Baffle arrangement for LCGT Previous consideration 　Baffles are placed at calculated reflection points. But! 　Reflection points are separated in the asymmetrical configuration for LCGT. R. Takahashi, June 30, 2006

Effective baffle number Arm length L Radius of pipe R Height of baffle h Pitch of baffle d

Parameters Revised points Arm length 3000m Pipe diameter 1000mm Mirror diameter 250mm Radius of curvature 4500m Height of baffle 50mm Pitch of baffle 11m Distance of mirror 600mm Offset of mirror 340mm Seismic motion @30Hz 10-11m/Hz1/2 Effective baffle number 27 Revised points 2 arms ➞ x1.4 w0 23mm ➞ 33mm Sensitivity @30Hz 1x10-23 ➞ 2x10-23 [/Hz1/2] (6x10-20[m/Hz1/2])

Estimated noise cf. Sensitivity of LCGT 6x10-20 m/Hz1/2 Pipe diameter 1.0m 1.2m Number of baffle 27 22 Direct coupling [10-21m/Hz1/2] 0.2 - Pipe scattering 4.9 1.0 3.1 0.6 Safety margin 12 60 19 100 (COST: \70M ➞ \238M)