Yesterday a noise injection on SR MAR angular dofs has been performed, in order to estimate the noise projection of local controls (optical levers) on Hrec. Also a noise injection on SR MIR Z has been performed, in order to estimate the projection of DAC noise on Hrec.

gpsSRTX=1441034478;durration=600;
gpsSRTY=1441035698;duration=500;
gpsSRZ=1441036758;duration=140;

Atteched figures show the transfer functions and the projections of clean data. Concerning TY, there was no coherence between the injected noise and Hrec, so the TF can be used only as an upper limit. Concerning Z, fig 6 shows also a projection of SR locking correction, based on the present injection. It could be an over-estimation of the actual SRCL noise projection: it is not clear to me if in normal condition some subtraction of locking sensing noise performed by Hrec can be effective in reducing this coupling.

For completeness, a photo of the location of the electrical box to switch on the light in the towers. It is on the ground floor of the central hall.

Figure 1. Looking at the DMS there seem to be a light that was turned on in the central building during the last maintenance, and that has been left on. It would be good to turn it off at the next occasion. Either the next unlock, or in the worst case scenario at the maintenance of next week.

21:00 UTC ITF found in SCIENCE
22:53 UTC unlock, ALS_WARM node stuck, restarted
23:58 UTC ITF in SCIENCE

Guard Tours (UTC)
21:04 - 21:40
23:08 - 23:46
1:09 - 1:47
3:11 - 5:11

ITF found locked in LOW_NOISE_3 with SCIENCE mode (Autoscience ON); BNS Range ~53 Mpc. Unlocked at 13:25UTC due to nearby earthquake (ID: 139556451) that sent EIB_SBE loop ringing (DMS plot in fig.1). 13:32-14:09UTC taking advantage of today's unlock ITF parked in LOCKED_ARMS_IR in PREPARE_SCIENCE to close SQZ shutter on SDB1 (entry #67637). ITF relocked in LN3 by Bersanetti at 15:01UTC. COMMISSIONING moode set at 14:52UTC for INFN Napoli intervention on tiltmeter at NEB (entry #67636), low frequency noise analysis and scattered light calibration activity planned for this evening. LSC injections not performed due to script malfunction, expert notified. Back to SCIENCE mode with Autoscience engaged at 18:52UTC. ITF left locked.

Guard tour (UTC)
17:59 -> 18:34

Calibration
18:23-18:45UTC CALIBRATED_DF_SCATTEREDLIGHT injection performed from CALI node.

DET
14:06UTC - SQZ shutter on SDB1 closed (via FI Shutter Relative Movement process on VPM) that had been left open since 2025-09-02 at 10:31UTC after SQZ recovery.
Boldrini, Degallaix and I entered CEB between 13:59 and 14:09UTC to turn lights on in DET tower (fig.2) to allow DET on-call (Gouaty) to confirm that the shutter closed correctly.

Other
Two large planes flew over the site at low altitude around 19:42UTC in clear violation of the no-fly zone (cfr. entry #67634)

This afternoon I was contacted by the control room to close the SDB1 Faraday shutter. I checked the position of the shutter on the camera ipcam43 which is looking at the north side of SDB1. Since I was not sure about the image I was looking at I asked the control room to switch on the light in the detection tower.

After that I performed about -60000 step on the FI shutter with the SDB1_Rot process in order to bring back the shutter in the closed position. The shutter was moved between 13h58 and 14h06 utc.

While the ITF was unlocked, we went to the North Terminal Building. We arrived at 17:00 LT and we left at 17:11 LT.

We decided to switch off the power supply of the tiltmeter actuators, hoping to see improvements in its signals.

As has happened many times in the past, this morning we had planes flying over Virgo, violating the no-fly zone. They came from the small airport located on Via dello Zannone. The signal is clearly visible on many microphones, seismometers, and accelerometers in the Central Building. To the naked eye, there appears to be no effect in HREC, but I'll leave that to the experts with their powerful analysis tools.

