Sensitivity analysis of a resonant-mass gravitational wave antenna with a parametric transducer

A frequency domain approach is applied to the University of Western Australia’s resonant bar detector to determine its potential sensitivity and calculate the limiting noise sources. To understand its behavior the sensitivity is calculated as a function of various noise components. To minimize seismic noise upconversion, the system is operated in the cold damping regime at the turning point in the antenna frequency versus pump frequency characteristic. For this configuration it is shown that the spectral strain sensitivity of a high-Q antenna with a parametric transducer can exceed 10−21 √Hz with approximately a 20 Hz bandwidth, using existing microwave technology. This corresponds to a strain sensitivity of less than 10−19 for a 1 ms gravitational pulse.