuate on the 0th order intensity going into the interferometer. Attachments #23 show the connection made to the RF driver where I added a 50 mVpp sine (at an offset of 0.1 V) excitation in the AM port to inject intensity noise calibration lines at 215 and 325 Hz and matched the LO_PHASE error point with the BHDC_SUM noise spectrum. 
Attachment 1: lophase_cal_nb_20230322.png


Attachment 2: PXL_20230323_202125206.jpg


Attachment 3: PXL_20230323_194150923.jpg


17521

Thu Mar 23 19:15:39 2023 
yuta  Summary  LSC  PRMI locked using REFL55  [Paco, Yuta]
We locked PRMI in sideband using REFL55_I and REFL55_Q.
Lock is not quite stable probably due to alignment fluctuations, and power recylicing gain is breathing.
PRMI preparations:
 We aligned PRM using PRY (PRMITMY) cavity. Aligning PRM to oplev QPD center or last PRM alignment values in May 2022 (! see 40m/16875) didn't work, but we were in the middle of these two, both in pitch and yaw.
 After this, we centered PRM oplev, aligned REFL camera, POP RFPD (which provides POP22, POP110, and POPDC), and REFL11.
PRY/PRX locking:
 PRY/X was locked using REFL55_I or REFL11_I. Locking configuration which gives UGF of ~100 Hz was as follows
REFL55_I (24 dB whitening gain, 76.02 deg demod angle) C1:LSCPRCL_GAIN=0.03
REFL11_I (18 dB whitening gain, 32.55 deg demod angle) C1:LSCPRCL_GAIN=0.8
FM4,5 used for acquisition, FM1,2,6,9 turned on triggered.
 Attachment #1 is the measured OLTF when PRY was locked.
 When PRY is flashing, ASDC_OUT, POPDC_OUT, POP22_I, POP11_Q flashes upto 0.33, 1000, 30, 80, respectively.
PRMI locking:
 PRMI was locked using REFL55_I for PRCL and REFL55_Q for MICH using the following configurations to give UGF of ~100 Hz for both DoF.
PRCL
REFL55_I (24 dB whitening gain, 76.02 deg demod angle) C1:LSCPRCL_GAIN=0.03
FM4,5 for acquisition, FM1,2 turned on triggered using POPDC.
Actuating on 1 * PRM
MICH
REFL55_Q (24 dB whitening gain, 76.02 deg demod angle) C1:LSCMICH_GAIN=+0.9
FM4,5 for acquisition, FM1,2 turned on triggered using POPDC.
Actuating on 0.5 * BS  0.275 * PRM
 REFL55 demodulation phase was the same as FPMI and PRY. We checked this is roughly enough by measuring the sensing matrix to minimize PRCL component in Q.
 MICH actuation of PRM/BS ratio was roughly tuned by minimizing the sensing of MICH component in REFL55_I.
 PRCL and MICH gain was estimated by measuring the amplitude of error signals in PRY or PRMmisalgined MICH, and comparing that in PRMI.
 Attachment #2 shows the screenshot of the configuration.
 Attachment #3 and #4 are measured OLTF for PRCL and MICH.
 Attachment #5 shows the time series data when PRMI is locked.
Next:
 Tune PRM local damping
 Tune REFL55 demodulation phase better by measuring the sensing matrix
 Measure PRM actuation efficiency to check what is the right BS/PRM balancing
 Estimate power recycling gain and compare with expectations
 Lock PRMI using REFL11, AS55
 PRMI BHD 
Attachment 1: Screenshot_20230323_155825_PRY_OLTF.png


