[Eleonora, Manuel, Tatsumi, Raffaele]

We took two viewport shelves from NM1 tank and installed them at the North-West and South-West viewports of PR tank.

We placed a laser and a mirror on the North-West viewport shelf and placed a PSD on the South-West viewport shelf.

We tried to send the laser to the front surface of the mirror. Since the mirror suspension is not centered on the stack, there is not enough space to get the reflected beam on the other viewport.  We decided to send the laser on the back surface of the mirror.

We placed to mirrors as show in the picture. Part of the laser is transmitted and goes to hit the tank wall. Part of the transmitted beam is reflected by the second surface and goes to hit the tank wall on the other side.

We closed the tank.

Then we checked the T, X and Y signals of the PSD using an oscilloscope. The optical lever looks working fine. We remark that the X signal (Yaw motion) is strongly dominated by an oscillation at about 1Hz.