Members: Eleonora, Manuel, Tatsumi, Yuefan

Some preliminary work has been done to prepare the installation of the oprical lever for controlling filter cavity input mirror (already suspended in NM2)

Mirror check      

The suspendend mirror  has been checked after the earthquakes of the past weekend. No damages have been found.

Coil drivers connection 

The four coil drivers to be used to move the mirror have been connected.

PSD electronics

The electronics necessary to power and to read signals from the two PSD need for the optical lever has been assembled and checked. (See picture attached)

PSD calibration

PSD have been calibrated by shining a laser to them and looking at the change in the output voltage when gradually varying their position in x and y direction.

In the plot attached the voltage value has been normalized using the total output value (SUM). The (normalized) calibration value found is  about 6.6*10^-3 m/V

Laser check

We checked the dimension and the beam power of the  laser to be use for the optical lever. Dimensions of the beam (measured with a beam profile after 30 cm) are about 1.1 mm. The recommended dimensions for the PSD are beetween 0.2 and 7 mm.

We also checked the PSD output as a function of the laser power and we observed that the  signal saturates for a power higher than 0.15 mW.