ITF found in DOWN State and COMMISSIONING Mode.
All times are UTC.
05:12 - 09:00 DAQ: EPRB, SIB2, ALS DAC firmware update (Masserot, #69668).
09:26 - 10:38 PSTAB 50Hz harmanics feed-forward preparation, turned on at 10:18, and it will be turned of at the end of the day (Was, #69666).
10:37 CITF relocked only at 1F stage, the handoff to LOCKED_ARMS_BEAT_DRMI_3F caused several unlocks.
ITF left in COMMISSIONING Mode and LOCKED_ARMS_IR State.
 

We continued to deploy the DAC1955 v3r3 firmware on the DAC1955 boards by completing the SPRB part and running it on the SIB2 and ALS subsystems.

• SPRB_rtpc : DAC1955 firmware completion: 1 DAC1955 board updated, the one use for SBE and Phase camera
  • Tolm output data flow reduced from 12.6MB/s to 2.56MB/s  
• SIB2_rtpc : the 4 DAC1955 boards are updated
  • Tolm output data flow reduced from 16.78MB/s to  3.43MB/s
• ALS: the 3 DAC1955 boards are updated 
  • ALS_NEB_rtpc: Tolm output data flow reduced from 4.2MB/s to  0.34MB/s
  • ALS_WEB_rtpc: Tolm output data flow reduced from 4.2MB/s to  0.31MB/s
  • ALS_CEB_rtpc : Tolm output data flow reduced from 4.2MB/s to  0.53MB/s

Operations performed between 2026-08-28-05h30m03-UTC and 2026-08-28-09h12m26-UTC

• all the loops were opened during the time of the operations and successfully closed at the end
• At the end the ITF was relocked at LOCKED_ARM_BEATING  after the re-aligment of the ALS_CEB phototiodes used to acquire the NARM and WARM beating beams

Below the detailled list of the DAC1955 boards updated and the related ACL's server

SPRB :

• SPRB_SBE and EPRB_PC : 1 DAC1955 board
  • SPRB_DAC_SBE0 : DAC1955_SN004 - DBOX_SN025 - SPRB_dbox_rack : shared DAC1955 board
    • SPRB_SBE server: ch00-ch05 : 6 channels
    • EPRB_PC server  : ch06-ch07 : 2 channels
• We checked  that the Tolm packects are correctly received by the DAC board
• The SPRB_SBE loops were successufly closed after the update 

SIB2:

• SIB2_LC  and SIB2_SBE : 3 DAC1955 boards
  • SIB2_DAC_LC_LVDT_in : DAC1955_SN005 - DBOX_SN001 - SIB2_dbox_bench  
  • SIB2_DAC_LC_LVDT_out : DAC1955_SN015 - DBOX_SN020 - SIB2_dbox_rack 
  • SIB2_DAC_SBE0 : DAC1955_SN009 - DBOX_SN047 - SIB2_dbox_rack
  • We checked  that the Tolm packects are correctly received by the DAC boards
  • The SIB2_LC and SIB2_SBE loops were successfully closed after the upgrade
• SIB2_Quadrants :  1 DAC1955 board
  • SIB2_DAC_galvo : DAC1955_SN137 : DBOX_SN101 - SIB2_dbox_bench
  • We checked  that the Tolm packects are correctly received by the DAC board

