[miyoki, uchiyama, ohashi]

ETMX suspension tower and mirror alignment was done. The method was as follows.

1) A slit plate, which was made of 1mm thickness AL plate and had about 1cm width in the vertical direction and 2cm length hole in the horizontal direction, was put on the beam axis. The height of this slit hole was about 3cm below the center of the incoming beam because the fixing rod for the slit was little bit short. The distance between the mirror and the slit was about 60cm.

2) The reflected beam relative position to the hole was checked and we found that the reflected beam was shifted slightly towards 4 o'clock position by about 1mm.

3)We adjusted the suspension tower itself by a pushing screw rod to observe an equal scattered light at the right and left sides of the hole.

4)We adjusted the pitch of the test mass by rotating a picomotor to observe an equal scattered light at the top and bottom sides of the hole.

5)We did the same slit method near the GV position that was about 3m away from the test mass. We made an hand-made slit (make a hole (~ 5mm diameter)in a cap for an ICF70 flange) and fixed it on the 1m ruler and inserted it into the beam tube through a small size GV that was situated on the tube side near the GV. No significant reflected light relative shift to the hole was obserbed.

So we could expect ~1[mm]/3000[mm] radian accuracy, which corresponds to 1 m position variation around the BS.