[Sheila, Gabriele]

As suggested by Keita during the morning meeting, we checked the IM4 transmitted beam coming from the PRM reflection, on the in-air table. We dumped both beams on the table, and this improved a lot the situation. When the PRM is aligned, the noise on the ISS diodes doesn't increase much anymore. However, there is still a small worsening at 18 Hz, so maybe in the future we might want to better dump the beam at the level of the upper mirror into the enclosure.