ITF found in LOW_NOISE_3 and in Science Mode. It unlocked at 2:04 UTC, back in Science Mode from 2:59 UTC.
ITF left locked.

13:00 UTC ITF found in SCIENCE
15:45 UTC start of COMMISSIONING: 15:50- ISC injection (inject_SSFS.py)
16:17 UTC start of CALIBRATION: 16:21-16:40   CALIBRATED_DF_SENSITIVITY, 16:41-17:00    CALIBRATED_DF_PCAL
17:02 UTC ITF in SCIENCE
18:10, 19:15, 20:35 UTC data loss

Guard Tours (UTC)
17:57 - 18:37

ITF remained locked in LOW_NOISE_3 for the whole shift with SCIENCE mode (Autoscience ON); BNS Range ~53 Mpc.

The SC PLL has also been restored after changing the Virgo main laser frequency ( see #67348 and #67444)

In order to close the PLL loop the SC laser peltier has been moved from 31875 to 38040

The PLL offset measured by the monitor line was found to be 1.260 GHz (monitor peak amplitude -26.1 dBm)

We also found the SC laser driver turned on but in the "OFF" configuration while we are not aware of anyone having done this by hand. This has happened many times lately which is a symptom of a malfunction in the laser driver electronics.

ITF found in LOCKING_ARMS_BEAT_DRMI_1F and Bad_Weather Mode. After a series of attempts the ITF was back in LOW_NOISE_3 from 14:51 UTC.
From 15:00 UTC to 17:50 UTC Vardaro and Zendri worked on the the Squeezing recovery (see report  #67625).
From 17:55 UTC to 18:50 UTC, with the support of Tringali, I performed the ENV noise Injections.
ITF back in Science Mode from 18:56 UTC. During the past few hours, the Hrec_Range_BNS value has occasionally fall below 45 (see attached plot).
ITF left locked.

Guard Tour (UTC)
17:58 - 18:33 
20:32 - 21:08 

In the afternoon shift we recovered the alignment between SQZ and ITF

At 15:30 UTC we conclude to open the SQB1 shutter and to rotate the SQB1 HWP2 in order to send SQZ light toward ITF

At 15:32 UTC we open the fast shutter to check the level of B1 4MHz mag

Then we open the SQZ Fast Shutter and with the automation we started the realignment

We found that SQB1_M1_X was saturating at +9V. Thus we increased by a factor 5 the amplitude of dither lines, then we discharged SQB1_M1_X acting on the picomotors SQB1_M32_H and SQB1_M33_H in positive direction with iterations of 700 steps

At the end of the process the SQB1_M1_X was at 5.2V

Then we checked the clipping with SQB1_RetroRef but was ok. So finally we moved SQB1_LC_X and we passed from -3300 um to -3700 um and the magnitude increased at its maximum

We noticed that passing from SQZ to ASQZ the effect on the range was negligible thus we decided to run a phase scan.

Start GPS 1440867965, end GPS: 1440869748

The squeezer is completely recovered but its effect on the ITF is negligible (fig 1).We left the interferometer with SQB1 shutter closed and SDB1 shutter open in order to not unlock

I have also removed files from the directory MECHANICS, containing configuration files of mechanical simulations. I have understood that virgoData is not the right place to do this kind of activity, so I will move everything somewhere else as soon as possible.

Triggered by the S.Cortese's mail related to the load of the  /virgodata disk area,  the cleaning of the  VPM and Cm sub-directories located in this disk has been performed:

• For each VPM  server, there is a sub-directory called /virgoData/{VPM-name}/backup where all the configuration files are backed up
• for each  Cm domain , there is a sub-directory called /virgoData/Cm/{CM-domain-name}/ where the logfiles related to the Cm name server are stored
• for all these directories only the  last 3 years' files have been kept .