ALS

• ALS_NEB_BPC: 1 DAC1955 board
  • NEB_DAC_ALS0 :  DAC1955_SN062  : DBOX_SN066 - NEB_ALS_dbox
  • We checked  that the Tolm packects are correctly received by the DAC board
  • The IR PSTAB loop was successfully closed after the upgrade
• ALS_WEB_BPC: 1 DAC1955 board
  • WEB_DAC_ALS0 : DAC1955_SN002 : DBOX_SN050 - WEB_ALS_dbox
  • We checked  that the Tolm packects are correctly received by the DAC board
  • The IR PSTAB loop was successfully closed after the upgrade
• ALS_CEB_BPC and LNFS_RAMSs :  1 DAC1955 board
  • CEB_DAC_ALS : DAC1955_SN145 : DBOX_SN086 - CEB_ALS_dbox : shared DAC1955 board
    • ALS_CEB_BPC : ch00-ch03 : 4 channels 
    • LNFS_RAMs     : ch04-ch07 : 4 channels
  • We checked  that the Tolm packects are correctly received by the DAC board
  • The PZT NARM and WARM loops were successfully used to increase the NARM_DC and WARM_DC signals
    • Operations performed between 2026-08-28-09h10m43-UTC and 2026-08-28-09h12m26-UTC  

After the issue with the EIB actuators of August 14th  and the several interventions to mitigate the problem, the green beam on the EIB got a bit misaligned, especially on the North arm path (Fig. 1). As a consequence, the yesterday attempt to lock the arms on the beating did fail. 

In the afternoon of yesterday,  we used the picomotors on EIB to realign both path (fig2). For the time being, we didn't realign the ALS_CEB_BPC, as we want to perform it with the CEB_GREEN off (to mainly align on the ARM signals), but for the moment is not possible to use the flip mirror without unlocking INJ.

To be noted that at first attempt, the picomotor were not responding, even with a restart of the server. We needed to physically unplug and replug their power supply in the IER to get them working. Being the second time in few weeks that this happens, we will investigate wheter it is due to an hardware problem. 

This morning I have corrected the logic error at 10:16 UTC.

Figure 1. Shows the safety working properly, the FF corrections visible in INJ_PSTAB_NOISE and the FF tracking loop start at 10:17:30 UTC, 20 seconds after the RFC locks, despite the ENABLE flag being activated since at least 10:17 UTC.

Enabled also the 250Hz FF, and leaving it on for the day to see if any issues arises over several hours. I will disable the PSTAB FF loop at the end of the day as a precaution for the weekend.

In addition to the two action reported, the "energy safe" option has been selected yesterday too (see fig. 1). 

Other than the usual 1Hz comb noise,  present with those chiller when the safe mode is not selected, we could see a sawtooth oscillation on T of the chiller and the neoVAN diodes, with a period of about 11min (see fig. 2).  
The oscillation went away as soon as we changed the operation mode.

Yesterday evening I have tried to add a safety to the feed-forward to automatically turn it off when RFC_TRA_DC goes below 2V (unlocks). 

Figure 1 shows the result just after restarting the ISYSnoise process with the changes. The FF correction (eventually dominating the RMS of INJ_PSTAB_NOISE) starts immediately with a ramp of 20 seconds, instead of starting with a delay of 20 seconds after the RFC locks. I need to correct the logic of the safety.

---------

16:40 UTC restarted ISYSnoise to add a check that disables the 50Hz
harmonic FF when the RFC is not locked. Not fully certain if it works
as the timer is 20s while the 50Hz FF loop started acting only 10s
after the RFC locked.

17:01 UTC (5min) 250Hz FF enabled and stable

17:16 UTC disabling 50Hz and 250Hz FF
 

ITF found in COMMISSIONING Mode and DOWN state, with MISALIGNED_ALL_BUT_NI state on ARMS_LOCK node (equal to SINGLE_BOUNCE_NI state from ITF_LOCK).

Planned activities:
- First check on DET HWS and SLED beam (Lumaca, Corubolo), concluded at 11:10 UTC.
- Opening of Cryo Valves (VAC team), performed at 08:49 UTC.
- New position for GRAS microphone on Injection Tower, concluded at 09:15 UTC.
- Spare Neovan Chiller tuning in EERoom (Lagabbe, Zaza), performed at 12:00 UTC.

