20/05

Yesterday, while relocking the SL, we noticed that the reflection was quite low: 0.22 V instead of the usual 0.38 V.
When the NeoVan was seeded only by the ML, we obtained higher power than when it was seeded with both the ML and SL.
The SL PUMP DC signals, which monitor the pumping diode power at the output of the fiber in the SL head, were also higher.

This indicates a general misalignment of the SL cavity that needed to be cured. 

Since the temperature of the NeoVan was increasing, we decided to slightly reduce the pumping diode current overnight while keeping the SL running, hoping that thermalization during the night would improve the situation.

21/05

No thermalization effect was observed overnight.

In the morning we held a meeting with Walid and Margherita to analyze the situation. We agreed that the beam of the pumping diodes needed to be realigned inside the crystals. Since the power was already quite high, we were expeting a slight misalignment that could be recovered by ajusting the lenses in front of the cavity (at least as a first try).
We then went to the laser lab in the afternoon to perform the adjustment. By tuning the vertical and horizontal position of the lenses, we managed to recover the reflection signal up to 0.32 V.
We did not fully recover the nominal value, which was quite expected since we only had a limited number of degrees of freedom available compared to the full possible misalignment that may have occurred.

We also measured the slave locking bandwidth (14:51:02) and found 1.15 MHz, significantly lower than the 2.1 MHz measured last time we did it. This further confirms the presence of a misalignment of the cavity. 
Also, visually, we observed that the beam was not propagating correctly through the optics toward the NeoVan, so we decided to flip the mirror located between the SL and the amplifier. 

Peltier situation:

When the safety interlock triggered on 08/05, the PID temperature controllers did not stop sending correction signals. This was verified this morning by manually triggering the safety system.

Our hypothesis is that, during the afternoon of the 08/05, without cooling from the chiller on the hot side and while the system was still attempting to cool the crystal, the Peltier element of Crystal 1 was receiving 2A and experienced an overall temperature increase. This eventually resulted in a general temperature rise of both peltier, both crystals and likely the whole cavity. 

Activities communicated to the control room:

WE vacuum control unit and CEB cryotraps maintenance (Erbanni, Francescon, Macchia, Pasqualetti)
SL electronics checks (De Rossi, Gosselin, Lagabbe, Spinicelli)
Finalization of the changes to the main building's air conditioning system (Infrastructure Group)

 We deployed the DAC1955 v3r3 firmware on the 3 DAC1955 boards used  for the SDB2 bench local controls

• SBE: DAC1955_SN22 located in the DBOX_SN27-slot2 and managed by the SDB_EDB_dbox_rack server 
• LC: 
  • LVDT_in: DAC1955_SN69 located in the DBOX_SN106-slot2 and managed by the SDB2_dbox_bench server
  • LVDT_out:  DAC1955_SN19 located in the DBOX_SN28-slot3 qand managed by the  SDB_EDB_dbox_rack server 
• these DAC1955 boards are now running at 400KHz instead of 100KHz with new facilties for the channel management (see  DaqBox DAC1955 documentation for the details ). The DAC1955 anti-image filter is  a 3rd order with a FCut at 20KHz

The related DBox servers have been updated with the v17r9  the 2026-05-13 and then with v17r10 release the 2026-05-15

These plots show the trend of the relevant signals from the 2026-05-10 to the 2026-05-21 for

•  SBE_SDB2  x,y,z and act1,act2,act3,act4  channels
•  SDB2_LC txyz and txyz_corr channels 

