The following report has been submitted to the On-call interface.
On-call events -> Interferometer Sensing & Control
Title: ITF recovery
Author(s): mpinto, bersanetti
Called at: 00:00, , by: Alarm or monitoring system |
Remote intervention: Started: ; Ended: |
On-site intervention: Started: 17:00, 25-10-2024; Ended: 23:05, 25-10-2024 |
Status: Resolved |
Operator when issue resolved: Gherardini |
Details:
Today, after the morning INJ shift, we had troubles with the lock acquisition, at first during the handoff from DRMI 1f to 3f, which was unlocking for a 6 Hz oscillation present in MICH and SRCL.
To get past the step, together with Diego we had to tune the B2 169MHz demodulation phase of about -0.6 rad of delta. We had to propagate the same amount of tuning along the several step of the acquisition.
We checked all the phases of the other loops. We tuned also:
DARM B1p 56 MHz at every step, reducing it of the same -0.5 rad.
We fine tuned DIFFp phases (also on B1p56 MHz).
We proceeded with the acquisition up to LN3, but during the ACQUIRE of LN1 we noticed some misbehavior of the FModErr tuning, whose phase was mistuned as well.
We reached LN3 SQZ but in a very bad noisy state.
We contacted Matthieu in order to check it and eventually we manually unlock to verify that also the tuning at the very first step of the acquisition was good.
After some investigation he and Piernicola found out that the perturb cable if the IMC rampeauto has not been replugged correctly. Fabio plugged it and we start the relock of the ITF.
We reverted almost all the modification done previously. We managed to reach CARM null 1f with no issue.
Relock up to LN3 in progress.
* Note that any files attached to this report are available in the On-call interface.