Rahul, (Austin and Camilla for in air measurements taken in Feb 2022)

There are some concerns about the health of OPO in HAM7 chamber after Dhruva found some scattering noise above 1kHz (see alog 64192). Today I took top to top transfer function measurements and then compared it against previous measurements (May 2022 in UHV; Feb 2022 in air).

Plot01 attached bellow shows that nothing has changed from Feb 2022 till now: blue trace is from todays measurements, magenta color is for the data taken in May under UHV and orange is in-air (which is a bit noisy and is expected) measurements.

As one can see that for some of the DoF, the measured data is different (magnitude and frequency) from the model (blue trace), hence I pulled out the results from LLO  (see Stuart's alog 60665) which is attached blow. If we compare LHO vs LLO for OPO then we find that both SUS are performing very similar and once again some of dof doesn't match with the model.

Hence I can confirm that OPO is healthy and there is no rubbing - maybe one should update the model data.

We can also check the osem spectra to rule out any excess noise contributions from the osems.

The templates are as follows,

/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Data

Feb 2022 (in-air taken by Austin and Camilla)

2022-02-28_1200_H1SUSOPO_M1_WhiteNoise_L_0p02to50Hz.xml
2022-02-28_1200_H1SUSOPO_M1_WhiteNoise_P_0p02to50Hz.xml
2022-02-28_1200_H1SUSOPO_M1_WhiteNoise_R_0p02to50Hz.xml
2022-02-28_1200_H1SUSOPO_M1_WhiteNoise_T_0p02to50Hz.xml
2022-02-28_1200_H1SUSOPO_M1_WhiteNoise_V_0p02to50Hz.xml
2022-02-28_1200_H1SUSOPO_M1_WhiteNoise_Y_0p02to50Hz.xml

May 2022 under UHV
2022-05-03_1800_H1SUSOPO_M1_WhiteNoise_L_0p02to50Hz.xml
2022-05-03_1800_H1SUSOPO_M1_WhiteNoise_P_0p02to50Hz.xml
2022-05-03_1800_H1SUSOPO_M1_WhiteNoise_R_0p02to50Hz.xml
2022-05-03_1800_H1SUSOPO_M1_WhiteNoise_T_0p02to50Hz.xml
2022-05-03_1800_H1SUSOPO_M1_WhiteNoise_V_0p02to50Hz.xml
2022-05-03_1800_H1SUSOPO_M1_WhiteNoise_Y_0p02to50Hz.xml

August 2022

2022-08-02_1600_H1SUSOPO_M1_WhiteNoise_L_0p02to50Hz.xml
2022-08-02_1600_H1SUSOPO_M1_WhiteNoise_P_0p02to50Hz.xml
2022-08-02_1600_H1SUSOPO_M1_WhiteNoise_R_0p02to50Hz.xml
2022-08-02_1600_H1SUSOPO_M1_WhiteNoise_T_0p02to50Hz.xml
2022-08-02_1600_H1SUSOPO_M1_WhiteNoise_V_0p02to50Hz.xml
2022-08-02_1600_H1SUSOPO_M1_WhiteNoise_Y_0p02to50Hz.xml