Reports of 61704
Virgo Runs (O4c)
menzione - 6:55 Sunday 10 August 2025 (67467) Print this report
Operator Report - Night shift

ITF found locked at LN3 in SCIENCE mode. It remained locked for the whole shift.

No DMS Events monitor to report

Guard tour (UTC):
21:00 - 21:40
00:00 - 00:40
02:10 - 02:50

Images attached to this report
Virgo Runs (O4c)
Sposito - 22:51 Saturday 09 August 2025 (67466) Print this report
Operator Report - Afternoon shift

Today, I found ITF in SCIENCE. 15:00 UTC ITF unlocked, 15:50 UTC ITF back in SCIENCE at the first attempt with Autorelock. 19:30 UTC CALIBRATIONS started.  

19:30-19:49 CALIBRATED_DF_DAILY.

19:59-20:19 ISC injections (inject_lsc.py) 

Guard Tours (UTC):

  • 13:20-14:00
  • 16:30-17:10
  • 18:10-18:40
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Virgo Runs (O4c)
amagazzu - 14:58 Saturday 09 August 2025 (67465) Print this report
Operator Report - Morning shift

ITF found in LOW_NOISE_3 and in Science Mode. It kept the lock for the whole shift.
ITF left locked.

Guard Tour (UTC)
5:00 - 5:45
7:40 - 8:20
10:40 - 11:20 

Images attached to this report
Virgo Runs (O4c)
berni - 6:55 Saturday 09 August 2025 (67464) Print this report
Operator Report - Night shift

ITF found in Science mode.

It unlocked at 00:27 UTC; after a manual prealignment of SR (strongly misaligned) the ITF reached LN3 at the first attempt and Science mode was set at 1:28 UTC.

 

Guard tours (time in UTC)

21:30-22:10; 23:20-0:00; 1:00-1:40; 3:00-3:02.

Images attached to this report
Virgo Runs (O4c)
menzione - 22:50 Friday 08 August 2025 (67463) Print this report
Operator Report - Afternoon shift

ITF found stable locked at LN3 in SCIENCE mode.
It remained locked for the whole shift.

Guard tour (UTC):
18:00 - 18:40

Images attached to this report
Virgo Runs (O4c)
Sposito - 14:50 Friday 08 August 2025 (67461) Print this report
Operator Report - Morning shift

ITF found in LOW_NOISE_3 and in Science Mode. It kept the lock for the whole shift.

Images attached to this report
AdV-SGD (FDS commissioning)
delauren - 9:14 Friday 08 August 2025 (67462) Print this report
Comment to SQZ source recovery attempt (67460)
Virgo Runs (O4c)
berni - 6:55 Friday 08 August 2025 (67459) Print this report
Operator Report - Night shift

ITF in Science mode for all the shift.

No DMS alerts during the shift.

 

Guard tours (time inTC)

21:00-21:40; 23:40-0:20; 1:40-2:20; 3:40-4:20

Images attached to this report
AdV-SGD (FDS commissioning)
zendri, De Laurentis, Lunghini, vahlbruch - 0:16 Friday 08 August 2025 (67460) Print this report
SQZ source recovery attempt

Today we worked on the recovery of the FIS source after the Virgos's main laser frequency change.

We have been focusing especially on finding the origin of the glitches that appeared in the green line (see figure PLL_ON).  To check if they are related to the new PLL setup we first turned off both the PLL loops (MAIN and CC), figure PLL_OFF.  Then with both the PLLs OFF  we moved the temperature of the main laser by -0.51 Celsius , figure PLL_OFF_LowerLasTemp.  These operations do not appear to have changed the glitch rate.  We then also lowered the temperature of the laser CC obtaining a similar result.

We also turned on/off the lasers noise eater,  we reduced the SHG threshold of about 10% and  and we did an inspection of DetLab.  Even in this case the actions were not decisive.   Further tests will therefore have to be done to understand the origin of these spikes.

Another problem we encountered is that the MAIN and CC beat notes, either with  the CC loop open or closed, have a comb structure that wasn't present during the last shift (# 67444). Also in this case further test are required.