In order to allow the TCS activity:
- I set UTA DET in Portata Nominale.
- I recovered all metarton nodes in standard state.
- Thanks to Ruggi we realigned and relocked cavities.
- I recovered the SDB2 vertical position via stepping motors and close SDB2_SBE loop.
- Thanks to Gouaty we recovered the SDB2 position and close LC loops.
- I set ITF in SINGLE_BOUNCE_NI with SR manually aligned.
- Upon concluded the activity (11:10 UTC) I set again UTA DET in Portata Ridotta and re-misaligned SR.

I tried to move on with the lock acquisition up to ACQUIRE_DRMI in order to perform the usual cross-alignment, but unfortunately ITF unlocked at LOCKING_ARMS_BEATING while Engaging boost filter #1. Investigation in progress on EIB (Spinicelli).

ITF now in standard state in LOCKED_ARMS_IR.

This afternoon around 14h20 local, we increased the chiller temperature setpoint from 16 C to 17 C, and increased the water flow.

This morning between 08:30 and 09:15 UTC we moved the microphone from the west side of the INJ tower (nearby the EEroom, Fig1), see #69458. 
We placed it on the terrace near to the Injection Tower on the west side close to the already present Netwonian microphone (Fig2).
The channel is is unchanged: ENV_CEB_LLR_MIC (#69466).

List of corrections deployed with this update:

• RESOLVED: entries being overwritten by a following one, or disappearing after being posted
  • When creating a new entry, the logbook asked the database for the identifier of the record it had just created, by looking up the highest existing entry for that author. This stopped being reliable when the database was moved to the clustered configuration: since reads and writes were split between nodes, the lookup could be answered by one that had not yet received the new record, and returned the identifier of the author's previous entry instead. The new text was then written onto that entry, or refused altogether if that entry was no longer editable.
  • The identifier is now taken from the insertion itself and the database routing has been corrected on the server side.

• RESOLVED: logbook unreachable or timing out
  • A single entry had been recorded as a comment to itself, a side effect of the problem above. Rendering it made the page recurse without end and exhaust the database connections.
  • Storing such a record is now refused, and the comment display stops on any circular reference. If the server refuses to save an entry for any reason, the editor now shows a warning and keeps the text, instead of returning to the main page as if the entry had been posted.

For comparison, logbook entry 64819 contains an image of the HWS-DET SLED beam acquired with a CCD camera in July 2024. The beam observed today appeared qualitatively similar to the one shown in that entry.

Is attempted a measurement of sound transmission between the CEB hall and the labs INJ and DET. The white acoustic noise injection of July 28th is used.

The used reference microphones are:

• "outside" (CEB hall): ENV_CEB_MIC
• "inside" INJ clean room (on Laser Bench): ENV_LB_MIC
• "inside" DET clean room (on EDB): ENV_EDB_MIC

The averaged ASD of the reference microphones are computed first (Figure ...), then converted into Sound Pressure Levels in 1/3rd Octave bins (Figures...), finallly the "transmission loss" (here called "isolation") between the hall and the two labs is computed as the difference of the SPL of the outside and the SPL of the inside mics (Figures ...). On the same figure is reported the transmission loss requirement of the actual clean rooms, from VIR-0357A-12. All units are acoustic dB:

Lout = np.where(Lout > LoutQ, Lout, np.nan)
Lin  = np.where(Lin  > LinQ,  Lin,  np.nan)
Liso = np.full_like(Lout, np.nan)
mask = Lout > Lin
Liso[mask] = Lout[mask]-Lin[mask]

Note that this evaluation is not complient with the ISO standards (UNI EN ISO 16283-1:2018) which would require multiple microphones properly located and as well as a proper source. Also, no correction is applied for the reverberation effect (as foreseen by ISO). Being the source (loudspeaker on DET terrace) is much closer to the DE then to the INJ lab, there is a obvious bias overestimating the INJ lab isolation, while underestimating the DET lab isolation. Also, inside microphones are placed under some cover (plexiglass for the LB, and metallic for the EDB) which cause an overestimation of isolation above some 100Hz, or 1kHz. However, despite these limitations, these measurements can be used as future reference, if the same source and microphones location is adopted.
Liso values are printed in the attached .txt files.
 

