(ed.). Gravitational waves (IOP, 2001)(422s).

94 Resonant detectors for gravitational waves and their bandwidthFigure 8.1. Spectral amplitudes ˜h present and planned (see equations (8.13) and (8.11))using the parameters given in table 8.1 versus frequency (Hz). The presently operatingdetectors have bandwidth ∼1 Hz. The bandwidth will be much larger in the near futurewith improved transducers.Table 8.1. Bandwith and sensitivity for presently operating detectors and for futuredetectors with improved transducers.T △ f(˜h min )(K) Ɣ Q (Hz) √ 1Hz0.1 10 −6 8.5 × 10 5 1.1 5.3 × 10 −220.1 10 −11 4.2 × 10 6 70 2.3 × 10 −22The present detector bandwidths are of the order of 0.5 Hz, but it is expected thatthe bandwidths will become of the order of 50 Hz, by improving the amplifiernoise temperature T n , the coupling parameter β and the quality factor Q.In figure 8.1 we show the spectral amplitude ˜h for the present aluminiumresonant detectors with mass M = 2270 kg operating at temperature T = 0.1 Kand the target ˜h planned to be reached with improved transducers. The parametersused for calculating the spectral amplitudes are given in table 8.1.