54 Progress of Theoretical Physics Supplement No. 163, 2006 Experimental Efforts to Detect Gravitational Waves Large Scale Cryogenic Gravitational Wave Telscope

A remarkable design of LCGT was established by experimental efforts to detect gravi-tational waves in Japan including optional alternatives in design detail. The LCGT adopts an advanced technique regarded to be used in the third generation. We can reliably detect gravitational waves by LCGT and still have a chance to firstly detect it. Early in 2004, TAMA,1) LIGO(I) (with three interferometers)2) and GEO3) con-ducted their third collaborative observation with a time scale of two months. How-ever, the ultimate sensitivity attained by these interferometers was not sufficient for the frequent detection of coalescence gravitational wave signals, because of the lo