As consequence the use of the /virgoData changed

• from at 09h22m-UTC
  • Filesystem         1K-blocks     Used Available Use% Mounted on
    olhomes:/virgoData  51475456 37114880  11739136  76% /virgoData
  • 5606976KB    /virgoData/Cm
  • 4815836KB    /virgoData/VirgoOnline
  • 2672368KB    /virgoData/LowLatencyAnalysis
     
• to at 15h37m-UTC
  • Filesystem         1K-blocks     Used Available Use% Mounted on
    olhomes:/virgoData  51475456 27495424  21358592  57% /virgoData
  • 2615644KB    /virgoData/LowLatencyAnalysis
  • 1520556KB    /virgoData/Cm
  • 1271728KB    /virgoData/VirgoOnline

This morning, we went to the North Terminal Building in order to better understand the problems we had with the GRAS 47AC and the GRAS 46AZ microphones last Tuesday.

Since those mics used to work at CEB, but had problems at NEB, we tried to go back up to the cause. We entered NEB at 9:35 LT; below is a list of our attempts:

1. at 9:41 LT we substituted the BNC to LEMO adaptor that was on the ADC;
2. at 9:43 LT we substituted the GRAS 46AZ, present at NEB since last Tuesday, channel “ENV_NEB_MIC_GRAS_HF”, with the infrasound GRAS 47AC, adequately changing the calibration as well. Despite the GRAS 47AC being an infrasound microphone, its ASD response wasn’t as high as it was when we installed it at CEB;
3. at 10:06 LT we changed the BNC cable connecting the PCB 482C05 with the ADC;
4. at 10:22 LT we tried to use the GRAS 12AL instead of the PCB;
5. at 10:30 LT we changed the ADC channel by temporary swapping the “north” B&K 4193 (channel “ENV_NEB_MIC_4193_N”) with our GRAS; we swapped them back at 10:36 LT;
6. finally, at 10:42 LT we changed the other BNC connecting the PCB with the mic.

Unfortunately, none of these attempts have been successful in identifying the problem. Our future aim will be to go back to the CEB and repeat the operations we did last Tuesday. Before that, we decided to keep the standard GRAS 46AZ at NEB.

Apart from this, we installed windproof balls on the GRAS 46AC (“ENV_NEB_MIC_GRAS_HF”) and on the 4193 (“ENV_NEB_MIC”), as showed in Figure 1, and we changed the position of the two B&K 4193 installed last Tuesday, to see if anything changes. They initially faced the tiltmeter chamber, whereas now (starting from 11:45 LT) they’re facing outwards, as one can see in Figure 2.

Today we recovered the control of SQB2_SBE, FCIM_SBE and FCEM_SBE

Then we re aligned the FCIM reflection using ipcam61 and we found the peaks on FCEM_GR_PD_DC by moving FCEM mirror

Once we had peaks in transmission higher than 2V we reacquired the lock and the alignment using the automation.

We found the maximum of green tranmitted equal to 3.2V (lower than the 4V we had in april) so we lowered the DC_max in the automation from 4V to 3V

5:00 UTC ITF found in CARM_NULL_1F - BAD WEATHER
5:32 UTC ITF in SCIENCE
6:00 UTC start of MAINTENANCE
10:15 UTC PREPARE SCIENCE - troubles locking due to strong winds
12:25 UTC Strong wind gusts, difficulties locking the DRMI, ITF set to BAD WEATHER

Tasks performed:
6:15 UTC Squeezing Recovery (Henning, Vardaro, Zendri)
6:30 UTC Periodic Nitrogen Tank Refill (Vacuum Team)
6:40 UTC Fbm checks, FbmFFE restart (Masserot)
6:45 UTC CEB, FCIM, FCEM cleaning (Ciardelli, external personnel)
7:00 UTC TCS Chiller check and refill (Ciardelli)
8:28 UTC PR OpLev Survey (Boldrini, De Rossi, Degallaix)
8:30 UTC NEB microphone change (DeRosa)
8:30 UTC Loud speaker changes in all buildings (Fiori, Tringali)
9:00 UTC IB, MC, NI IP centering (Boschi)
9:45 UTC TCS CO2_CH Power adjustments (Nardecchia)

