Baseline Interferometers under Construction

The major planned ground-based interferometers are LIGO, VIRGO, GE0600, TAMA, and AIGO. The sensitivity is shown in the top part of Fig. 6. 

The VIRGO project is a French/Italian collaboration using a 3-km arm length detector close to Pisa, Italy. The Michelson interferometer is equipped with Fabry-Perot cavities. The seismic attenuation system is the combination of an inverted pendulum for preisolation and a five-stage pendulum cascade (superattemator). The arrangement allows for an extension of the sensitivity band down to 4 Hz. The interferometer is actually under constmction and is expected to be operative in 2002. 

The TAMA300 project is a Japanese interferometer with 300-m arm length and Fabry-Perot cavities. The detector began operating in 1999 with a sensitivity of 3 X 10 and has recently set an upper limit of 0.59 hr on the rate of coalescence of close binary neutron stars. 

FIGURE 6 Strain noise sensitivity of the interferometric detectors. Top figure ground-based interferometers VIRGO (solid line), LIGO (dashed line), GE0600 (dotted line), and TAMA (dot-dash line). Bottom figure the space interferometer LISA. 

The first stage of the AIGO detector in Australia was completed in 2000. 

---