Baffle arrangement for LCGT

1
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
2
Effective baffle number
Arm length L Radius of pipe R Height of
baffle h Pitch of baffle d
3
Parameters
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 _at_30Hz 10-11m/Hz1/2 Effective baffle
number 27

• Revised points
• 2 arms ? x1.4
• w0 23mm ? 33mm
• Sensitivity _at_30Hz 1x10-23 ? 2x10-23 /Hz1/2
  (6x10-20m/Hz1/2)

4
Estimated noise
cf. Sensitivity of LCGT 6x10-20 m/Hz1/2
Pipe diameter 1.0m 1.0m 1.2m 1.2m
Number of baffle 0 27 0 22
Direct coupling 10-21m/Hz1/2 0.2 - 0.2 -
Pipe scattering 10-21m/Hz1/2 4.9 1.0 3.1 0.6
Safety margin 12 60 19 100
(COST \70M ? \238M)