The operations have been done over 1 week, from the 2026-05-12 to the 2026-05-20 

• 2026-05-12-09h57m47-UTC  to 2026-05-12-15h33m36-UTC 

  • DAC1955 v3r3 firmware installation on the related DAC1955 mezzanines
  • Use DBox server  v17r9  release for SDB_EDB_dbox_rack and SDB2_dbox_bench servers
  • the DAC1955 data reception  was set in asynchronous mode and the data policy extension is set to use the zero policy for this version of the DBox server
  • SDB2_SBE and SDB2_LC configuration files update 
    • for SBE and  LC_LVDT_out , the DAC1955 channels are built at 10KHz
    • for the LC_LVDT_in  the DAC1955 channels are built at 50KHz
  • During the operations , we faced with some issues due to the DBOX server compatibility. As consequence all the DBoxes managed by the SDB_EDB_dbox_rack and SDB2_dbox_bench servers were reconfigured.
  • At the end the SDB2_LC loops were successfully closed and the SDB2_SBE ones too with the tracking disabled
• 2026-05-15-04h53m01-UTC to 2026-05-15-05h37m55-UTC
  • Looking at the FFT of LVDT_in and LVDT_out channels; one can see a new line around 36Hz  only on most of the LVDT_out channels  and the presence of the 10KHz line on all the LVDT_out channels
  • This line come from the beating of the FL_H-BR-V line at 9964.3Hz and the 10KHz line due the use of the zero extension policy.
  • Today one way to fix this issue, was to generate the LVDT_out at 50KHz ( LVDTs plots 0Hz-1KHz, 9.6KHz-10KHz ) :
    • SDB2_LC configuration updated to build the LVDT_out DAC channels at 50KHz 
    • LVDT_out DAC1955 reconfiguration to use the new TolmPacket 
  • To avoid the same issue for the SBE DAC channels, they are build at 50KHz too
  • At the end the SDB2_LC loops were successfully closed and the SDB2_SBE ones too with the tracking enabled this time,as it s the default
• 2026-05-20-07h18m46-UTC  to 2026-05-20-08h39m34-UTC
  • Enable the use of the synchronous mode for  the 3 DAC1955 used for the SDB2 SBE and LC control loops
  • the related parts of the DBox servers, SDB_EDB_dbox_rack and SDB2_dbox_bench, have been updated  by adding for the  DBOX_DAC1955_INPUT_PACKET keyword  "sync" and a "delay value" measured using the command /virgoApp/DaqBox/v17r10/Linux-x86_64-CL7-4.14.111-hal-3-rtai-5.2/DaqBoxCtl.exe -s -m   -e 
  • After these operations,  the SDB2_LC loops were successfully closed and the SDB2_SBE ones too with the tracking enable

Note: the DAC1955 synchronous mode has been deployed  to NCAL NE and WE   DAC1955 boards too :

• WEB NCAL: operations performed between  2026-05-20-09h15m36-UTC and 2026-05-20-09h31m13-UTC, the phase loops were successfully closed after these modifications
• NEB NCAL: operatios performed between 2026-05-20-18h38m05-UTC and 2026-05-20-18h45m18-UTC

Aim:

• Dismount old NNN, NNF, NSN and NSF setups
• Install new NNN and NSN setup
• Recable some channels
• Check position measurements with Survey group
• Check (and if needed correct) the position sensor conventions

Status on arrival (see  old_drawing and pictures NorthBench, EastBench, SouthBench, WestBench):

• NNN:box-2024-10, NNF:2024-13, NSN:box-2024-12, NSF:box2021-07, NEN; 2021-08, NWN: 2021-04
• Noise (sound) levels On North and South setup: Valentin listen to the rotors and determines the FAR rotor (NSF:box2021-07 and NNF:2024-13) are more noisy than near rotors (NNN:box-2024-10 and NSN:box-2024-12) so we keep the Near for next installation. We use the Far rotors as counterweights.
• Survey group (A. Paoli and R. Romboli re-measured the positions of the NEN and NWN rotor (see logbook https://logbook.virgo-gw.eu/virgo/?r=69119). The new results give 3.0444 and 3.0446 meters, about three mm bigger than may 2025 survey.

