Developments of Cryogenic Laser Interferometer Observatory (CLIO) and Local Suspension Point Interferometer (LSPI) in Kamioka

Abstract

614平成23年 3 月 9 日 第58回応用物理学関係連合講演会で発表  1 東京大学宇宙線研究所（〒277 8582 千葉県柏市柏の葉 5 1 5）  2 産業技術総合研究所（〒305 8561 茨城県つくば市東 1 1 1）  3 東京大学宇宙線研究所神岡宇宙素粒子研究施設（〒506 1205 岐阜県飛騨市神岡町東茂住456） Fig. 1 The Cryogenic Laser Interferometer Observatory (CLIO) is a laser interferometric gravitational wave (GW) detector. CLIO is a prototype of the Large-Scale Cryogenic Gravitational Wave Telescope (LCGT). Both CLIO and LCGT use the same cryogenic mirror technique as well as the underground site of Kamioka mine. The cryogenic mirror technique is a method to reduce thermal noises that are fundamental in GW detectors. The most important purpose of CLIO is to demonstrate sensitivity improvement by using the cryogenic mirror technique. During the operation of CLIO with cryogenic mirrors, several unique behaviors in the interferometer systems were found. One of the serious issues that we found was low eŠectiveness of the magnet damping system for a mirror suspension system at cryogenic temperatures. Thus, we have developed a new damping system, the Local Suspension Point Interferometer (LSPI). In this article, we give a brief introduction to CLIO and recent results of the LSPI experiments in CLIO.