On July 6, we tried to improve the AOM alignment by turning the LB_M10 mirror, located just before the AOM on the laser bench. The first order beam power generated by the AOM was measured using a calorimeter. The PCM was re-aligned. We managed to get 2.6 W on the 1st order beam. The setup to measure the 1st order power is shown in the following image.
 
It is not clear if we were actually improving the 1st order power, since the separation between the 0th and 1st order as small. We though that the 1st order beam was clipped by the prism located just before the PMC. We tried to move the prism, in order to make sure that the whole 1st order, and only the 1st order beam arrives on the calorimeter. 
This reduces a bit the RMS of the PSTAB_PDd_AC photodiode signal. However, we still don't know if the improvement was due to a better alignment in the AOM, or if the PMC alignment was improved. 
 
On july 7,
The oltf of the pstab was measured using the spectral-analyser application of the Moku-Pro. The Moku generates a chirp signal whose amplitude and frequency range can be tuned by the user. The chirp signal was injected in the "perturb" channel. 
Initially, the UGF was measured at ~45kHz. By turning the "piezo gain" controller in the image below, we increased the gain of the loop, and so the UGF. The new ugf value is 67kHz, with a 60° phase margin.
 

The morning was dedicated to weekly maintenance started at 6:00UTC, here a list of the activity reported to the control room:

- standard vacuum refill from 6:00UTC to 10:00UTC (VAC Team);
- cleaning of central building (Menzione with external firm: from 6:00UTC to 10:00UTC);
- PAY: NI payload assembly;
- INJ: IMC lock/alignment commissioning, in progress;

Air Conditioning
at around 7:55UTC I put back the injection area air conditioning system in "portata ridotta", I set back the "portata nominale" at 13:55UTC.

On July 22 the INGV team (Filippo Greco, Alfio Alex Messina, Luca Timoteo Mirabella) with the EGO support (Lorenzo Lunghini, Fabrizio Rossi)  will install the quantum gravimeter (presently at 1500W fiber lab:  https://logbook.virgo-gw.eu/virgo/?r=68692) inside the WEB experimental hall. The foreseen location is along the South wall of the building. The operation might take the entire day.

Yesterday I recovered a bit the SQZ system in view of the DAC firmware upgrade.

1) PLLs. I managed to lock only CC PLL. SC PLL need a check from site, I don't finde the beat note remotely. Main PLL: in order to relock it we shoulde change by about 2GHz the frequency of all the SQZ laser, because according to INJ crew the last FMODERR tuning moved by 1.2mm the end mirror of IMC. This is a longer work because we should also check if the CC laser in the new position will have again multimode behaviour. I did not do it yesterday

2) HD AA, and CC loop. Are perfectly working and we managed to measure 8.5dB of ASQZ and 6dB of SQZ deflecting the SQZ beam on SQB1 retroreflector

3) FCIM, FCEM and SQB1 bench are recovered both position and angular loops.

Some sidenotes:

After the upgrade from cent OS to Alma Linux I had to partially rewrite all the SQZ GUIs because the PyQt4 now are no more available. I did the porting to PyQt5

Olwin does not work now anymore. It works only on ctrl1

ITF DOWN in UPGRADING mode.

planned activities communicated to the control room:

- 08:20 - 10:10 UTC - NI tower baffle repositioning (VAC team, Gherardini)
- 13:50 UTC  - BPC and IMC loops recovery activity in Laser Lab  (Spinicelli, LaGabbe, DeRossi). UTA INJ set in Portata Nominale.

We continued to deploy the DAC1955 v3r3 firmware on all the DAC1955 boards  used from the rtpc6 .

Due to some contraints related to the EPRB phase camera, sharing the same DAC1955 board with the SPRB SBE control,  only the 2 DAC1955 boards used for the SPRB LC controls and the SPRB Quadrant galvo loops have been updated.

