A line at approx 23Hz appeared on June 3rd in some environmental sensors inside the laser lab, specifically: microphones and seismic sensors. The noise is not seen by accelerometers on IB tower. It makes me think that the source could be inside the laser lab. The noise is up since then. Apparently the noise is not seen in Hrec, at least no coherence by Bruco. It could be interesting anyhow to identify the source. Any hint?

ITF found in Science (LN3), BNS Range ~52Mpc

• 05:42UTC, ITF unlocked (1st plot)
• 06:22UTC, back to Science
• 07:58 - 08:30 & 08:47 - 09:19 UTC, Adjusting mode to allow A. Pasqualetti and R. Macchia to perform an intervention on WI Cryotrap and restore proper operation
• At the end of the intervention, ITF unlocked
• ITF relocked at 11:17UTC after a manual unlocked due to no presents of trigger at LOCKING_ARMS_BEAT_DRMI_1F step altough the PR and SR realignments
• 12:33UTC, Adjusting mode to perform Etalon steps as planned

ITF left in Science

I'm in the process of tuning the gain of the down condition so the new gains are:

west down gain from 0.0167 to 8e-3; north down gain from 0.011 to 6e-3. The reload will be done soon

This morning we intervened in the CEB to restore the operation of the cryogenic circuit supplying the WI cryotrap that started malfuntioning during the past night (see also the operator entry). 
The electropneumatic actuator of the phase separator was found blocked and it was replaced.

The operation was carried out in two phases,  refer also to the operator logentry .

Some comments about the 9 unlocks events related to glitches on NE or WE

• Remarks:
  • The Sc_{N,W}E_MIR_LSC_CORR channels are the copy of the LSC_{N,W}E_CORR ones after extension from 10KHz to 40KHz and then filtered and decimated at 10KHz before being sent  to the DAQ
  • To superpose the Sc_{N,W}E_MIR_VOUT_XX channels some of them have been multipled by  -1,
  • The delay of 10 us related to the ISC_Tpro server,  the delay  of 16us related to the propagation time to the terminal building, and the latency 3us introducing by the 3  MxDx_v1  have been added to its elasped_time channel (ISC_Tpro_elapsed_time + 29us), which means that this time  the packet s should available for the Sc_{N,W}E DSPs running at 40KHz, meaning for 10KHz cycle  0us, 25us, 50us or 75us
  • the delay between the LSC_{N,W}_CORR and its feedback by the DSPs Sc_{N,W}E_MIR_LSC_Corr is 454us
• 20250613-11h08m02s-UTC :  plot, zoom - WE glitch - Max expected time for Tolm packets at NE and WE : 73.8us 
• 20250613-19h13m07s-UTC : plot, zoom - WE glitch -  Max expected time for Tolm packets at NE and WE : 73.8us 
• 20250613-21h07m32s-UTC : plot, zoom - WE glitch -  Max expected time for Tolm packets at NE and WE : 74us
• 20250614-01h43m09s-UTC : plot, zoom - NE glitch -  Max expected time for Tolm packets at NE and WE : 72us
• 20250614-18h27m31s-UTC : plot, zoom - WE glitch - Max expected time for Tolm packets at NE and WE : 73.9us
• 20250614-21h48m00s-UTC ; plot, zoom - WE glitch - Max expected time for Tolm packets at NE and WE : 73.8us
• 20250615-00h26m23s-UTC : plot, zoom - NE glitch - Max expected time for Tolm packets at NE and WE: 72.8us
• 20250615-15h34m44s-UTC : plot, zoom - NE glitch - Max expected time for Tolm packets at NE and WE: 72.8us
• 20250615-22h58m03s-UTC : plot, zoom - WE glitch - Max expected time for Tolm packets at NE and WE: 73.7us

Some observations :

• during this time period, 2,5 days,  there is3 events at NE  and 6 events at WE 
• for each event, on the Sc_ {N, W} E_MIR_LSC_CORR  channels only tiny distortions are observed while for the Sc_ {N, W} E_MIR_Z_CORR ones the distorsion is higher  and may sometine be huge.  Note that the channel is received by one single DSP board and then transmitted to others DSP boards to be sent to the DAQ and to be used for the control loops . How this discrepancy between the distortions can be explained ?
• the last plot shows the histogram of the ISC_Tpro_elapsed_time+29us for the  20250615-15h34m44s-UTC  NE glitch event and highlight the bin related to this event.

Following an indication by Bernardo (EIB and LB microphones and accelerometers "low response" since June 16th) we inspected EERoom and found the Nexus module that powers those sensors in off state. We ridentified the faulty piece being the AC/DC converter of the module. It is not the first time that this happens by the way. This componet was replaced and the Nexus and sensors put back in operation within the maintenance time. Figure 1.

