List to be improved from TAMA SAS experiments
o Inverted Pendulum
- Cabling problem: Mechanical loss of the inverted pendulum is dominated by that of the cabling.
- Due to the loss, the IPs are over-damped and are spoiled its performance less than 1 Hz region.
o Active damping for vertical motions
- Because vertical sensors are no good with signal-to-noise ratio, any vertical active damping controls are not available.
o Local sensors
- Both of LVDT and Accerelometer (ACC) have larger noise levels than these of designed.
- Cabling tests including vacuum one are necessary for LCGT.
o Initial alignemnts
- Most of pico-motor actuators are not operated properly.
- (Need an actuator list of TAMA SAS with operation check)
- Mechanical clearances and the related actuation ranges should be consistent.
- Coil actuator for vertical position adjustment is not available.
o Magnet damping
- Intermidiate mass of the double pendulum part is over damped.
- Mechanical Q values should be less than several hundred, even if active damping controls are applied.
o Design Policy
- As typical seismic spectrum the worst one should be adopted.