Principles of wide bandwidth acoustic detectors and the single-mass DUAL   detector
  We apply the standard theory of the elastic body to obtain a set of equations describing the behavior of an acoustic Gravitational Wave detector, fully taking into account the 3-dimensional properties of the mass, the readout and the signal. We show that the advantages given by a Dual detector made by two nested oscillators can also be obtained by monitoring two different acoustic modes of the same oscillator, thus easing the detector realization. We apply these concepts and by means of an optimization process we derive the main figures of such a single-mass Dual detector designed specifically for the frequency interval 2-5kHz. Finally we calculate the SQL sensitivity of this detector. 
Michele Bonaldi, Massimo Cerdonio, Livia Conti, Paolo Falferi, Paola   Leaci, Stefano Odorizzi, Giovanni A. Prodi, Mario Sar...