Virgo Logbook

Reports 1-1 of 1

AdV-TCS (Acoustic enclosures)

bersanetti, corubolo, lumaca, mantovani, nardecchia, spinicelli, was - 20:56 Tuesday 22 September 2026 (69794)

Revert to the Friday TCS configuration

In agreement with the commissioning crew, I reverted all the steps performed over the weekend to return to the last configuration we had on Friday (STEP 8, entry 69755) when the lock acquisition seemed to be reliable. The main goal was to try HWS-DET acqusitions in order to veirfy the situation of PAs on the NI mirror.

Activity completed at 10.30 UTC.

Here the TCS settings:

		CH [W]	INNER DAS [W]	OUTER DAS [W]
W	on the ITF	0.044	0	1.08
W	on the pickoff	0.272	0	0.180
N	on the ITF	0.040	0.18	0.72
N	on the pickoff	0.247	0.029	0.118

At the end of the transient, during the afternoon shift, we resumed the lock acquisition attempts, but the same issues observed yesterday persisted.

Comments to this report:

mantovani, corubolo, spinicelli, gherardini, was, bersanetti, nardecchia - 21:15 Tuesday 22 September 2026 (69796)

- we reverted all the locking parameters to friday 18th at 12 UTC

the carm null 1f was not reachable (no loop oscillations), so we started to remove part to try to survive

- removed COMMp, CARM slow, alpha and Soft

the lock was killed by instabilities on the dark fringe, so Michal raised the shutter treshold to 0.027

we then tryed to lock with SR misaligned (-2urad ty) and we increased the jumps rate, see Figure 1.

The lock behavior is not predictable and no loop oscillations are present. It could be that we are too close to the cavity instability.

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