Session H20 - Gravitational Radiation - Experiment.
MIXED session, Sunday morning, April 30
102A, LBCC
Seismic noise will be the dominant source of noise at low frequencies for ground based interferometric gravitational wave detectors, such as LIGO now in the final phase construction. Future interferometers installed at LIGO plan to use at least a double pendulum suspension for the test masses to help filter the seismic noise. We have constructed an apparatus to use as a test bed for double pendulum design. Some of the tests we plan to conduct include: measurements of seismic transfer functions of the double pendulum, by using a high precision vibration shaker; comparison of modal damping to point-to-point damping of the pendulum; measurements of actuator and mechanical cross couplings; and measurements of dynamic ranges of actuators, used to control the position of the double pendulum masses and how to split control between the intermediate mass and lower test mass. All these properties will be studied as a function of mechanical design of the double pendulum. Results will be presented from tests of a single pendulum supported by cantilever springs, which can be controlled in all six degrees of freedom.