During the operation we accidentally unplugged the CLIO-Pre01 module powering the EERoom's microphone (channel ENV_EER_MIC). Once replugged the microphone worked for about one hour and then went off. Surprisingly the microphone restarted working this morning at 5:00 UTC (7:00 LT).  We are not aware of any dedicated action. One suspect is some loose contact. To be checked at next maintenance. Figures 2 and 3.

ITF found in LOW_NOISE_3 and in Science Mode. It unlocked at 21:24 UTC, back in Science Mode 22:10 UTC.
ITF left locked.

VAC 
VAC_LN2WI..LT01_PS_LEVEL value decreased during the night (see attached plot). Experts informed of the issue.

Guard Tour (UTC)
23:01 - 23:44 
1:03 - 1:44
3:06 - 3:46

ITF found DOWN in BAD_WEATHER mode.
EDB OMC HOM noise measurement in LN2 (Was) skipped for another window next week
Relocked at LN2 at 18:09 UTC, COMMISSIONING mode set. SWEB&SDB1 scatter coupling LN2 (Gouaty) activity started. At 19:18 UTC the measuremnts needed LN3.

Activity concluded at 20:20 UTC. SCIENCE mode set. AUTOSCIENCE_ON.

SBE
SBE_SNEB_ACT_F0V_raw_50Hz out of DMS threshold (fig1).
Experts informed and fixed at 16:30 UTC.

Air Conditioning
(17-06-2025 16:30 - 17-06-2025 18:00) On site
Status: Ended
Description: I contacted ACS OnCall for a check of ACS in COB / Computing room

This evening we performed some sine injections on SDB1 and SWEB benches in order to measure the back-scattered light coupling transfer functions. We did these measurements both in Low Noise 2 and Low Noise 3 in order to check the impact of the SR alignment.

1/ Noise injections in Low Noise 2:

Reference data taken in Low Noise 2 from 18h11 utc to 18h15 utc.

1.1/ Noise injection on SDB1 (by acting on the suspension top stage F0):

We apply a sine function at 0.1 Hz, with an amplitude set to 0.2 in the damping interface, which corresponds to a bench motion of +/-5 um at ~18h17.

Amplitude increased to 0.4 at 18h19m30, bench motion of +/-10 um.

Amplitude increased to 0.7 at 18h21m40 utc, bench motion of +/-17 um. We start to see an effect on the sensitivity curve (see Fig.1). Glitch at 18h22m50. We collect data until 18h27 utc.

1.2/ Noise injection on SWEB (acting on SBE top stage):

We start injecting a sine function at 0.2 Hz, with amplitude set to 1 in the SBE config file at 18h39m56 utc: no clear effect on the bench position.

Amplitude increased to 50, at 18h42m40 utc, corresponding to bench motion of +/-6 um.

Amplitude increased to 100 at 18h44m50 utc, corresponding to bench motion of +/-12 um, still no clear effect on the sensitivity.

Amplitude increased to 150 at 18h49m39, corresponding to bench motion of +/-20 um. We can observe the noise coupling in the sensitivity curve (see Fig.2). Glitch at ~18h52. Injection stopped at 19h08 utc (we observed an intermediate glitch but did not write the time).

2/ Noise injections in Low Noise 3:

Reference data taken in Low Noise 3 from 19h21 to 19h26 utc (5 min).

2.1/ Noise injection on SDB1 (from F0 stage):

We apply a sine function at 0.1 Hz, with an amplitude set to 0.7 in the damping interface, which corresponds to a bench motion of +/-17 um at ~19h28m46 utc. Glitch at 19h32m30 utc. Taking data until 19h37 utc. See Fig.3

After stopping the SDB1 injection, we wait for the sensitivity curve to come back to normal noise level below 20 Hz. Then we collect some reference data from 19h45 utc (4 min).

2.2/ Noise injection on SWEB (from suspension top stage):

We inject a sine function at 0.2 Hz.

Start injection at 19h49m26 utc, with amplitude set to 50, corresponding to a bench motion of +/-6 um.

Amplitude increased to 100 at 19h51m29 utc, corresponding to +/-13 um. Collecting data until 19h57 utc. Fig.4

2.3/ Noise injection SDB2:

As a check, we performed another injection on the SDB2 bench with a frequency line at 0.1 Hz.

Start injection with amplitude set to 10 at 20h03m17 utc, corresponding to bench motion of +/-3 um.

Injection increased to 50 at 20h05m19 utc, corresponding to bench motion of +/-14 um.

