Today with the help of Matteo we profited of the LN3 to check for scattered light on the squeezing bench with an IR viewer without detuning the SDB1 waveplate.

We could see that the beam was not well centered on the two steering mirrors. We could see some scattered light on the post of a steering mirror on the camera's path (the mirror on the corner of the bench).

Despite some trials, I didn't manage to tune the squeezer alignment (closing the dithering loop made the M1_X modulation vanished and gave a huge kick to it).

At 15h07 UTC we put a beam dump after the mirror close to SDB1.

When looking at H_rec the 45Hz bump disapperead as well as the ~20Hz bump decreased (Fig. 1). This is in good agreement with the results of yesterday shift

The range slightly improved (Fig. 2)