The recovery of the injection took longer than usual because when we unblocked the beam, dumped as usual at the output of the PMC with the PMC in scan, the system was unstable with the PMC and IMC unlocking continuosly.

We did all the usual checks to exclude the different loops (we opened the PSTAB, the IMC AA, the RFC, checked the IMC loop working points). At the end the IMC restarted to lock.

We thought that the increase of temperature on the LB had produced a horizontal misalignment at the output of the NEOVAN (plot 1), but since we did not remember such kind of issue, we looked back in the data of the 3rd of Feb (beam blocked to work on EIB suspension) and we found out that we had similar increase of temperature and drift of the NEOVAN, but that time the IMC relocked straight (plot 2).

We measured the OLTF of the IMC (both digitally, and I forgot the noise on, this is one of the reason why the ISC crew had problems with the relock) and analogically. The phase margin was lower than the last times we measured it (9° instead of 17°) (plot 3)

At the end we checked the Fmoderr and we left the system as it was before the shift. We did not understand yet the origin of the issue we encountered.