Virgo Logbook

Reports 1-1 of 1

AdV-TCS (Ring Heater)

nardecchia, mantovani, spinicelli - 15:39 Monday 26 February 2024 (63405)

NE RH tuning

This morning we found the ITF in LN3.

Discussing with Fiodor, we decided to proceed with the ETM differential tuning that started Friday (63391).

We manually unlocked and relocked to test the lock acquisition with SR RH at 7 W.

Everything went well.

Thus, in LN3, at 10.12 UTC the NE RH power has been changed.

We decreased the NE RH power from 4.7 W (13.2 V) to 4.5 W (12.94 V).

After that the ITF unlocked for no obvious reason.

The ITF relocked at 10.39 UTC and it unlocked at 13.04 UTC, probably for the bad weather.

At 13.55 the ITF again reached LN3, but it unlocked soon after.
The ITF main signals during the shift are shown in fig.1. The effect of the NE RH power change will be verified in the next TCS shift.

Images attached to this report

Comments to this report:

mantovani, spinicelli, nardecchia - 17:11 Monday 26 February 2024 (63406)

Few comments from ISC side:

- the SR ty gain has been increased from -0.003 to -0.008 to speed up the convergence of the SR wp. It worked fine but we will test again if the strong value on MICH set point was due to the fast transient or the RH tuning.

- the DARM 74Hz line showed low coherence to be able to tune the DARM gain (due to the lowering of the line and the bad weather condition) then the DARM ugf was increasing up to 100Hz. (still stable). We lowered by hand and the line will be increased of a factor 2 in the SR ty transient (in that case the DCP has to be re-calibrated).

- The unlocks were due to INJ fast unlocks (Piernicola will make an entry).