Injection increased to 75 at 20h07m38 utc, corresponding to bench motion of +/-20 um. Stopped injection at 20h14m50 utc. See Fig.5

The following report has been submitted to the On-call interface.

On-call events -> Air Conditioning

Title: Issue on the computer room with the air conditioning system CDZ7 and HVAC 3000N

Author(s): andreazzoli

Details:

CDZ7--> Reset high pressure alarm
NE hvac --> Chiler 1 and chiller 2 status "OK" no alarm

* Note that any files attached to this report are available in the On-call interface.

This is a nice analysis, it would mean that the quality factor of EM01 has increased compared to the last measurement VIR-0407A-23. Back in 2023 the quality factor was measured to be ~100e3, and now it has increased to ~650e3, which is comparable to the measurement of that same mirror in 2020.

Note that most of the other measurements were done using the ring down of a kick of the mirror. I don't know if the result of the fit of the steady state width of the line can bias the result to be an under or an over estimate.

I performed a quantitative estimate of the quality factor variation using Lorentzian fitting. The model used is a sum of a power-law baseline and four Lorentzians, each convolved with an f^−2 response to account for interferometer response. The model is as follows around the frequencies of the drum modes:

Figure 5 (LaTeX equation)

where f_i is the frequency of the drum mode 3 for each test mass, and Q_i their quality factors. 

Figure 1 shows the PSDs of the V1:SDB2_B1_PD2_Audio channel around the frequency of drum mode 3 of the test masses, across three different periods, late March (with the original WE mirror), mid-May (with the replacement WE mirror), and early June (with the old NE mirror reinstalled at WE). Besides a slight drift in frequency, it's evident that the current WE mirror exhibits a lower quality factor, as discussed by Fiodor and Michal in the previous entries.

Fit Results Summary:

Baseline: A = 11.

Mass 1: A_1 = 19e3, Q_1 = 32e5, f_1 = 7798.708,

Mass 2: A_2 = 52e3, Q_2 = 93e5, f_2 = 7805.979,  

Mass 3: A_3 = 48e3, Q_3 = 16e5, f_3 = 7806.684,

Mass 4: A_4 = 75e3, Q_4 = 65e4, f_4 = 7814.724,

Note: A frequency drift is observed for some masses, likely due to temperature stabilization effects, e.g. in Fig. 2. This may have caused an underestimate of the corresponding Q_i. I attempted to reduce the data interval to minimize this drift, but the reduced resolution of the spectral estimate resulted in nearly identical fit outcomes accounting for uncertainty.

A similar fit repeated for mass 4 in the other period resulted in:

March 30: A_4 = 32e3, Q_4= 71e5, f_4 = 7814.531,

May 15: A_4 = 30e3, Q_4 = 715e4, f_4 = 7817.553.

This means that the quality factor for mass 4 (WE) is about one order of magnitude lower than before.

ITF found in LOW_NOISE_3 and SCIENCE mode (Autoscience ON).

ITF moved to SINGLE_BOUNCE_NI in Maintenance mode at 6:20 UTC for weekly maintenance.

ITF moved to LOCKED_ARMS_IR at 8:06 UTC for IMC working point check.

Lights in CEB checked by Nenci at 10:09 UTC.

After multiple unsuccesful attempts at lock acquisition ITF set to LOCKED_ARMS_IR in BAD_WEATHER mode at 10:34 UTC waiting for wind to subside.

Lock acquisition in progress.

DAQ
8:00 UTC White Rabbit node switched off by Cavalieri

EnvMoni
7:40 UTC Intervention in EEroom to fix EIB/LB microphone/accelerometers by Fiori, Garufi and Tringali.

ISYS
7:40 UTC Removal of thermal camera from WI viewport by Melo.

Other
08:10 UTC Newtonian Noise Cancellation sensors plugged back in by Tringali.

9:10 UTC experiment presentation in CB with camera crew by De Rossi, Casanueva.

TCS
7:30 UTC Spare chiller moved from TCS room by Ciardelli to CEB balcony, waiting for transport to WE for point absorber characterization.

12:28 NI Power adjustments in NI lasers by 2-3% by Nardecchia.

As consequence, there is no more reference clock provided  to the DBOX SN173, labelled as TIMING_DBOX_WR .

To avoid possible issues with Tolm packets sent by this one,

• at the SUSP_Fb level the data collection of all the TIMING_DBOX_WR Tolm packets have been disabled at 2025-06-17-09h44m29-UTC
• as well the readout of the TIMING_DBOX_WR Tolm packets by the SUSP_Tpro server . As consequence the TIMING_moni server complains about missing channels related to the   TIMING_DBOX_WR DBox

The acquisition process has been restarted. Please note that the cable (on the right side) connecting geophone #22 to geophone #17 doesn't lock in place (it doesn’t click), Fig 1.
Sensors mic #3 - geophone #9 and geophone #10 are all connected but currently placed near the cabinet, waiting for the east side entrance to be cleared of stored material, Fig 2.

