Session H20 - Gravitational Radiation - Experiment.
MIXED session, Sunday morning, April 30
102A, LBCC
This study investigates the influence on the low frequency thermal spectrum of selective cooling of a number of normal modes in a mirror at room temperature. The aim of this study is the cooling of the mirrors for the measure of distances between masses in gravitational interferometers. The interest of this problem is that many systems are characterized by a typical f^-\gamma spectral tail at low frequency. The model used shows an interesting threshold type behaviour. When bi-stabe or multi-stable potentials are considered, a 1/f low frequency tail naturally appears. Both analytical and numerical methods have been used. The results show that no reduction of the power spectral density is appreciable outside the resonances of the system while an external force is introduced in order to produce in-resonance damping.