We entered the DET lab at approximately 8.00 UTC. For the duration of the activity, Nicola set the DET lab HVAC system to high-speed mode. 

We first unplugged the power supply and all the cables of the link located behind the HWS. We then removed the HWS camera and installed the CCD camera in its place, restoring all the required connections (see Fig. 1). 

Afterwards, we went to the Detection Electronic Equipment Room and physically switched on:

• the HWS-DET power supply

• the DET SLED power supply

We then attempted to connect to the CCD camera. The camera initially had to be reinitialised, after which the connection was successfully established. We set the SLED-DET voltage to 1.0 V and started to observe a signal on the camera. 

Once Nicola confirmed that the required interferometer configuration had been established, the conditions were as follows:

• suspended DET bench correctly positioned, thanks to Nicola and Romain;

• SR, BS and NI aligned

• WI, WE and NE misaligned

We increased the SLED-DET voltage to 1.2 V and observed the beam clearly on the CCD camera. When the DET flip mirror was closed, the beam disappeared from the camera, as expected (see Fig. 2). 

The DET SLED beam appeared to reach the NI mirror correctly and return to the sensing camera without any significant clipping.

The following actions still need to be performed:

• reinstall the DET HWS camera in place of the CCD camera

• perform the same type of check on the INJ HWS/SLED system

We left the DET SLED turned on at 1.2 V and the CCD camera ON.

On Monday I forgot the restore the nominal position in TX of the SDB2 bench after the TX scan. This means that the bench was left by mistake in position TX = -420 urad for the past 3 days. I restored the nominal setpoint TX= -280 urad today at 09h03 utc.

Yesterday, 2026-08-27, the IRIG-B signal was disabled in the 100MHz-IRIG-B timing distribution to check the phase noise:

• 2026-08-26-07h28m08-UTC       Command '100MHz-IRIGB:irig off' executed
• 2026-08-26-07h45m09-UTC       Command '100MHz-IRIGB:irig on' executed

Looking at the LNFS and EOM 6MHz, 8MHz and 56MHz signals, I was surprised by the shape of their FFT's phase 

• This plot compares them when the IRIG-B distrubution is disabled for  the 2026-02-10-18H00m-UTC (purple) and the  2026-08-26-07h30m-UTC (blue)
• This plot compares them when the IRIG-B distribution is enabled for the  2026-07-10-00h00m_UTC (puple) and the  2026-07-16-00h00m-UTC (blue), after the replacement of the LNFS generator by a spare

According to these plots, the spare LNFS seems to be more noisy and with more lines

The chiller of the neovan electronics stopped working at around 14:00 utc. Probably due to normal device aging.

This afternoon we exchanged the chiller with the spare that was in the optics lab. The serial number of the old chiller is on the pictures attached to this post.

PS: In the chiller water tank, we found some 'sand' which is probably some metal oxide and particle coming from the electronic devices and tubing.

Today we started the activity on the NI CO2 bench at approximately 8.00 UTC. Continuing to following the steps described in issue #186, we performed the NI outer ring checks: 

• We removed the mask from its nominal position and installed SPIRICON 2 in its place, using the post holder

• We reduced the power in the DAS OUT branch to limit the power reaching the SPIRICON 2. We initially encountered an issue with the “TCSAgilisRot / Move NI_CO2_OUT” waveplate; to recover its operation, we stopped and restarted the TCSAgilisRot process from VPM

• We checked the intensity distribution of the outer ring

• We observed mainly a horizontal asymmetry, together with a very small vertical one. We therefore adjusted M10 to obtain a more uniform intensity distribution. Figure 1 shows the outer ring profiles before and after the adjustment. 

After completing the adjustment, and before reinstalling the mask, we acquired an image of both NI DAS rings (Figure 2) with SPIRICON 2. The two rings appeared correctly aligned.  