Old suspended North, East and South setups have been removed (old_drawing , North picture, South picture)

New setups are installed with convention from New_drawing. Cabling have been reshuffled accordingly as well as the DAQ box configuration. Positions sensors are active for all platforms but the motors are not yet ready

Position sensors gain sign have been adjusted to have the direction for all NEB setups with following convention (same as in West end building):

• Lateral, along the x-axis, corresponding to the laser beam (increasing when moving away from the central building)
• Vertical, along the z-axis (positive upward)
• Axial (not lateral as previously stated), along the y-axis, with y = z ^ x

NNN tuning;

• With jigs on NNN plate, adjust the biasis in " virgoData/VirgoOnline/SNEB_dbox_rack.cfg". The mean values (mm) of the position sensors are then (@ 13:53:49 utc with 35 averaging): NNF lateral: 0.0012; NNF Vertical: 0.0004; NNM Axial : 0.0009; NNM Vertical : -0.0013; NNN Lateral : 0.00024; NNN Vertical : -0.00099
• Removing the jigs from NNN, we adjust the plate position untill all sensor measure below 0.06 mm deviation from 0 (see NorthSetupZeroing)

New_drawing and pictures after our work (1, 2, 3, 4, 5, 6, 7)

Yesterday we carried out the survey for measuring the position of the NCal benches @NE. We measured the point on top of the calibrators (Fig.2, Fig.4) for the two benches (east and west side of the tower).

Tab1 reports the result of the survey in VRS coordinates, while the scheme of the survey is shown in the Fig6_SurveyDiagram_Staz01 and Fig7_SurveyDiagram_Staz02.

Fig.1 to 4 report some pictures of the survey carried out, while Fig.5 shows an auxiliary bench placed for the next NCal check survey.

Similar to what was done for the WE building, for the enlargement of the VRS network @NE it was worth confirming the survey done (eLog 69117) with another independent one, carried out with classical tecnique by theodolite and post-processing by compensation software, as we did in the past for all the reference points installed in the Virgo Experimental Buildings (see also VIR-0523AF-13). During last May12-13 we carried out the survey by teodolithe Leica TDA5000 and then the analisys of the raw data by compensationt software StarNet.

Tab1 reports the final result of the compensation obtained showing the VRS coordinates, the standard deviations and the parameters of the relevant error ellipses port the new reference points considered.The resuls obtained are perfectly coherent with those deriving from the laser tracker survey, so that the coordinates of the new points are validated.

Fig.7 reports the whole scheme of the survey carried out, with the graphical indication of the error ellipses, while Fig.1 to 6 shown some pictures of the survey carried out.

Following the installation of the new reference points @NE building (placed as small shelves on the concrete walls of the building and plates on the tower floor), last Apr23 we performed the first survey with the laser tracker Leica AT403.

Similar to what was done for the WE building, we carried out 3 different measures for each of the 4 station in total, at different positions in the building. Each measure has been processed with the Best Fit technique.

Tab1 summarizes the result of the survey in VRS coordinates.

Fig.1 to 6 shown the pictures of the survey carried out and some of the new reference points.

Activities communicated in control room:

• CH laser cooling system installan by Cecilia;
• work on SDB2 LC by Alain;
• Ncal works (Mours);
• INJ: injection chiller checks by INJ team.

While performing these tests, we noticed that the SL crystal temperatures were unusually high.
By checking the trends, we observed that the temperatures started to rise and eventually reached approximately 70°C after the pumping diodes were switched off on 07/05.
This suggests that the temperature controllers are not responding properly in the present configuration.

Under normal operation, both the pumping diodes and the crystals have their temperatures stabilized by the Peltier modules (W signals on the fig attached) in order to maintain the temperatures at their setpoints (SET signals on the fig attached).The hot side of the Peltier modules is itself cooled by the chiller.

Usually, when the pumping diodes and the chiller are switched off, the correction signals go to 100 and everything remains at low temperature.
We had never paid particular attention to this behavior before, but it is already somewhat anomalous, since the controllers should regulate around the setpoints rather than continuously applying maximum corrections.

When we switched off the chiller and the pumping diodes on 08/05, the behavior was different for the crystals: instead of going to 100 as observed for the pumping diodes, the Peltier correction signals for the crystals dropped to 0, and the crystal temperatures started to increase (figure 1)
This behavior is currently not understood. 0 corrections should be the lowest temperature...