 

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Comments to this report:
delauren - 9:14 Friday 08 August 2025 (67462) Print this report
Virgo Runs (O4c)
menzione - 22:54 Thursday 07 August 2025 (67457) Print this report
Operator Report - Afternoon shift

ITF found locked at LN3 in SCIENCE mode.
The BNS Range is fluctuating since this night in a visibly abnormal way. TBC.
At 15:00 UTC I set COMMISSIONING mode and the planned SQZ activity started with deLaurentis in Det Lab. Activity concluded at 20:50 UTC. SCIENCE mode set.
The fluctuation of BNS range is now disappeared. (TBC).

Guard tour (UTC):
18:00 - 18:40

AdV-ISC (Commissioning up to first full interferometer lock)
boldrini, zaza - 17:36 Thursday 07 August 2025 (67453) Print this report
Updated DMS thresholds for B1p_DC

We updated the DMS threshold for B1p_DC to account for the darker fringe of the past few weeks.

Considering a mean value of 0.0084 mW for B1p, the new thresholds at LN3 are:

  • yellow alert: 0.0076 < B1p_DC < 0.0092 (+-10%)
  • red alert: 0.0067 < B1p_DC < 0.0101 (+-20%)

LockMoni has been successfully stopped and started, with the ITF in Adjusting. We are now back in science mode.

Environmental Monitoring (Environmental Monitoring)
Paoletti, Fiori, Tringali, Pierini - 15:59 Thursday 07 August 2025 (67458) Print this report
Periodic seismic noise in CEB

We recently observed a periodic seismic noise in the CEB area affecting nearly all F0 suspension accelerometers.

Although this noise is effectively filtered by the SA chain and seems not visible in Hrec, its roughly three-hour cycle and characteristic double-pulse structure (two strikes separated by about 12 minutes, with minor timing variations) make it worth investigating.

Initial mapping with Newtonian sensors pointed to the northeast sector of CEB, and subsequent analysis narrowed the source region to the FCIM and FCEM zones.

Remarkably, each cycle unfolds as four pulses: an initial event in FCIM (or broadly the CEB area), a second in FCEM about 30 seconds later, then after roughly 12 minutes a third pulse again in FCEM, and finally a fourth back in FCIM/CEB about 30 seconds afterward. After three hours, the cycle repeats itself.

The implied propagation speed of ~10 m/s rules out a traveling‐wave origin.

Preliminary checks show that neither the (unlinked) HVAC units in FCIB and FCEB (per Davide Soldani, personal communication) nor the air compressor 150 m from CEB (which is under continuous monitoring) correlate with this noise, leaving the true source still unidentified.

It might be useful to place some seismic sensors near the HVAC units in FCIB and FCEB to shed light on this problem 

Images attached to this report
Virgo Runs (O4c)
zaza - 14:57 Thursday 07 August 2025 (67451) Print this report
Operator Report - Morning shift

ITF found in SCIENCE

08:37 UTC ITF set in ADJUSTING - see entry

08:39 UTC ITF set in SCIENCE

13:00 UTC ITF left in SCIENCE

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AdV-TCS (Point Absorbers Mitigation)
mwas - 14:20 Thursday 07 August 2025 (67456) Print this report
Comment to IPATSiA: measurements in LN2 (67367)

These are the best noise budget I could achieve for the data of July 24 during the latest IPATSiA test. In each case using the last 10 minutes of data of a given state of IPATSiA, in order to avoid the initial few minute transient from turing the power of IPATSiA on or off. The best shape to fit all the data had a slope of 1/f^0.55.

Figure 1 shows the noise budget for the first position (with 40mW of power)

Figure 2 shows the noise budget for the second position.

In both cases the plotted mystery noise level is the same, and it is 10% higher than in the case of LN2 data with IPATSiA off.

Figure 3 shows the noise budget for IPATSiA that was taken in between the two times shown in figure 1 and 2 

Figure 4 shows the noise budget for one hour after the IPATSiA test, with the interferometer back in LN3. Where the mystery noise is a factor 1.7 lower in terms of mW/rtHz, as expected from the change in HOM signal recycling gain.

