Sheila updated the ETMY ring heater again to 1.5 W, and it looks like ETMY mode 20 phase has flipped back, and a damping gain of -1 is working once again.

It appears that gains of both -1 and +1 are not damping the mode now. Corey is trying different phase filters.

I took 5-200hz matlab tfs this morning to compare to the  2 previous measurements above. It seems that the damping is quite effective now. I will try to look at the effect on the isolation filter design, maybe we can get some of the loop gain back. It would still be better to move these modes up above 100hz if possible.

Just want to add a note that all three locks from last night were nearly the exact same length, 1:51, and the locklosses are all tagged with "PI monitor". A ring heater was changed yesterday, 85514, which may have caused this problem.

Additionally, each of the 3 locklosses were from PI28/29 according to VerbalAlarms (the Ring Heater change yesterday was made to address PI24 which riddled our 7hr lock for the last hour before the ultimate lockloss).

While we have been running PIMON live on nuc25, it appears the data from the lockloss hasn't been saved. The newest file in the /ligo/gitcommon/labutils/pimon/locklosses folder is from December 2024. I'm not sure what's going on. We think our problem is an 80 kHz PI, so this would be useful data to have.

I altered the code to plot in mm and the constant is 4.4 V/mm.

D'oh I read the scale on the translation stage wrong so the x readings are actually lower by a factor of 10.

This makes the slope 44.1 V/mm which is more in line with the 65.11 V/mm Mayank and Shiva found for the QPD calibration here.

Ours could be different because we have a slightly different beam size and we moved the QPD in its housing to centre it which could have changed X to Y coupling in the QPD readout.

This implies our beam diameter on the QPD is around 0.4mm which makes a lot more sense considering the diode is 3mm!

As a cross-check we used the QPD 'bullseye' readout unit and Rahul changed the translation stage in yaw and we measured the beam dropping from 10400 counts in the middle of the QPP to 100s of counts at the edges.

diode size ~ ((0.49-0.365)*0.0254*1000) = 3.175 mm.

I redid the graphs for the horizontal motion of the input beam to X motion on the QPD with better labels (first attached graph) and did a fit for the Y data on the QPD collected at each horizontal position of the input beam (second attached graph). The third graph attached is comparing both fits on one graph.

If we take into account the input beam horizontal axis is not aligned with the QPD, we can work out the resultant calibration relative to the mirror displacement as:

V change along mirror displacement axis = sqrt((change V in X)^2 + (change V in Y)^2)

Calibration = V change along mirror displacemnt axis/change in mirror position

= 4.644 V/mm.

angle of QPD horizontal axis with mirror displacement axis = tan^-1(Voltage change V in Y/ Voltage change in X) = 38.8 degrees.

I got the above caluclation of the QPD calibration in the horizontal direction wrong as I use the total change in voltage we measured across the whole range of horizontal scan and not just the linear region where the beam is close to centred on the QPD.

The horizontal beam scan calibration is actually:

sqrt(11.8^2 + 44.1^2) = 10.6 V/mm

with an angle of tan^-1(11.8/44.1) = 14.9 degrees to the X direction on the QPD.

NOTE:  Well, after getting H1 back to 60W, the violins are not rung up and better than how they looked at the end of my shift yesterday.

(Sheila & Todd are now looking at the Squeezer & I returned H1 to be able to "Observe WITH Squeezing".)

I noticed ETMX mode1 has been high ever since coming back from maintenance yesterday and we usually don't damp this mode. I took a high res spectra to confirm that it was this mode and not another close line causing this and it was so I tried to find some damping settings.

Nothing worked all that well, some tentative new settings are FM1+FM2+FM10 G=-50.

Here's the characterization data and fit results for S1100168, assigned to PRM M1's T1T2T3LF OSEMs (what Fil refers to as just "PRM TOP" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1100168_PRM_M1_T1T2T3LF_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
PRM      M1       S1100168         CH1                T1           0.0969 : 5.30   120.10        zpk([5.3],[0.0969],1,"n")
                                   CH2                T2           0.0950 : 5.20   120.25        zpk([5.2],[0.095],1,"n")
                                   CH3                T3           0.0950 : 5.18   120.25        zpk([5.18],[0.095],1,"n")
                                   CH4                LF           0.0940 : 5.15   120.00        zpk([5.15],[0.094],1,"n")

The attached plot and machine readable .txt file are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

Even though I've fit for the transimpedance gain, I've elected *not* to include a gain in the foton design string relative to "ideal," as there are more scale factors in play that determine the overall [(meters)/(ADC cts)] scale in the calibration of the OSEMs (LED light power, PD response, any cable loss, ADC channel gain, etc.). Determining this overall scale is better left to different methods, a la LHO:84548, which we (eventually) anticipate doing for all SUS with ECR E2400330 upgraded satamps.

Here's the characterization data and fit results for  S1100173 , assigned to PRM/PR3 M1's RTSD/T1T2 OSEMs (what Fil refers to as just "PRM/PR3" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1100173_PRMPR3_M1_RTSDT1T2_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
PRMPR3   M1       S1100173         CH1                RT           0.0969 : 5.3    120.00        zpk([5.3],[0.0969],1,"n")
                                   CH2                SD           0.0955 : 5.22   120.00        zpk([5.22],[0.0955],1,"n")
                                   CH3                T1           0.0975 : 5.35   119.75        zpk([5.35],[0.0975],1,"n")
                                   CH4                T2           0.0975 : 5.33   120.25        zpk([5.33],[0.0975],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