The crystals eventually reached approximately 70°C.
When restarting the SL, we will need to assess whether this may have caused any damage and whether the alignment has been affected.

After noticing the issue and we saw that the crystal temperatures were increasing again (figure 2) : without changing anything on the chiller nor the peltier corrections, at 11:30 UTC the temperature of the crystals started to increase again from 40 degrees towards 70 degrees.
So we went to the chiller room to restart the chiller. The Peltier modules only resumed normal behavior once the temperature became close to the setpoint (figure 3).

We found Sa_WI crate off since its power supply was broken (probably due to aging). We replaced it with a spare. Top stage control is now working properly again. 

A selective switch-on test of the Laser system chillers was performed to identify their individual noise contribution to the laser benches.

The test involved the NEOVAN head chiller (Termotec), the main chiller (OMI), and the NEOVAN electronics chiller.

During the test, the AHU used for venting the NI tower remained ON, while the CEB hall and Laser lab AHUs were temporarily switched off and the supply/return air distribution valves together with the outdoor air valves were closed.

The detailed test sequence is reported in the attached file.

The test was completed with all chillers left OFF.

This morning we went in the Eeroom to check the INJ chillers.

- the MAIN CHILLER Omi (which is used for the SL diodes in EEroom, SL crystal in LL and Beam dumps IPC (EIB) + IMC REFL (EIB but not connected) + PMC REFL (LB) + B2 (SIB2) + IPC2 (SIB1 flux blocked)) when switched off was giving the error A05. We changed the filter and switched it on and it was working fine. We switched it off again.

- the NEOVAN HEAD CHILLER Termotek (used for the Neovan head). We switched it on with the circuit closed on itself and this time the pump started (we observed this behaviour also in the past, maybe due to the air which enters while changing the filter)

Yesterday we went to the Laser Lab so Marco could inspect the environment for security reasons following the near miss incident. For that, the EIB was blocked briefly (and Paul took some measuments of the BPC optics distance taking advantage of the window of opportunity) but no other action was taken. 

ITF found in UPGRADING Mode and DOWN State.
All times are UTC.
From 08:46 to 09:26 Melo, Lagabbe and Galimberti went in CEB > Laser Lab;
Activity concluded at 12:06, ITF left in  in UPGRADING Mode and DOWN State.

This morning I installed a new version (v3r3) of the Hameg package in VPM. This new release allows users to set the maximum output current generated by the device and to modify the output voltage using ramps (as requested by TCS group)

In the meantime, I added three new buttons to both the TCS_PAW_NI_PowerSupply and TCS_PAW_NI_PowerSupply processes:

• one to turn the device output on/off,
• one to set the maximum current,
• and one to start a voltage ramp on the output.

To simplify the user experience, I also added a few predefined values in the pop-up windows linked to these buttons in the VPM web interface

The software was tested using the "VPM test" environment and a spare Hameg 8041 device. As soon as possible, I will also perform quick tests in the TCS room.

At 2026-05-14-02h34m43-UTC, no more data from Sa_WI received*

• SUSP_Fb server log report

  • 2026-05-14-02h34m43-UTC>WARNING-[TolmFrameBuilder::ControlMerging] frame: 1462761300.800000000: merging is triggered on timeout (internal 1462761301.161215040 > max 1462761301.160000000)
    2026-05-14-02h34m43-UTC>WARNING-[TfbSubFrame::Fill] GPS: 1462761300.800000000 - Source Sa_WI: 1104/2000 missing packet(s), 0 data break(s) (missing data are at the end of the vector)
    2026-05-14-02h34m44-UTC>INFO...-[TfbSourceManager::Clean] source Sa_WI (62:v07) has stopped -> waiting for data...
    2026-05-14-02h34m44-UTC>INFO...-[TfbSourceManager::Reporting] Sources reporting: / nSrc: 57, missing(1): Sa_WI
    2026-05-14-02h34m44-UTC>INFO...-CfgReachState> Active(Active) Ok