• On the rtpc6, the Tolm output data flow was reduced from 12.6MB/s  to 6.2MB/s 

Operations performed between 2026-07-03-07h04m45-UTC and  2026-07-03-08h07m33-UTC

• all the loops were opened during the time of the operations
• and successfully closed at the end

Below the detailled list of the operations performed:

• Use DaqBox  v17r11 for SPRB_dbox_bench and SPRB_dbox_rack server 
• SPRB_LC and SRPB_Quadrants : 2 DAC1955 boards
  • SPRB_DAC_LC_LVDT_in              : DAC1955_SN008 -  DBOX_SN005 - SPRB_dbox_bench      : rtpc6   shared between the LC and Quadrant galvo loops
  • SPRB_DAC_LC_LVDT_out            : DAC1955_SN016 -  DBOX_SN023 - SPRB_dbox_rack         : rtpc6  used only for the LC loops
  • the LC and the SBE  loops were successfully closed after the upgrade 
  • We checks that the Tolm packect, related to the Quadrant galvo loop, was correctly received by the shared DAC1955 board (SN008) 

This morning we entered the NI tower to reinstall the tower baffle that was temporarily removed at the beginning of the NI upgrade intervention. While inserting the first part of the baffle, we found that its frame was interfering with the recently installed cables, log_69271
We then skipped the installation, dismantled the component and made a small modification to the aluminum frame by adding a slot at the cable location (not visible in the attached picture).

The plan is to reinstall the baffle on monday starting at 11h LT.

Due to the change of the 22 MHz EOM with its spare we had retuned the longitudinal demodulation phase but the RF QPD NF and FF demodulation phases had still to be retuned.

The phase shifter (in the LNFS rack in piscina) was in local, so we swapped it to remote control and we tuned the demodulation phases by injecting a line at 2Hz:

• on MC tx (does a shift on EIB) --> and tuned IMC_QPD_FF_PHI  maximize the 2Hz on INJ IMC QD FF I H / V
•  on IB tz does a tilt (tx for BPC) --> tuned IMC_QPD_NF_PHI to maximize the 2Hz on INJ IMC QD NF I H / V 

With the new demodulation phases we checked again the offsets on the galvo (fig 1 and 2). 

We zeroed the AA error signals and measured again the sensing matrix with the AA loop open. 

After a manual adjustment on the H direction we left the IMC AA loop closed in full bandwidth.

Moreover, this morning we had a lot of glitches on the galvo NF H (fig 3). The corrections are quite high (more than 4V), but they are like this since months. However, it seems to have disappeared as soon as the corrections went just below 4.2 V (they are now around 3.9 V). To be monitored.

We will continue the work on monday (check the FFTs) and maybe manually look for another wp, since looking at the rfc reflection it seems that we are far away on the horizontal with respect to the past.

Below the list of the activities communicated in control room:

- DAQ: DAC1955 firmware update for EDB and SPRB;
- VAC: NI tower baffle installation;
- INJ: IMC lock/alignment recovery;

SBE
SIB2 vertical correction recovered with F0 step motors at around 6:00UTC.

We completed the DAC1955 firmware update for the EDB part:

• rtpc1:  Tolm output data flow reduced from 54.5MB/s  to 18.6MB/s
• Operations performed between 2026-07-03-09h30m38-UTC  and 2026-07-03-09h41m49-UTC

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

• EDB : 2 DAC1955 boards
  • EDB_DAC                         : DAC1955_SN046 - DBOX_SN051 - SDB_EDB_dbox_rack     : rtpc1
  • EDB_DAC_DETEEroom   : DAC1955_SN053 - DBOX_SN051 - SDB_EDB_dbox_rack     : rtpc1
  • plot showing  the successfull EDB OMC temperature stabilization and the presence of the PZT modulation line
  • we checked  that the Tolm packects are correctly received by the 2 DAC boards

We noticed that the movements of the PMC piezo are correlated with the output power of the PMC. This correlation is due to an offset in the PMC lock signal, which keeps the the transmitted signal away from its maximum. 
At 9:52 utc, we changed the offset in the ISYS_acl config file from -0.12 to -0.015 V. This set the central value of the PDH error signal to 0 V as wanted. However the PMC control loop brings the control loop signal to -22 mV instead of 0 V. So the correlation is still present after this intervention.
To correct the offset, we used the method descibed in gitlab. Instead of injecting a 270 Hz line, the injected signal is at 123 Hz (frequency written in the config file) with 0.05V amplitude.
By setting the offset level to -0.025 V, the 123 Hz line on PMC_tra was minimized. And the coherence at low frequency diminished.
 
