To measure the losses in the chain containing the EOMs, the Faraday and the IPC1 on EIB, the power was measured with a calorimeter, preceded by a f=-50mm devergent lens (newport KBC043)

• Before the EOMs, the measured power was 32.6 W at 12:58:30 UTC.
• After the EIB_M5 mirror, the power was 24.0 W at 14:01:00 UTC

We tried to measure the power without the divergent lens,

• Before the EOMs, P=42.1 W at 14:13:50 UTC
• After EIB_M5, P=30.5 W at 13:02:45 UTC

In every measurements, the output voltage of the PMC_TRA photodiode was stable around 0.53 V. The BPL was closed. It appears that the presence of the lens changes the measurement by 25%, probably due to an absorption or an uncoaded surface or the variation of the beam size on the calorimeter. So we decided to use another lens f=-30mm. 

• Before the EOMs: P= 42.8 W at ???
• After EIB_M5 P=30.1 W at 14:31:40 UTC

The estimated losses of the whole chain is 30%.

We recentered the beam on the BPL quadrant, with the PMC cavity locked, we closed and open the BPL loop, so the piezos are roughly at the position that send the beam into the EOM. Then we move the QN quadrant vertically until the Y signal is cancelled, and the QF until TX signal is cancelled. Then all the setpoints of the BPL are set to 0 urad and 0 um.

After that,we tried to rotate IPC1 while measuring the power after EIB_M5 in order to maximize the measured power. We managed to reach a power of 34.6 W, which corresponds to a 20% loss. Then we changed the horizontal shift setpoint (X_SET signal) in order to maximize the power measured by the calorimeter. By seting X_SET to -200 um, we reaached a 35.6 W power. Which correspond to a 16 % power loss. The others degrees of freedom remains untouched. 

Below the list of the activities communicated in control room:

- INJ: EOM contamination test;

Air Conditioning
from 12:40UTC to 15:40UTC I set the injection area air conditioning system in "Portata Nominale" to allow the work on EOM.

SBE
recovery of SWEB vertical correction with F1 step motors from 7:30UTC to 7:40UTC.

ITF found in DOWN State and UPGRADING Mode.

Below the list of the ativities commuincated in control room:

• cleaning operation of the experimental areas as part of the planned maintenance;
• check of the door of the Laser LAb (Lagabbe and External firm);
• WI baffle checks (69265)

ITF found in DOWN State and UPGRADING Mode.
All times are UTC.
Below the list of activities communicated to the Control Room:
08:10 - 08:56 Menzione, Gherardini, Gargiulo access in the WI Tower (#69262, #69263).
09:00 INJ AHU set to Portata Nominale under request of INJ team (operator).
13:36 Spinicelli and Nocera did measurements in INJ Lab.
14:53 INJ AHU set back to Portata Ridotta (operator).

Activity concluded at 08:56 UTC.

Fabio, Nicola and Julien are entering WI Tower.

For the tests of  the 50Hz harmonics subtraction using ACL, the following channels received by the INJ_rptc

• the ENV_CEB_ELECTRIC channel acquired at 10KHz 
• the PSTAB_PDa_AC_MONIT channel acquired at 20KHz
• the PSTAB_PDa_DC channel acquired at 10KHz

have been transmitted to one of the Test rtpcs , ie rtpc17, by the INJ_Tpro server .

On the rtpc17, a Acl server called Acl17_INJ has been setup to readout these channels

Operations performed between 2026-06-22-07h07m48-UTC and 2026-06-22-07h15m04-UTC

ITF found in DOWN, UPGRADING

Activities and informations reported to the control room:

Cleaning of NI/WI towers and new baffle areas with nitrogen "top gun" and isopropyl alcohol (Menzione, Zaza)
ASC_DIFFp_T{X,Y} addition for RL control test (#69259 Masserot, Viret)

The ASC_Acl server configuration has been updated to transmit at 200Hz the ASC_DIFFp_T{X,Y} channels to the rtpc26 where some tests of the RL control are running:

• lines 1112 to 1118 related to the " Tolm packets to RL control running on rtpc26" part 

operations peformed between 2026-06-19-12h19m22-UTC and 2026-06-19-12h57m46-UTC

We enter also in NI tower

Today we enter the WI tower to clean it with nitrogen top gun

*** Mechanical Transfer Function Measurement of the WI Instrumented Baffle *** 

Today, mechanical transfer function measurements of the WI instrumented baffle were carried out following the same procedure adopted for the WI instrumented baffle. The measurement configurations are shown in Figure 1.
As in the NI measurement campaign, the triaxial accelerometer was mounted on the instrumented baffle through a custom adapter. The final orientation of the sensor exhibited a slight misalignment with respect to the nominal vertical and horizontal directions. The resulting sensor orientations for the WI measurements were:

• Top position: x-axis aligned with the cable direction, y-axis aligned with the adapter axis.
• Bottom position: x-axis aligned with the cable direction, z-axis approximately aligned with the adapter axis.

Figure 2,3,4: measurement configurations with the accelerometer mounted in the upper position of the instrumented baffle and the reference accelerometer positions. 