After this event the FbmAlp  server complained about frames delivered too late from all the SUS Automation nodes 

• FbmAlp server log report

  • 2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr: Could not wait longer for frame parts, output 1462761308.0, nSources=31 first:FbsAlp
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_BS start to be missing (isReady)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_NI start to be missing (isReady)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_NE start to be missing (isReady)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_PR start to be missing (isReady)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_WI start to be missing (isReady)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_WE start to be missing (isReady)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_BS start to be missing (out)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_NI start to be missing (out)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_NE start to be missing (out)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_PR start to be missing (out)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_WI start to be missing (out)
    2026-05-14-02h35m02-UTC>WARNING-FdFrMrgr:1462761308.0 frames from SUS_WE start to be missing (out)
    2026-05-14-02h35m03-UTC>INFO...-FdFrMrgrFeed: 1462761308.0 receiving again frames from SUS_NI
    2026-05-14-02h35m03-UTC>WARNING-FdFrMrgrFeed: reject too old frame (1462761308.0) from SUS_NI; last produced was 1462761317.0
    2026-05-14-02h35m03-UTC>INFO...-FdFrMrgrFeed: 1462761308.0 receiving again frames from SUS_WE
    2026-05-14-02h35m03-UTC>WARNING-FdFrMrgrFeed: reject too old frame (1462761308.0) from SUS_WE; last produced was 1462761317.0
    2026-05-14-02h35m03-UTC>INFO...-FdFrMrgrFeed: 1462761308.0 receiving again frames from SUS_BS

After some investigations, restarting the SatServer allows to recover the correct running conditions for the the FbmAlp server, and the SUS Automation nodes

• 2026-05-14-06h32m16-UTC     process:SatServer stopped
  2026-05-14-06h32m20-UTC     process:SatServer started

The Sa_WI data are still missing

ITF found in DOWN, UPGRADING
No commissioning activities communicated to the control room
The shifted was ended after the daily meeting due to the absence of further activities for the day

ITF found in UPGRADING Mode and DOWN State.
All times are UTC. 
06:09 MAINTENACE Mode set.
09:05 Re-engaged SPRB_SBE Tracking Global Control disabled on 6th May 2026.
09:11 Re-engaged SDB2_SBE Tracking Global Control disabled on 5th May 2026.
09:57 SDB2_SBE Firmware udate (Masserot). 
10:07 MAINTENANCE ended, ITF back in UPGRADING Mode.
10:07 Closed PR F7 and MAR loops and guardians.
ITF left in UPGRADING Mode and DOWN State with SDB2_SBE firmware update still ongonig.
No other commissioing activities were communicated to the control room.

ITF found in Upgrading mode and in Down; ISYS off for chiller malfunctioning.

No commissioning activities communicated in control room.

We went to EEroom to investigate the chiller, since we noticed that the CHILLER_PIPE_TE monitor suddenly increased a lot (see Fig. 1). Inside the chiller room, there was an allarm for one of the two chillers (the THERMOTEK chiller), so we filled it in with water (water flow was low) and swapped the filter that seemed a bit dirty, but it didn't restarted after this operation. After some trials we decided to use the spare chiller instead.

However, the OMI chiller wasn't working properly as well (linked to the DMS allarms) but we couldn't identify the problem. So, we decided to switch off everything for safety reasons for the weekend (Neovan amplifier and slave laser pump currents wer set to 0). 

Profiting of the measurements made today, we extracted the plants of the four DoFs needed to design the control filters. The basic idea was to measure the several pole-zero structures in the mechanical plants, to compensate them in the control filters, in order to flatten the mechanical responses and have for all the four degrees of freedom the same open-loop with UGF at 40Hz, controlled by an integrator and a double pole to roll-off the transfer functions (see fig.1) (same as it was done for the BPC controls).

For future reference, the measured and fitted plants for tilt X/Y and shift X/Y are reported in fig.s 2,3,4 and 5, respectively.

The control filter to reduce the excess of noise visible on the TILT X dof spectra has been updated but will be tested next time.