Attachment 2: Screenshot_20230323_184825_PRMIlocking.png


Attachment 3: Screenshot_20230323_184125_PRCL_PRMI.png


Attachment 4: Screenshot_20230323_184055_MICH_PRMI.png


Attachment 5: Screenshot_20230323_184412_PRMISB.png


17522

Fri Mar 24 12:54:51 2023 
yuta  Summary  LSC  Actuator calibration of PRM using PRY  PRM actuator was calibrated using PRY by comparing the actuation ratio between ITMY.
It was measured to be
PRM : 20.10e9 /f^2 m/counts
This is consistent with what we have measured in 2013! (40m/8255)
Method:
 Locked PRY using REFL55_I using the configuration described in 40m/17521 (UGF of ~100 Hz)
 Measured transfer function from C1:LSC(ITMYPRM)_EXC to C1:LSCPRCL_IN1
 Took the ratio between ITMY actuation and PRM actuation to calculate PRM actuation, as ITMY actuation is known to be 4.90e9 /f^2 m/counts (40m/17285).
Result:
 Attachment #1 is the measured TF, and Attachment #2 is the actuator ratio PRM/ITMY.
 The ratio was 4.10 on average in 70150 Hz region, and PRM actuation was estimated to be 4.90e9 * 4.10 /f^2 m/counts.
MICH actuator for PRMI lock:
 When BS moves in POS by 1, BSITMX length stays the same, but BSITMY length changes by sqrt(2), so MICH changes by sqrt(2) and PRCL changes by sqrt(2)/2.
 So PRM needs to be used to compensate for this, and the ratio will be BS + k * PRM, where
k = 26.54e9/sqrt(2) / 20.10e9 * sqrt(2)/2 = 0.66
 So, good MICH actuator will be 0.5 * BS  0.33 * PRM, which is not quite consistent with the rough number we had yesterday (0.275; 40m/17521), but agrees with the Gautam number (0.34; 40m/15996).
 PRMI sensing matrix for REFL55 needs to be checked again.
Summary of actuation calibration so far:
They are all actuator efficiency from C1:LSC{$OPTIC}_EXC
BS : 26.54e9 /f^2 m/counts in MICH (40m/17285)
ITMX : 4.93e9 /f^2 m/counts (40m/17285)
ITMY : 4.90e9 /f^2 m/counts (40m/17285)
LO1 : 26.34e9 /f^2 m/counts (40m/17285)
LO2 : 9.81e9 /f^2 m/counts (40m/17285)
AS1 : 23.35e9 /f^2 m/counts (40m/17285)
AS4 : 24.07e9 /f^2 m/counts (40m/17285)
ETMX : 10.91e9 /f^2 m/counts (40m/16977, 40m/17014)
ETMY : 10.91e9 /f^2 m/counts (40m/16977)
MC2 : 14.17e9 /f^2 m/counts in arm length (40m/16978)
MC2 : 5.06e9 /f^2 m/counts in IMC length (40m/16978)
MC2 : 1.06e+05 /f^2 Hz/counts in IR laser frequency (40m/16978)
PRM : 20.10e9 /f^2 m/counts (40m/17522) 
Attachment 1: PRMActuatorTF.png


Attachment 2: PRMActuatorRatio.png


17523

Fri Mar 24 15:05:41 2023 
yuta  Summary  LSC  PRMI sensing matrix and RF demodulation phase tuning  PRMI sensing matrix was measured under PRMI locked with REFL55_I and Q.
MICH actuator is 0.5*ITMX0.5*ITMY (to have more pure MICH, according to 40m/15996) and PRCL actuator is PRM.
RF demod phases seem to be good within a degree or so to minimize PRCL component in Q.
Sensing matrix with the following demodulation phases (counts/m)
{'AS55': 2.1, 'REFL55': 76.02, 'REFL11': 32.63833493469488}
Sensors MICH @311.1 Hz PRCL @313.31 Hz
AS55_I (+0.31+/1.48)e+09 [90] (+6.56+/2.23)e+10 [0]
AS55_Q (3.49+/0.87)e+08 [90] (+4.62+/1.80)e+09 [0]
REFL55_I (1.52+/5.61)e+09 [90] (+3.21+/1.36)e+11 [0]
REFL55_Q (+8.77+/0.46)e+09 [90] (+5.01+/3.63)e+09 [0]
REFL11_I (0.23+/1.92)e+08 [90] (+1.13+/0.47)e+10 [0]
REFL11_Q (+0.39+/2.14)e+07 [90] (4.00+/9.79)e+07 [0]
Phase for AS55 to minimize PRCL in Q is 6.14+/2.08 deg (4.04+/2.08 deg from current value)
Phase for REFL55 to minimize PRCL in Q is 76.91+/0.75 deg (0.89+/0.75 deg from current value)
Phase for REFL11 to minimize PRCL in Q is 32.44+/0.50 deg (0.20+/0.50 deg from current value)
Next:
 Lock PRMI in carrier
 PRG is not so stable; Measure gfactor of PRC using KakeruGupta method (40m/8235) 