Here's the characterization data and fit results for  S1100183 , assigned to PR3 M1's T3LFRTSD OSEMs (what Fil refers to as just "PR3" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1100183_PR3_M1_T3LFRTSD_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
PR3      M1       S1100183         CH1                T3           0.0950 : 5.19   120           zpk([5.19],[0.095],1,"n")
                                   CH2                LF           0.0945 : 5.17   120           zpk([5.17],[0.0945],1,"n")
                                   CH3                RT           0.0940 : 5.14   120           zpk([5.14],[0.094],1,"n")
                                   CH4                SD           0.0955 : 5.24   120           zpk([5.24],[0.0955],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

Here's the characterization data and fit results for  S1000291 , assigned to BS M1's F1F2F3LF OSEMs (what Fil refers to as just "BS TOP" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1000291_BS_M1_F1F2F3LF_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
BS       M1       S1000291         CH1                F1           0.096 : 5.19    121.50        zpk([5.19],[0.096],1,"n")
                                   CH2                F2           0.096 : 5.23    120.75        zpk([5.23],[0.096],1,"n")
                                   CH3                F3           0.096 : 5.26    120.00        zpk([5.26],[0.096],1,"n")
                                   CH4                LF           0.095 : 5.2     120.00        zpk([5.2],[0.095],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

Here's the characterization data and fit results for  S1100066 , assigned to BS M1's RTSDxxxx OSEMs (with the 2x "xx" representing the unused channels not connected to anything in-vacuum. Fil refers to this as just "BS RT/SD" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1100066_BS_M1_RTSDxxx_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
BS       M1       S1100066         CH1                RT           0.0960 : 5.19   121.50        zpk([5.19],[0.096],1,"n")
                                   CH2                SD           0.0940 : 5.11   120.75        zpk([5.11],[0.094],1,"n")
                                   CH3                xx           0.0935 : 5.12   120.25        zpk([5.12],[0.0935],1,"n")
                                   CH4                xx           0.0965 : 5.26   120.50        zpk([5.26],[0.0965],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

Here's the characterization data and fit results for  S1000284 , assigned to SR3 M1's T1T2T3LF OSEMs (Fil refers to this as just "SR3 Top" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1000284_SR3_M1_T1T2T3LF_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
SR3      M1       S1000284         CH1                T1           0.0960 : 5.25   120.1         zpk([5.25],[0.096],1,"n")
                                   CH2                T2           0.0950 : 5.2    120.1         zpk([5.2],[0.095],1,"n")
                                   CH3                T3           0.0960 : 5.27   120.1         zpk([5.27],[0.096],1,"n")
                                   CH4                LF           0.0945 : 5.16   120.5         zpk([5.16],[0.0945],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

Here's the characterization data and fit results for  S1000290 , assigned to SR3/SRM M1's RTSD/T1T2 OSEMs (Fil refers to this as just "SR3/SRM" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
        plotresponse_S1000290_SR3SRM_M1_RTSDT1T2_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
SR3/SRM  M1       S1000290         CH1                RD           0.0955 : 5.21   120.1         zpk([5.21],[0.0955],1,"n")
                                   CH2                SD           0.0940 : 5.13   120.5         zpk([5.13],[0.094],1,"n")
                                   CH3                T1           0.0930 : 5.07   120.5         zpk([5.07],[0.093],1,"n")
                                   CH4                T2           0.0950 : 5.2    120.1         zpk([5.2],[0.095],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

Here's the characterization data and fit results for  S1100068 , assigned to SRM M1's T3LFRTSD OSEMs (Fil refers to this as just "SRM" above).
The data was taken per methods described in T080062-v3.
The data was processed and fit using 
    ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
         plotresponse_S1100068_SRM_M1_T3LFRTSD_20250630.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are
Optic    Stage    Serial_Number    Channel_Number     OSEM_Name    Zero_Pole_Hz    R_TIA_kOhm    Foton_Design
SRM      M1       S1100068         CH1                T3           0.094 : 5.14    120.10        zpk([5.14],[0.094],1,"n")
                                   CH2                LF           0.095 : 5.18    120.25        zpk([5.18],[0.095],1,"n")
                                   CH3                RT           0.096 : 5.23    120.75        zpk([5.23],[0.096],1,"n")
                                   CH4                SD           0.096 : 5.29    119.00        zpk([5.29],[0.096],1,"n")

The attached plot and machine readable .txt file version of the above table are also found in
${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/

See above LHO:85504 comment as to why an account of the fit transimpedance was not included in the foton design string gain.

After the maintenance I tweeked the AOM to increase the diffraction efficiency. The nominally, the diffraction should be above 70% efficiency, which translates to 1.34 W from the *Maestro*. My procedure went as follows:

1. Set the OFS offset to the recorded max: 7.2 V on V2 of the HP power supply on the upper right (when looking from the front)
   • Once the offset is set, block the beam (be safe!)
2. Placed the high-power head (HPH) before the AOM on the Tx module
   • Zero-ed the readout and then unblock the beam.
   • Readout: 1.92 W (consistent with maintenace done the day before).
3. Placed HPH before the wedged beamsplitter
   • Readout: 1.24 W (consistent with maintenace done the day before).
4. So far, everything is consistent with the maintenance. We can now adjust the AOM.
   • The AOM is placed on a New port stage, following the documentation for this component, the bottom screws will adjust the Y axis (height) and the top screws will adjust the X axis (angle of incidence).
5. Adjusted Y1 and Y2 -- bottom left and bottom right screws, respectively. A counter-clockwise adjustment of each screw, to about one turn, increased the output to 1.28 W.
6. Adjusted X1 and X2 -- top left and right screws -- to reach 1.30 W. Fine adjustments could not get a higher output.
7. Returned offset to operating value of 3.42 V on power supply.

AOM alignment increased the efficiency to 67%, a gain of 3%.

This was HAM1 not ISCT1