Figure 5,6,7: measurement configurations with the accelerometer mounted in the lower position of the instrumented baffle and the reference accelerometer positions. 

The analysis of the acquired data will follow.

The list of the acquisitions, together with the corresponding file names, is attached.

ITF found in DOWN, UPGRADING

Activities and informations reported to the control room:

Mechanical Transfer Function Measurement of the WI Instrumented Baffle (IFAE group, Fiori, Spinicelli) with the assistance of Gargiulo, Gherardini and Menzione
Measurement of the EOM power losses (#69252 De Rossi, Gosselin, Lagabbe, Spinicelli)
North arm still closed to vehicles as opposed to what previously communicated

We put a beam dumper after the M8 mirror on EIB to prevent the laser from going to the towers.

We suspected that the 3rd EOM has some power losses. To see whether or not this EOM transmits the power correctly, the EOM was removed from EIB and its transmission was measured with a 1 W laser. The measured losses were about 1%, but the observed power oscillations are about 1% too, so it is not clear whether or not there are losses due to the EOM. It has also been found that the EOM scatters some light as seen in the photos.

To measure the losses of the EOMs, the laser power was measured before the EOMs, after the second EOM and after the third one. All power measurements were done with Ophir calorimeter with an average over 10 s. The beam is always align using the BPL. The photodiode PMC_TRA was monitored for reference.

• When measuring the power before the EOMs, 2 mirrors HR Thorlabs NB1K14 (R>99.9 pol s @1064) and divergent lens were added between the optical path and the calorimeter. Measured power: 32.1 W, on 17 June 16:04 UTC, (PMC_TRA = 0.528 V)
• After the second EOM, 1 thorlabs mirror and the lens were added. Measured power: 31.3 W 17 June 15:53 UTC (PMC_TRA = 0.527 V)
  • Losses:  2.5-3%
• After the third EOM, 1 thorlabs mirror and the lens were added. Measured power: 29.93 W 18 June 07.38 UTC (PMC_TRA = 0.52 V), 30.08 W 18 June 07.57 UTC (PMC_TRA = 0.525 V), 30.34 W on 18 June 08.01:34 UTC (PMC_TRA = 0.53 V)
  • Losses:  5.5-6%

We replaced the third EOM with the spare that was in optics lab.

• After the third EOM, 1 thorlabs mirror and the lens were added. Measured power: 30.75 W 18 June 08:43:19 UTC (PMC_TRA = 0.53 V),  30.74 W on 18 June 08:45:00 UTC (PMC_TRA = 0.53 V)
  • Losses:  4.2%

The losses measured with the spare EOM were a bit lower than the old one, we don't know if this is because the cristal was a bit dusty, or if it is a alignment problem.

After doing the measurements, we realized that the spare EOM cage was not tighten correcly, so we tighten all screws, which may affect the alignment of the EOM and so its losses.

The 22.304 MHz signal that is sent to the third EOM was switched on again. The beam after the EOMs has to be realigned with the mode matching telescope.

As requested by the IFAE team, we entered the central building to turn off both slds in the WI tower.

The attached figure shows the sources' positions.

*** Mechanical Transfer Function Measurement of the NI Instrumented Baffle ***

Today, mechanical transfer function measurements of the NI instrumented baffle were performed. The instrumentation, data acquisition system and excitation setup are described in the previous logbook entry [elog 69222]. The instrumented baffle was excited using the (big) shaker installed on the tower base.

The single reference monoaxial accelerometer was sequentially moved among three different locations within the NI tower, shown in Figure 1 (first pdf file):

• R1: horizontal mounting position below the instrumented baffle;
• R2: vertical mounting position located close to the instrumented baffle;
• R3: horizontal mounting position on the vacuum vessel.

Figure 1 shows the three reference locations together with close-up views of the sensor installation. 

The triaxial accelerometer was mounted directly on the instrumented baffle and moved between two different locations during the measurement campaign. The upper and lower accelerometer positions are shown in Figure 2 (second pdf file).
The sensor was attached using a custom adapter manufactured by the IFAE group. Due to the threaded mounting, the final orientation of the sensing axes was determined by the thread engagement and could not be precisely aligned with the nominal vertical-horizontal reference frame.

The resulting sensor orientations were:

• Top position: x-axis aligned with the cable direction, z-axis aligned with the adapter axis.
• Bottom position: x-axis aligned with the cable direction, y-axis aligned with the adapter axis.

Figure 3,4,5: Measurement configurations with the accelerometer mounted in the upper position of the instrumented baffle. The three figures show the corresponding locations of the reference accelerometer: R1,R2,R3, respectively.

Figure 6, 7, 8 : Measurement configurations with the accelerometer mounted in the lower position of the instrumented baffle. The three figures show the corresponding locations of the reference accelerometer: R1, R2, R3, respectively

The measurements were performed before the installation of the flange baffle, in order to access the instrumented baffle structure directly.

The analysis of the acquired data will follow.

R. Cavalieri, F. Nocera

while inspecting the NE Ring Heater Power Supply (entry 69238)  we noticed that the PCal Laser Power Supply (?) unit (see picture) has an ominously noisy fan.

I would suggest to have it checked/swapped with a spare.