 

We continued to deploy the DAC1955 v3r3 firmware on all the DAC1955 boards used at the NEB and WEB, execpt the ALS ones:

• NEB - rtpc8 : the 7 DAC1955 boards are updated
  • Tolm output data flow is reduced from 29,4MB/s to  5.9MB/s  
• WEB - rtpc9 : the 7 DAC1955 boards are updated
  • Tolm output data flow is reduced from 29,4MB/s to  5.6MB/s
• We faced some issues with these rptcs  as 
  • we would like to run the DAC1955 using the synchronous mode 
  • and there are some Acl's servers running at a loop frequency lower than the Tpro's one and for the ones running at the same frequency if their elapsed time is lower than the Tpro period, they are interleaved
  • until we understand that the 1PPS flag was not correctly set in the Tolm packet header 
• As consequence for the DAC1955 Tolm packet sent by an ACL's task running  with  a loop frequency lower than the Tpro's one, the DAC1955 board Tolm packet reception have been configured as asynchronous.
• For the others DAC1955 boards, the Tolm packet reception is configured as synchronous

Operations performed between 2026-07-01-09h11m50-UTC and 2026-07-01-18h43m53-UTC

• all the loops were opened during the time of the operations
• and successfully closed at the end

Below the detailled list of the DAC1955 boards updated and the related ACL's servers  at WEB

• WEB_NCAL server was already done : 2 DAC1955 boards
  • WEB_DAC_NCAL_TCS      : DAC1955_SN053 - DBOX_SN121 - SWEB_dbox_rack       : rtpc9 
  • WEB_DAC_NCAL0             : DAC1955_SN073 - DBOX_SN175 - SWEB_dbox_rack       : rtpc9
  • NCAL loops successfully closed
•  WEB_PCal_fast server  was already done : 1 DAC1955 boards
  • WEB_DAC_PCAL                 : DAC1955_SN011 - DBOX_SN049 - SWEB_dbox_rack       : rtpc9
  • PCal loop successfully closed 
• SWEB_LC  and  SWEB_SBE servers : 3 DAC1955 boards running at 400kHz  in asynchronous mode
  • SWEB_DAC_LC_LVDT_out  : DAC1955_SN044 - DBOX_SN043 - SWEB_dbox_rack       : rtpc9 
  • SWEB_DAC_LC_LVDT_in    : DAC1955_SN038 - DBOX_SN014 - SWEB_dbox_bench    : rtpc9 
  • SWEB_DAC_SBE0               : DAC1955_SN039 - DBOX_SN062 - SWEB_dbox_rack       : rtpc9
  • loops succesfully closed. The TX and TY position changed as we restored the ones of the configuration file 
• SWEB_PSD_sensing server : 1 DAC1955 board  running at 400kHz  in asynchronous mode
  • SWEB_DAC_PSD                 : DAC1955_SN035 - DBOX_SN014 - SWEB_dbox_bench     : rtpc9
  • we checked  that the Tolm packect are correctly received by the DAC board

Below the detailled list of the DAC1955 boards updated and the related ACL's servers  at NEB

