[Tomaru, Araki, Ohishi, Shoda]

We measured the position of the mirror inside the vacuum tank using the survaying instrument and the 3D measurement device.

* measurement with the survaying instrument *

Tomaru-san measured the position of the mirror using the survaying instrument.
We used the two scribe lines on the vacuum chamber, and the positioning pin on the floor to make the x-z plane.
Then, we saw where the mirror is relative to that plane using the scribe lines at the center of the RM at HR side.

The result is the mirror was 2mm off to -y direction from the plane we made with the method above.

* measurement with the 3D measurement device *

Araki-san and Ohishi-san measured the position of the mirror relative to the vacuum tank using the 3D measurement device.

Firstly, we measured the external serface of the big flange to decide the the center axis of the vacuum chamber.
After that, we measured the position of the surface of the RM front ring.

The coordinate of the RM front ring surface was (98.7, -3.7, -548.6) mm.
Note that the origin is the center of the vacuum chamber at the surface of the top big flange.

Since the distance between the RM front ring surface to the center of the mirror is 101mm and the distance between the origin and the center of the beam flange is 550mm, the mirror position is (-2.3, -3.7, 1.4) mm off from the center.

Note
When we inject the vertical beam to to the center of the vacuum chamber according to the beam line Terada-san and Fujii-kun made, the line was about 1cm off from the scribe lines on the vacuum chamber.
Hmm...