We then:

• Removed the SPIRICON 2 from mask position and we put back the mask 

• Performed a quick check with SPIRICON 1 at the CINOGY position to verify that the mask correctly covered the hot spot.

Having completed the power distribution checks, we removed both SPIRICON cameras from the bench and proceeded with the on-bench alignment checks.

Using the Thermal Camera acquisition system, we observed the actuators and checked the relative alignment (DAS rings and CH). We found  a small relative centering offset between the inner and the outer rings, along the vertical direction, which was corrected by applying a very small adjustment to the recombiner. Figure 3 shows the final alignment between the DAS OUT halo and the DAS IN ring; the DAS OUT halo was used because it provides a clearer reference for evaluating the centering.

After daily meeting, we also checked the alignment of the CH with respect to the DAS rings. No adjustment was required. Figure 4 shows the final alignment between the DAS OUT halo and the CH; again, the halo was used as the clearer centering reference. 

After completing the checks, all flip mirrors were restored to their standard positions: the DAS IN, DAS OUT, and CH flip mirrors were closed to block the beams on the bench, while the CINOGY and Thermal Camera flip mirrors were left open to allow the beam to propagate towards the interferometer if required. The NI bench enclosure was then closed.

The activity on the NI bench ended at approximately 14:30 UTC. 

The power-distribution and alignment checks on the NI CO2 bench can therefore be considered complete. 

ITF found in COMMISSIONING Mode and DOWN state, with MISALIGNED_ALL_BUT_NI state on ARMS_LOCK node (equal to SINGLE_BOUNCE_NI state from ITF_LOCK)

- planned activity:
- CO2 bench checks (Lumaca, Corubolo). Still in progress...

ISYS
16:04 UTC - Neovan chiller switched OFF for unknown reason. Afetr a check, Gosselin discovered a problem on it. He is going to replace it with a spare one.

SBE
SPRB vertical position recovered via stepping motors.

This entry is posted with a delay because the logbook was temporarily unavailable.

Today, we started the activity on the WI CO2 bench at approximately 12:30 UTC (a reference entry was posted earlier, but it does not appear in the logbook), continuing to following the steps described in issue #186, performing the outer ring checks:

• We removed the mask from its nominal position and installed SPIRICON 2 in its place, using the post holder

• We reduced the power in the DAS OUT branch to limit the power reaching the SPIRICON 2

• We checked the intensity distribution of the outer ring

• We observed mainly a horizontal asymmetry, together with a very small vertical one. We therefore adjusted M10 to obtain a more uniform intensity distribution. Figure 1 shows the outer ring profiles before and after the adjustment. 

After completing the adjustment, and before reinstalling the mask, we acquired an image of both WI DAS rings (Figure 2) with SPIRICON 2. The two rings appeared correctly aligned. 

We then:

• Removed the SPIRICON 2 from mask position and we put back the mask 

• Performed a quick check with SPIRICON 1 at the CINOGY position to verify that the mask correctly covered the hot spot. 

Having completed the power distribution checks, we removed both SPIRICON cameras from the bench and proceeded with the on-bench alignment checks.

At this point, we looked at the actuators through the Thermal Camera data acquisition system, to relatively align all the WI CO2 actuators (DAS rings and CH) one to each other. Figure 3 shows the final DAS OUT-CH alignment. 

After completing the checks, all flip mirrors were restored to their standard positions: the DAS IN, DAS OUT, and CH flip mirrors were closed to block the beams on the bench, while the CINOGY and Thermal Camera flip mirrors were left open to allow the beam to propagate towards the interferometer if required. The WI bench enclosure was then closed.

The activity on the WI bench ended at approximately 15:10 UTC. The WI CO2 bench was secured and the white curtains were closed (69644).

The power-distribution and alignment checks on the WI CO2 bench can therefore be considered complete.


