See also alog 26948. I repeated the L2 noise measurements described in alog 26948 for ETMX L2 and ETMY L2, as well as BS M2. For completeness I also added the ITM noise to this log.

The measurement conditions are the same as in alog 26948 (Acq Off, LP On, small 3kHz length drive).

Conclusion: no suspicius noise on the L2s (or the BS M2).

Plots 1-5 (in that order): ETMX, ETMY, ITMX, ITMY, BS

Plot 6: projection of the noise for the four main test masses.

Remark: ETMY features a 10Hz line, as well as a smaller 30Hz line. They seems to be real, and they have a different strenghts in the 4 coils.