As planned, this morning the WR new node has been switched off.

I restarted the acquisition system. The process had stopped because someone accidentally unplugged the cable connecting geophone #4 to microphone #4.
Please be careful when moving around the sensors and cables. If you trip over something, make sure everything is properly reconnected, or contact the system's referent on site.

No events have occurred on the network switches.

At that time there has been an iscsi paths rearrangement on the storage array used by the fs01 file server which exports the /virgoData and /virgoLog areas ( besides /olusers and /virgoDev) causing a temporary increase in the I/O latency which is normally transparent for the NFS clients except than for RTPC FdIO processes.

This problem has been observed many times and is due to the combination of multiple factors:

1. the load on the file server is periodically increased by client processes that are started/reconfigured to access more heavily the above mentioned disk areas.
   From this ganglia graph it can be seen that the reading load since the run break in may/june has gone to 20-40MB/s whilst it was lower than 10MB/s in the previous months and has not come back to that level yet
   Note that this kind of load onsets has been already recorded during past missing frames periods ( see this logbook entry );
   At that time heavy I/O was coming from  olserver119 and olserver114 hosts.
   Currently it is still the case, with the addition of olserver53;
    
2. the FdIO servers are particularly sensitive to I/O latency on /virgoLog since currently the logging about raw frames is handled in the same thread as  the raw frames trasmission itself.
   This causes DAQ raw frames tx buffers to overflow when writing to /virgoLog suffers a delay;
    
3. the current version of the VMware underlying hypervisor software, contrary to the one running in the previous runs, has changed the way to provide Fault Tolerance with the result that storage I/O latency cannot be improved anymore from the present level.

This morning, around 9:30h LT, I dismounted the thermocamera at the WI ZnSe viewport. Irene verified that the magnetometer placed there was put back to its correct position.

ITF found in LOW_NOISE_3 and in Science Mode.
It unlocked at 00:53 UTC, back in Science Mode from 1:42 UTC.
A second unlock occourred at 4:05 UTC, relocked at 4:51 UTC.
ITF left locked.

Guard Tour (UTC)
22:04 - 22:38
00:05 - 00:38
2:02 - 2:39 

ITF found in Science, BNS Range ~50Mpc

From 15:00UTC to 20:35UTC, Commissioning activities on Squeezing as planned

VPM
20:43UTC, PyPhaseCamB4 process restarted

Guard Tour (UTC):
17:50 - 18:24
20:06 -  20:41

We checked the alignment on the ITF that, according with the observation of the beam spots ITF on SQB1_cam0 and cam1, we find the 4MHz beat magnitude on the B1. We maximized the latest a little beat by engaging the  AA and by moving SQB1_M32 and 33 as usual. We also  checked  the RR position, 

(it seems fine) and the SQB1 positon LC_X (moved from -3400 to -3300). 

At the end he best value for the 4MHZ mag achieved was 1.52 mV (CC_phase in ASQZ) compared the initial value  1.32 mV. This relative low value is due to the low SQZ production caused by the MZ working point that we were forced to set at lower value than usual (MZ_DC offset from 0.046 V - last shift vlue - to 0.035 V) to lock it -  corresponding to about OPA_PD_DC ~ 1.68 V against the usual past value >=2.0V.

N.B.: To check if after the DETLAb humidity stabilization the  MZ alignment has been optimized

System Left with 

• SDB1_shutter open I f needed we can close tomorrow morning);

• SQB1_shutter closed; 

• SQZ_Fast_shutter closed;

Figure 1, adding the times of the DAS tuning (many hours) as blue rectanges, and the times of the RH steps (an exponential decay starting at the step) as green dashed lines. There might be a relation between the DAS tuning and the step glitch rate, there doesn't seem to be any for the ring heater steps, which means either that the glitches are independent of the RH steps, or require a much larger step to make a difference.

Today another issue with the rotators on SDB1 may explain what has happened on June 11. The automation drives the OMC shutter on channel 2 axis 1, while at the same time work was done to open the SDB1 Faraday shutter using channel 4 axis 2. There were commands sent for both within a few seconds, if the driver mixed up the commands it might have driven channel 2 axis 2, which is the north wave plate on SDB1 in front of the OMC.

The lesson here is to not drive any rotators on SDB1 by hand when the interferometer goes into DOWN, as at that time the automation closes the slow shutter, and there is only one driver acting on all the Agilis rotators and translation stages on SDB1.