Virgo Logbook

Detector Operation (Operations Report)

zaza - 18:25 Tuesday 10 February 2026 (68648)

Operator Report - Daily shift

7:00 UTC at the beginning of the shift the ITF was found in DOWN UPGRADING with LOCKED ARMS. SDB2 angular and position loops and SWEB position loop were open, I closed them.
7:00 UTC ITF set to MAINTENANCE:

TCS chillers refill (Menzione)
Cleaning of the central buildind and FCIM/FCEM (external firm)
Nitrogen refill and vacuum maintenance (Vac & Mech group)
Telescreel Left machine changed due to malfunctioning (Di Biase)
Disconnection of accelerometer on SAS supply duct of NE, accelerometer and old sensors cabling on vac pipe removal in NE (#68650 Fiori, Lunghini, Quemener, Tringali)
TCS Thermal Cameras acquisitions, TCS CO2 Power Checks (operator)
WI timing adjustment (Boschi)
MCH Tango server shut off (#68649 Gkaitatzis, Carbognani, Boschi)
Restart NNF NNN and NSN after security stop (#68651 Van Hove)
Icewm config updated to support both CL7 and AL9 graphical environment (#68653 Carbognani, Seder)

	CH (W)	OUTER (W)	INNER (W)
WI	0.318	0.02	1.27
NI	0.582	0.09	0.582

ITF recovery:

8:00 UTC opening of SR BS and CRYO DET valves (Pasqualetti)
11:00 UTC SR optical lever checks (Ruggi)
11:30 UTC SR GUARD closing (Ruggi)
12:00 UTC ITF in PREPARE SCIENCE
The realignment was successful and the lock acquisition went up to CARM_NULL_1F smoothly, though we noticed values of B1p aroun 0.1 mA. We also noticed that NE_RH was off and the process was stuck, it was quickly fixed by Nardecchia from remote (#68655). ITF had being kept in LOCKED_ARMS waiting for NE_RH thermal gradient.
16:22 UTC ITF in CARM_NULL_1F with B1p_DC value down to 0.01 mA
17:30 UTC at the end of the shift I left the ITF in LN2

Images attached to this report

68648_1770744313_Screenshot 2026-02-10 at 18-23-37 DMS Event Monitor.png

68648_1770744313_Screenshot 2026-02-10 at 18-23-09 Plots for logbook report.png

Comments to this report:

mwas - 19:10 Tuesday 10 February 2026 (68657)

To recover LN2 there was not much to do on the DET side.

The SDB1 control with B5 work without any changes, it is likely that in single bounce the power is now too low on B5, and the threshold to enable the drift control in single bounce in the SDB1_LC process will need to be lowered so that it works in single bounce (in DRMI lock the power is orders of magnitude above the threshold in any case.)

The OMC temperature for locking on the carrier fundamental mode increased by ~60mK due to the change in master laser temperature set point. I have added step to the automatic ramp by hand, and then the automation saved that value in the Metatron ini file as the OMC lock was successful.

The OMC was quite misaligned during DC READOUT, once in LN2 the drift control realigned the bench by ~10urad, mostly in TY. I have adjusted the SDB1 B5 quadrant offset to 450um in H to get closer to the position that the drift control brings the bench to in LN2. This starts to be quite close to the edge of the quadrant, as now a larger fraction of the B5 beam is clipped by the diaphragm.

B1 PD3 has quite a large offset of -0.6uW. I have updated the offset in the SDB2 dbox bench process, but I haven't reloaded it as the interferometer continued the lock to LN2 despite the offset. To be done at the next unlock during normal working hours.

I have started the EDB OMC continous scan with the same parameters as in January. I expect the HOM will be shifted in temperature by ~60mK due to the ML temperature change, so the analysis will need to be adjusted. The EDB OMC alignment is quite bad, with 0.3mW instead of 0.6mW of 56MHz sideband TEM00 mode, and the order 1 mode of the 56MHz sideband has half the power of the TEM00.

bersanetti - 19:22 Tuesday 10 February 2026 (68658)

From the ISC point of view basically nothing was done. The only change I made is the demodulation phase for DIFFp_TY, which I lowered by 0.2 rad: it reduced a bit the signal in _Q and it was in the direction of making it equal to the TX one, so I made the change resident.

For tomorrow, after the complete thermalization: check the DARM gain for DC readout, as the UGF was quite low (55 Hz), compensated by the servo in time.

ITF left in LOW_NOISE_2 with the autorelock failsafe engaged with the same target.

mwas - 9:29 Wednesday 11 February 2026 (68660)

This morning around 6:00 UTC I have reload the SDB2 dbox configuration to change the B1 PD3 offset, which is now close to zero. I have also undone the changes in SDB1 B5 QD2 offsets done last night, as there were many unlocks during at the end of CARM NULL 1F during the night, and at the end of the CARM NULL 1F SDB1 switches to high bandwidth control which kicks the bench and may be moving the beam outside of the quadrant.

mwas, gouaty - 15:06 Wednesday 11 February 2026 (68665)

Today around 12h30 utc the DET_MAIN node could not reach the SHUTTER_CLOSED state due to a too large positive offset on B1_PD3 (about 0.14 uW). We reduced the value of the offset to bring the B1_PD3 signal close to 0, which solved the problem encountered by DET_MAIN. It is likely that this offset is still going to evolve in the next hours and that we will have to perform again this type of correction.

SDB2_dbox_bench configuration reloaded at 12h50 utc.