Some NN geophones have been disconnected and displaced in preparation for the crane maintenance scheduled for Tuesday the 28th.

Some NN geophones and microphones have been disconnected and displaced in preparation for the crane maintenance scheduled for Tuesday the 28th.

In order to measure the optimal gouy phase for the BS sensing I' ve measured the sensing matrix between Sc_BS_MAR_TX_CORR @ 3.1 Hz (for tx) and 3.7Hz (for ty) in the last 200sec of Carm null 1f (having a statistics of 200 days locks since the January 2025) and ASC_B1p_QD1/2_50MHz_H/V_I (in which we have the automatic tuning of the phase to minimize the even modes).

The result is visible in Figure 1, considering (TBC) that QD1 has -45 deg of gouy phase and QD2 45 deg (if this is wrong the fit has to be redone).

Then it comes out that the optimal gouy phase is 78 deg for ty and 16 deg for tx.

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

On-call events -> Air Conditioning

Title: North End Chiller Alarm

Author(s): romboli

Details:

I received three high temperature alarm from North End Building. I did not take immediate action because the readings were not excessively high. When I arrived on site, the DMS showed that the temperature was in normal limit (green flag). I couldn't check remotely because the internet is down since yesterday. At the North End Building the chiller was working properly and the temperature inside the hall seemed right. Then alarms ceased.

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

While inspecting the WI payload we noticed three spots on the AR surface of the mirror. Looking through the CP, we can see two spots in the right lower direction from the center and one is located in the left lower direction from the center. All of them are within a range of 10 cm from the center.

Some remarks: the spots do not look like point absorbers. PAs are usually sub-micrometer scale and these are round cloudy mm-scale spots. A cleaning operation would be very risky and we decided not to touch the mirror, also motivated by the fact that the spots are NOT located in the HR surface of the mirror.

Some pictures will follow when the network is back.

This morning starting from 11:00 LT me, Rossi Fabrizio and INGV people (Greco Filippo, Messina Alfio and Mirabella Luca) mooved the Absolute Quantum Gravimeter from 1500W Fiber Lab to WEB experimental Hall as scheduled (#69223).
The packaging procedures were completed at 12:00 LT. Then, we mooved the boxes up to WEB and we installed it along the south wall of the building (Fig 1). The hardware installation was completed around 13:30 LT.
We left WEB at 13:45 LT and we went back to the building at 14:45 LT.
We encountered some issues with the local interent connection in the morning (not related with the loss of GARR connection reported by IT Service), the problem has been soved by IT department in the afternoon.
We completed the installation at 15:30 LT with the Gravimeter fully operational locally, once the GARR connection will be restored it will be able to be reached from outside EGO.

The Gravimeter, its control unit and the Computer must not be touched, advicing signs have been attached nearby.
 

During the WI payload works we also verified that the PAM system is well aligned with the mirror center. The led of the PAM system on the tower base was swicthed on and Ettore from inside the tower verified that the led beam was reaching the same place it was before. The baffles around the payload were taken as reference for this check. 

In the morning we completed the works concerniing the WI payload installation.

The balance was done and the mirror reuslted misaligned WRT the maiornette, similarly to the NI case, by  non-negligible  values.

TY= +3700 urad ; TX= -500 urad ; Tz= +2000 urad. The OpLev sensing will be reset later on.

The system behaves normally. 

The flange has ebeen closed and the pumping is goin on. Pictures will follow.

Excellent ciollaboration by all the teams involved: VAC, Clean-Operaiton, in-vac-Cabling  

We noticed two spots on the rear face of the mirror. They appeared as the first contact was peeled-off.

Later on Suzanne and Eugenio took some pictures to verify the situation. It has been decided not to touch. Another dedicated entry will follow.

In case someone in the future wants to connect the opening and closing of work permits. The NI tower permit to work has been closed using an independent logbook entry https://logbook.virgo-gw.eu/virgo/?r=69393

While the IMC and the RFC were locked and the BPC was following the IMC, we tried to change the setpoints of the AA control loop. We changed the setpoints of the MCT_{h/v}_SET and {N/F}F_AC{h/v}_SET channels.
While changing the FF_ACv_SET setpoint toward negative values, there were a clear improvement RFC_TRA power, however, the Ioop became unstable because the sensing matrix changed with the setpoint.

The next figure shows the evolution of the IMC_TRA and RFC_TRA while we were changing the diffferent setpoints

After the test, we set back the RF quadrants setpoints to 0, and the setpont the end mirror quadrand to -0.1 vertical and +0.45 horizontal. Then, we tuned the INJ_IMC_SET in order to minimize the coupling with PMC.

Below the list of the activities communicated in control room:

• standard maintenance in the morning with cleaning operation of the experimental areas and CEB + MCB bridge crane maintenance;
• test on the electrical generator of the TB;
• NI payload balancing and first contact peeling;
• PAY WI intehration;
• visual inspection of NCal at WE by Benoit.

Afternoon operations:

NI tower: final cleaning, wafer positioning, flange closing (Francescon, Gargiulo, Menzione)

WI tower: payload integration (Benedetti, Majorana, Menzione, Zaza)