We then moved to the NI CO2 bench to begin the same checks previously performed on the WI bench. The activity started at approximately 15:15 UTC, following the procedure described in issue #186, beginning with the inner ring checks: 

• We installed SPIRICON 1 in the CINOGY position

• We reduced the power in the DAS IN branch to limit the power reaching the SPIRICON 1 and followed the beam along the CINOGY telescope path.

• We checked the intensity distribution of the inner ring.

• We observed mainly a horizontal asymmetry, together with a very small vertical one. We therefore adjusted L3_tras to obtain a more uniform intensity distribution. Figure 4 shows the inner ring profiles before and after the adjustment. 

At approximately 16:30 UTC, we stopped the activity and secured the NI bench. The CO2 laser beams were blocked on the bench using the flip mirrors. SPIRICON 1 was switched off, covered, and left in position, and the bench enclosure was closed.

The activity will continue tomorrow with the outer ring power-distribution checks and the on-bench alignment checks.

Activities on the WI CO2 bench have finished. The enclosure and the white curtains were closed at approximately 15:10 UTC.

Activities continued on the NI CO2 bench until 16.30 UTC.

Following the addition of the RFC Audio channels to rtpc19 ( https://logbook.virgo-gw.eu/virgo/?r=69642 ), I have replaced them as an error signal for the PSTAB 50Hz harmonics feedforward. After some tuning this has worked well at least as measured with the existing diagnostic channels.

Figure 1 shows the performance around the 50Hz line, in purple are reference data with the FF off and in blue with the FF on. The line is removed from RFC PD1 Audio which is in loop, and also RFC PD2 Audio which is out of loop. The two PDs are connected to the same photodiode mezzanine, so one could argue that they just see a common sensing noise and not the power stability itself. The line disappears also from the B2 photodiode, where it is much more faintly visible than in July, because the power on the PD is 10 times smaller, the PR parking position must be slightly different. Most importantly it is reduced also from the RFC Tra photodiode, which is read out of vacuum by separate electronics, confirming a true improvement in the 50Hz, while not being able to quantify the improvement as it is affected by its own 50Hz contamination. On the PSTAB PDs there is no significant difference, as those are contaminated by additional sensing noise at 50Hz, both in loop, and most likely in the readout to the ADC. 

Figure 2 shows the performance for the 250Hz line. Again it is well removed from both RFC PDs, and the improvement on the RFC Tra photodiode is much clearer with a factor 10 decrease, while B2 does not have enough signal to give any information.

Leaving the FF off. The next step should be to automate switching of the FF loop when the RFC unlocks, as it may misbehave without the RFC locked, and then perform some longer duration tests of the FF and FF tracking loop stability.

-----------------------------------------------------

around 12:38 - restarting ISYSnoise process to add RFC as possible
inputs to PSTAB 50Hz harmonics cancellation
12:40 UTC (4min) reference time

spent a long time adjusting the starting parameters and the FF
tracking parameters. Especially for the 250Hz where a delay of 90
degrees was needed to make the I quadrature act on the gain, and the Q
quadrature on the phase.

14:09 UTC (4min) FF on with tracking enabled and in steady state

14:15:20 UTC disabling FF and FF tracking
 

ITF found in COMMISSIONING Mode and DOWN state, with MISALIGNED_ALL_BUT_NI state on ARMS_LOCK node (equal to SINGLE_BOUNCE_NI state from ITF_LOCK)

Activities communicated in control room:

• RFC_PD{1,2}_Audio sent from SIB2_rtpc(rtpc18) to INJ_rtpc(rtpc19);
• from 6:00 UTC to 10:30 UTC standard planned maintenance; 
• from 12:30 UT
• work on WI CO2 benches, still in progress

ITF left as it was found.

The SIB2_Photodiodes server configuration has been updated to send the  RFC_PD{1,2}_Audio channels to the INJ_rtpc

The ISYSnoise server configuration has been update to read the SIB2_RFC_PD{1,2}_Audio channels

Operations performed between 2026-08-25-07h18m43-UTC and 2026-08-25-07h23m38-UTC