Tasks performed by the operator:
6:00 UTC OMC Scan
7:05 UTC WI CO2 CH Adjustment
7:20 UTC TCS Thermal Camera Pictures Acquisition
8:21 UTC TCS Powers Check

This morning during maintenance we replaced the loudspeaker of NEB with one of the new loudspeakers (Proel, mod. DIVA 15A, 1000W processed active speakers). The speaker is placed in the NW corner of the hall (see picture). With the actual metatron setting (Volts to DAC) and the volume knob set at max the sound level in the hall is very close to the value achieved with the old speaker. The speaker is connected to the wall plug and left on, as needed to by the temporary fixing to automatized ENV injection done by Maria. In Figure 2: the orange curve is one injection with the old speaker, the blue curve is what achieved with the new speaker, with the present settings.

Troubleshooting and actions postoned to the next access:

• the new loudspeaker emits a sound at 50Hz and harmonics, likely due to a noise pick-up. Federico tested various configurations to eliminate possible pick-ups from the ground. But this needs further investigation.
• the final setup foresees two such speakers, the second one in the NE corner. We tested this configuration, but when connecting the second speaker the 50Hz sound noise became much louder. We decide to leave the second speaker off, until a fixing is found.
• the DAC injection level sent to the loudspeaker shall be increased a bit, to eventually double the spectral level of noise generated inside the hall, this shall be done at the level of the metatron code. 

In order to continue in the afternoon shift with the recovery between SQZ and ITF we open the SDB1 FI shutter at 10:32 UTC. We did +36000 steps

Since there were several yellow flags related to the IP centering and the vertical direction of suspensions we have performed the following operations:

- Horizontal centering of the IP for: MC, IB, NI

- Vertical centering of MC F4

At the end of the intervention, all suspensions were back to normal operations.

Start of the activity: 11:05 local time

End of the activity: 12:07 local time

After the work of yesterday we recovered a very small PumpPhase error signal. This morning starting from 8:00 UTC Hennong worked to recover the amplitude of the PumpPhase error signal. So he acted on the OPA parametric gain by tuning the OPA crystal temperature.

He manage to lock the squeezer around 7:35 UTC, but the parametric gain is lower than usual. The change of the frequency of the laser affected a lot the optimal temperature of the OPA nob-linear crystal, before the set point was -3.3 now is -3.02.

From 8:05 UTC we started a small campaign of measurement with the HD detector in order to quantify the decreased parametric gain.

From 8:10:04 we took 2 mins of shot noise with the HD detector. The average of the EQB1_HD_DIFF_AUDIO_RMS_1_3kHz_dB. Is slightly lower than 0dB (-0.05dB) so the channel should be renormalized. The spectrum of the HD DIFF Audio channel in shot noise is the one expected.

At 8:18:17 UTC we open the EQB1 fast shutter and we start to tune the SQB1_HWP2. We rotated the HWP by 21000 steps.

8:36:54 UTC an open loop CC measurement was done to measure the parametric gain that is equal to 4.76/1.78=2.67, i.e. 8.5 dB of SQZ generated.

8:52 to 9:02 UTC we aligned the HD detector. After the alignment we had a parametric gain of 6.3/2.35=2.68 i.e. 8.5 dB sqz generated.

We took spectra of SQZ and ASQZ with HD detector

- ASQZ 9.12:27 UTC 7.85 dB 0.93 rad

- SQZ: 9:20 UTC 5.3 dB at 2.25rad

Comparing with this enty https://logbook.virgo-gw.eu/virgo/?r=57124 in sept 2022 with 8.5 db generated we measured 7.9 dB of ASQZ and 5.65 dB of SQZ.

After some tuning (alignment SQB1_HWP2 and Retro ref) we obtained the following vanlues

ASQZ: 8 dB at 0.85 rad 9:44 UTC 6.66mV 2 min

SQZ: 5.65 dB at 2.2 rad 2.56mV 9:54 UTC 2 min

So the squeezer is recovered and we left the SQB1 HWP rotated to send the sqz light toward HD detector.

In the afternoon we can continue to recover the alignment between SQZ and ITF