Images attached to this comment
Environmental Monitoring (Environmental Monitoring)
Paoletti, Fiori, Tringali - 12:30 Thursday 07 August 2025 (67455) Print this report
Comment to WEB acoustic injection commissioning break (66483)

For this injection (April 1), we injected filtered white noise (8–1000 Hz) into the WEB using two loudspeakers. Although the loudspeakers were unable to generate acoustic waves below approximately 50 Hz, Hrec nonetheless exhibited an increase in noise between roughly 10 and 50 Hz.

Simultaneously, the "in-loop" optical lever signal (Sc_WE_MAR_PSDT2_Y2) was heavily disturbed by the acoustic injection. This disturbance may explain the rise in low-frequency noise observed in Hrec (to be confirmed).

On July 21, we repeated the same injection using only one loudspeaker, halving the acoustic power. Under these conditions, Hrec showed a much smaller response (colour scale are unchanged).

We plan to upgrade the acoustic injection system next months. The enhanced setup will allow us to vary sound levels across the terminal buildings to determine whether the Hrec low-frequency noise persists at higher amplitudes and whether its behavior is linear or shows a threshold effect. It remains to understand and correct the behaviour of this optical lever system, to check if it is really the source of the Hrec noise.

A question raised during a discussion with Paolo Ruggi was whether the coupling observed on the optical lever originates from the magnetic field.
This scenario appears unlikely: the standard Metronix magnetometers (middle row in the attached spectrogram) do record a field increase, but they sit immediately adjacent to the loudspeaker cables (see first photo).
By contrast, the triaxial fluxgate (bottom row) located near the tower—and thus close to the optical lever—shows no measurable change in magnetic field.

Images attached to this comment
AdV-ISC (LSC Noise Budget)
boldrini - 10:06 Thursday 07 August 2025 (67452) Print this report
SSFS noise budget

Here's the noise budget for the SSFS injection of August 4th.

Images attached to this report
Virgo Runs (O4c)
tomelleri - 6:56 Thursday 07 August 2025 (67450) Print this report
Operator Report - Night shift

ITF remained locked in LOW_NOISE_3 for the whole shift with SCIENCE mode (Autoscience ON); BNS Range ~55 Mpc. No relevant DMS events.

Guard tour (UTC)
21:48 -> 22:20
23:33 -> 00:11
01:33 -> 02:13
03:43 -> 04:20

Images attached to this report
Virgo Runs (O4c)
berni - 22:57 Wednesday 06 August 2025 (67449) Print this report
Operator Report - Afternoon shift

ITF in Science mode for all the shift.

 

Guard tours (time in UTC)

18:00-18:40

Images attached to this report
Virgo Runs (O4c)
menzione - 14:50 Wednesday 06 August 2025 (67445) Print this report
Operator Report - Morning shift

ITF found locked at LN3 in SCIENCE mode.
At 11:29 UTC ITF unlocked due to an earthquake occurred in Russia (pict1).
Aurorelocked at first attempt. Auto SCIENCE mode.

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AdV-TCS (CO2 laser projector)
mwas - 9:11 Wednesday 06 August 2025 (67446) Print this report
Comment to Attempt to stabilize WI CH Power using PyTCS Process (67436)

Looking at the figure the error signal used for the PyTCS loop, TCS_WI_CO2_POWER_CH_PSTAB, is unaffected by the waveplate. On the other hand the total power of the DAS+CH correction, TCS_WI_CO2_POWER_CH_PICKOFF, sees the waveplate rotation. So either the actuator is wrong and it is the DAS power that was changed, which seems to me very unlikely as the interferometer in steady state looks unchanged. Or it is the waveplate that is located after the TCS_WI_CO2_POWER_CH_PSTAB power meter pickoff, which means that the error signal for PyTCS need to be changed to look at a signal after the actuator, for example change the error signal to TCS_WI_CO2_POWER_CH_PICKOFF.