• NEB_NCAL server was already done : 2 DAC1955 boards
  • NEB_DAC_NCAL_TCS         : DAC1955_SN018 -  DBOX_SN119 - SNEB_dbox_rack       : rtpc8
  • NEB_DAC_NCAL0                : DAC1955_SN006 -  DBOX_SN118 - SNEB_dbox_rack       : rtpc8
  • we checks that the Tolm packect are correctly received by the DAC boards 
• NEB_PCal_fast server and NEB_NNC_Tilt server   were already done : 1 DAC1955 boards
  • NEB_DAC_PCAL                   : DAC1955_SN121 - DBOX_SN035 - SNEB_dbox_rack       : rtpc8
  • PCal loop successfully closed 
• SNEB_LC  and  SNEB_SBE servers : 3 DAC1955 boards  running at 400kHz  in asynchronous mode
  • SNEB_DAC_LC_LVDT_out    : DAC1955_SN031 - DBOX_SN034 - SNEB_dbox_rack       : rtpc8
  • SNEB_DAC_LC_LVDT_in      : DAC1955_SN003 - DBOX_SN013 - SNEB_dbox_bench    : rtpc8
  • SNEB_DAC_SBE0                 : DAC1955_SN102 - DBOX_SN127 - SNEB_dbox_rack       : rtpc8
  • loops succesfully closed
• SNEB_PSD_sensing server : 1 DAC1955 board  running at 400kHz  in asynchronous mode
  • SNEB_DAC_PSD                   : DAC1955_SN007 - DBOX_SN013 - SNEB_dbox_bench     : rtpc8
  • we checked  that the Tolm packect are correctly received by the DAC board

On Tuesday morning we completed the realignment of the BPC loop. We started by zeroing the corrections sent to the actuators and centering the DC offset on the amplifier, in order to maximise the actuator dynamics.

With the PMC locked and the BPC loop closed, we used the M6 and M8 mirrors on EIB to center the BPC QPDs. The loop closed easily in full bandwidth, with less than 1V of correction per DoF. The power measured at the output of EIB_M9 was around 29W, similar to what we measured before the April intervention.

We then closed the BCP at the usual setpoints, and coarsely realigne MC and SIB1 in order to relock the IMC. Despite the presence of peaks above 8-10W (the power threshold for the rampauto) we didn't succeed in relocking.

We found a phase shift of almost 45° on the demodulated error signal, most probably due to the swap of the 22 MHz EOM with its spare. The new value for the phase is 2.85. A finer tuning will likely be performed once the IMC recovery is complete.

Today, the OLTF of the IMC under these new conditions was measured (see Fig. 1), showing an UGF of less than 90 kHz and ~23° of phase margin, significantly lower than the last measurement at the end of April.  This may be a direct consequence of the chiller and the slave laser issue from early May, with the SL not being properly seeded by the ML beam. For the time being, we will not work on improving the SL loop.

With the IMC locked, we checked the IMC working point (new value: −0.85), realigned the IMC cavity, and measured the new AA sensing matrix and angular galvo offsets. The AA has been closed in full bandwidth. Moreover, the RFC locked directly after closing the IMC AA.

Some remarks, though:

• The longitudinal working point is smaller with respect to the last measurement.
• The AA error signals show quite large offsets across all channels.
• The IBz loop, which links BPC_X to the Z position of the SIB1 bench when the IMC is locked, is currently not working. The BPC X DoF, however, works correctly when using the BPC QPD error signal. For the time being, we have manually adjusted the X setpoint to minimise the IBz signal. We will investigate further to identify the origin of the problem.

This morning, we tested a Güralp 3ESPC seismometer at the North end building. The sensor has been purchased for the deployment of the external environmental monitoring stations.

The Güralp 3ESPC was temporarily connected in place of the NEB reference Güralp seismometer and installed close to the electronics racks, Figure 1.
A dedicated interface device was developed to lock, unlock, and center the sensor masses, Figure 2. During the test, the masses were first unlocked to verify the correct operation of the instrument and were then locked again using the same interface.

Figure 3 compares the spectra measured by the tested seismometer (blue curve, ENV*SEIS_*) and by another Güralp seismometer (orange curve, ENV*SEIS*T*) installed close to the tiltmeter. The two sensors show a very good agreement at low frequencies, with high coherence below approximately 5-10 Hz. At higher frequencies, the tested sensor exhibits a slightly higher noise level, most likely because it was temporarily installed close to the electronics racks. 

Overall, the test confirms the correct operation of the seismometer.

The change in SDB1 TX and TY set point is understandable. After the update the set points are exactly as written in the configuration file. Before the update the set points were most likely still the floating set points that are corresponding to where the beam actually was before the interferometer beam was disable a few months ago. A drift of a few urad is usual between the static set point and the floating set points.

