EDDY-CURRENT DAMPING OF HIGH-Q PENDULUMS IN GRAVITATIONAL-WAVE DETECTION EXPERIMENTS

The test masses of a large interferometric gravity wave detector (VIRG O project) will be controlled by actuators consisting of magnets attac hed to the masses and solenoids attached to an auxilliary and potentia lly electrically conductive reference mass. A brief analytic model of the damping produced by the eddy currents induced by the magnets' moti on relative to the reference mass is presented. The results of a serie s of experimental tests to verify this model are also given. They demo nstrate that a conducting reference mass should not degrade the Q of t he pendulum sufficiently to affect the sensitivity of the VIRGO detect or. (C) 1998 American Institute of Physics. [S0034-6748(98)03007-X].