Virgo Runs (O4c)
tomelleri - 6:55 Wednesday 06 August 2025 (67443) Print this report
Operator Report - Night shift

ITF remained locked in LOW_NOISE_3 for the whole shift with SCIENCE mode (Autoscience ON); BNS Range ~53-55 Mpc.

Guard tour (UTC)
21:36 -> 22:13
23:32 -> 00:11
01:37 -> 02:12
03:42 -> 04:19

Sub-system reports

DET
2:30UTC - SDB2_B1p_DC power returned below its red threshold on DMS (fig.1) after initial transient starting around yesterday's activity on SR at 11:40UTC (entry #67442)

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Injection system (General activities)
zendri, toffano - 23:40 Tuesday 05 August 2025 (67444) Print this report
Comment to ML crystal temperature change - mode hop check (67348)

Today, with the help of a spectrum analyzer, we restore the squeezer MAIN  and CC  PLLs. The previous entry's (67359) setting probably   referred to a spurious beat signal which was very faint (about  -25 dBm).

With the new settings:

MAIN  PLL:  31594

CC PLL:       31437

the PLLs lock are stable in time. While we had no  time to work on the SC PLL, which however is not used in this period.

We also used part of the shift time to calibrate the laser temperature versus the DAQ bit count and, in the case of the main PLL, also the frequency shift to the bit count. The results are shown in the attached figures.

With these calibrations we were able to estimate that to restore the PLLs we had to increase the temperature of the lasers respectively by

MAIN PLL Temp increment 1.49 Kelvin

CC PLL Temp increent 1.43 Kelvin

which is compatible with the increase in temperature of the main laser reported in #67348

Non-image files attached to this comment
Virgo Runs (O4c)
berni - 22:56 Tuesday 05 August 2025 (67441) Print this report
Operator Report - Afternoon shift

ITF found in Science mode.

At 14:05 UTC ITF in Commissioning mode for the planned activity of Squeezing; activity concluded at 18:35 UTC.

 

Guard tours (time in UTC)

18:00-18:40

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AdV-COM (AdV commissioning (1st part) )
mwas - 21:37 Tuesday 05 August 2025 (67442) Print this report
Comment to Restoring double cavity pole frequency and continued SR TX offset (67424)

Figure 1. Today during the relock after the maintenance I have added in the ITF_LOCK automation that an SR TX offset is added at the same time as the SR TY offset when acquiring LN3. This has worked successufully, and added the offset that of 0.015 that has been working well for the past few days.

Figure 2. The BNS range this afternoon has not been as good as before the maintenance, it may be due to some drift in alignment that occurred during the maintenance, SR TX changed by ~7urad, and the drift control is slowly recovering that with the SR TX error signal not actually managing to arrive back to zero.

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Environmental Monitoring (Environmental Monitoring)
Tringali, Paoletti, Loche, Fiori - 16:25 Tuesday 05 August 2025 (67440) Print this report
acoustic isolation of doors 34, CEB L2
This morning we performed a set of loudspeakers injections with the purpose to measure the acoustic isolation 
of the two (equal) fire-protection doors located in CEB, L2 at the entrance of the Clean room AHU room (see picture). 
The two doors are parallel approx. 2 m apart, and are structurally the same. 
Two subwoofers were positioned in the AHU room, as well as one microphone (GRAS 46AZ) named "IN", while the other 
one (GRAS 46AZ) named "OUT" was positioned on the other side of both doors (see picture) or in between. 
The used generator sent uncorrelated white noise to each speaker.

The log file with times and actions is attached. 

The attached pictures compare the two mics spectra in different conditions:

(a further analysis will follow to convert the spectra in acoustic dB versus octave bin)

During INJECTION

  • Huddle test (both mics closeby)
  • both doors open
  • only door IN closed ("IN" is the door closer to the AHU room)
  • only door OUT closed ("OUT" is the other door) 
  • both doors closed
  • both door closed and "OUT" mic in between the two doors

No injection, only QUIET ambient noise

  • both doors open
  • only door IN closed
  • both doors closed
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Non-image files attached to this report
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