Today, after the venting of the SDB1 tower was completed, the VAC team opened the SDB1 tower around 08h30 utc and installed the nitrogen setup blowing on the cryotrap window.

Meanwhile we performed some actions on the SDB1 rack:
➢ disconnect the SDB1 waveplate that we are going to remove from Agilis driver AG_UC8, channel 3 axis 2.
➢ Replug the cable on the picomotor driver 8742 SN 10592, channel 4 (B5_M1_TX)

The VPM main configuration has been updated accordingly to remove the button related the driving of the Pre-Faraday waveplate under SDB1_Rot process.

Noticing that the height of SDB2 bench had changed during the night, we went inside the DET lab to remove some mass from the bench and we were able to recover the right height, and to close the angular and position loops. However we lost the DAQ box LeftUp shorhtly after. So we had to reopen the control loops.

Paolo recovered the SDB1 bench position and the SDB1 local control could be closed.

We adjust the gain of the OMC Peltier to 20 (instead of 50) in order to be able to control the OMC in air. OMC temperature stabilization closed at 9h33 utc.

SDB2 control restored at 10h14 utc.

Antonio switch off the air flux inside the tower at 10h20 utc.

We take some alignment references with NI single bounce beam:

* SDB1 LC is set to TX = 60 (instead of previous WP at 120) / TY = 20 (instead of previous WP at 60)

* B1p camera is centered, with Pos X = -0.1, Pos Y = +0.15

We open the OMC shutter at 10h42m50 utc. We have 4 mW on the B1s beam. The beam is centered on B1s camera at position X = 0, Y = 0

To be noted that we observe an electronic offset of 31.2 mW on DET_B1p_DC when B1p_PD2 shutter is closed. We read 34 mW when the shutter is opened, which implies a power on B1p beam equal to about 3 mW which is in reasonable agreement with B1s power.

We open B1 PD1 and PD2 photodiodes at 10h52 utc.

We scan the OMC and observe the following modes:

* 0.1 mW on the TEM00

* 0.17 mW on the first order mode

* 0.3 mW on the second order mode

* 0.5 mW on the order 3

* 0.5 mW on the order 4

* 0.21 mW on the order 5

We close the OMC shutter, open the controls. Next step will be to perform the foreseen installation works inside the tower.