ITF DOWN in UPGRADING mode.

Activities communicated to the control room:

• NI and WI instrumented baffles checks (Ballester, Gargiulo, Gherardini, Pasqualetti)
• MC cavity lock (De Rossi, Gosselin, Lagabbe, Spinicelli)
• Seismometer test at NE (Gherardini, Fiori, Tringali)
• DAC1955 v3 firmware deployment on rtpc8/9 (SWEB) (Masserot)
• NI Payload preparation (Vocca, Travasso)

From Monday June 15 to Thursday June 18, we worked in the installation of new instrumented baffles and the replacement of the existing BafFlanges in the NI and WI towers. In all tasks in the tower, the IFAE team was assisted by Julien Gargiula, Nicola Menzione, Cecilia Zaza. Feedthrough and internal cabling were installed by Fabio Gherardini.

On June 15 morning we proceeded to several tasks in parallel:

• Install drawers in NI rack #2, unit 32 (David). (image 1)
• Assemble white boxes (Otger). (image 2)
• Cleaning of the big structure, installation bars and several small pieces (Alex and Lluïsa-M. with the guidance of Nicola and Cecilia). (image 3)
• Add PT100 and "clips" to baffles preassembled on May 4/5. (Noel, Jose & Pepe).
• Run electronic tests (again): all OK, but one cable found faulty (David, Pepe), taken to Vincenzo for repair (Lluïsa-M.).
• Replace crooked antenna (Pepe).
• Disassemble NI BafFlange (Noel & Jose).
• Prepare everything for the afternoon installation in the tower (Alex, Noel & Jose).

In the afternoon:

• Move equipment to NI rack (David & Otger).
• Move the instrumented baffle to NI tower. (images 4 and 5)
• Installation finished by 5 pm (Noel, Jose & Alex). The baffle is measured to be at 10 mm (uncertainty of +- 1 mm) from the flange with a deviation from the vertical plane of +- 0.1°. (image 6)
• Equipment moved to NI (Pepe, David and Otger).

On June 16 morning:

• Install the cable connecting the midpoint to the feedthrough (Fabio).
• Otger and David read the first data. Everything looks OK.
• Alex, Noel, Maria & Piernicola measure the transfer function (TF) with accelerometers. (images 7 and 8)
• In parallel Jose and Pepe assemble the second baffle. (image 9)
• In parallel Otger and David discuss computing requirements with Erin Seder.

In the afternoon:

• Once we get the OK from Maria regarding the TF data, the new BafFlange is installed in the NI tower (Noel, Jose and Alex). (image 10)
• In parallel Alex and David check electrical connections of the second baffle in the clean room.
• Install external cabling of the WI (Pepe).

On June 17 morning:

• Nicola and Cecilia clean the WI tower.
• Once finished, Alex, Noel and Jose disassemble the WI BafFlange and install the second instrumented baffle. The baffle is measured to be at 10 mm (uncertainty of +- 1 mm) from the flange with a deviation from the vertical plane of +- 0.1°. (image 11)
• Pepe and David check that power is reaching the baffle properly.
• Otger and David start readout tests.

In the afternoon:

• Struggling with WI baffle readout, half baffle does not produce signal. Problem due to external cable, fixed. Everything is OK now. Install WI inner tube and back baffle.

On June 18 morning:

• (Noel, Alex and Piernicola) TF measurements of the WI baffle. (image 12)
• Once we get the OK from Piernicola regarding the TF data, the new BafFlange is installed in the WI tower (Noel, Jose and Alex). (images 13 and 14)
• Installation in the towers finished. (images 15 and 16)

In the early afternoon:

• Experiencing problems to set up the WI system, requiring several attempts to get it. Once connection is obtained there are no data lost and data make sense. External cables checked and found OK. Will request checking the cable connecting the midpoint to the feedthrough and continue the debugging remotely.

 
The problems disappeared after replacement of the mid connector. See entries  https://logbook.virgo-gw.eu/virgo/?r=69271 and https://logbook.virgo-gw.eu/virgo/?r=69276.