Masatake Ohashi

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DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. The goal of DECIGO is to detect gravitational waves from various kinds of sources mainly between 0.1 Hz and 10 Hz and thus to open a new window of observation for gravitational wave astronomy. DECIGO will consist of three dragfree(More)
Masaki Ando, ∗ Koji Arai, Youichi Aso, Peter Beyersdorf, Kazuhiro Hayama, Yukiyoshi Iida, Nobuyuki Kanda, Seiji Kawamura, Kazuhiro Kondo, Norikatsu Mio, Shinji Miyoki, Shigenori Moriwaki, Shigeo Nagano, Kenji Numata, Shuichi Sato, Kentaro Somiya, Hideyuki Tagoshi, Hirotaka Takahashi, 10 Ryutaro Takahashi, Daisuke Tatsumi, Yoshiki Tsunesada, Zong-Hong Zhu,(More)
Hideyuki Tagoshi, Nobuyuki Kanda, Takahiro Tanaka, Daisuke Tatsumi, Souichi Telada, Masaki Ando, Koji Arai, Akito Araya, Hideki Asada, Mark A. Barton, Masa-Katsu Fujimoto, Mitsuhiro Fukushima, Toshifumi Futamase, Gerhard Heinzel, Gen’ichi Horikoshi, Hideki Ishizuka, Norihiko Kamikubota, Keita Kawabe, Seiji Kawamura, Nobuki Kawashima, Yasufumi Kojima,(More)
A space gravitational-wave antenna, DECIGO (DECI-hertz interferometer Gravitational wave Observatory), will provide fruitful insights into the universe, particularly on the formation mechanism of supermassive black holes, dark energy and the inflation of the universe. In the current pre-conceptual design, DECIGO will be comprising four interferometer units;(More)
Eiichi Hirose, Dan Bajuk, GariLynn Billingsley, Takaaki Kajita, Bob Kestner, Norikatsu Mio, Masatake Ohashi, Bill Reichman, Hiroaki Yamamoto, and Liyuan Zhang Institute for Cosmic Ray Research, the University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8582, Japan Zygo Extreme Precision Optics, 3900 Lakeside Drive, Richmond, California 94806, USA LIGO(More)
The thermal fluctuation of mirror surfaces is the fundamental limitation for interferometric gravitational wave (GW) detectors. Here, we experimentally demonstrate for the first time a reduction in a mirror's thermal fluctuation in a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer Observatory at 17 and 18 K. The detector(More)
We report the reduction of the thermal lensing in cryogenic sapphire mirrors, which is planed to be used in the Large scale Cryogenic Gravitational wave Telescope (LCGT) project. We measured three key parameters of sapphire substrate for thermal lensing at cryogenic temperature. They are optical absorption coefficient, thermal conductivity and temperature(More)
We have applied laser calorimetry to the measurement of optical absorption in monocrystalline sapphire at cryogenic temperatures. Sapphire is a promising candidate for the mirror substrates of the Large-scale Cryogenic Gravitational wave Telescope. The optical absorption coefficients of different sapphire samples at a wavelength of 1.064 μm at 5K were found(More)
We report on the current status of CLIO (Cryogenic Laser Interferometer Observatory), which is a prototype interferometer for LCGT (large scale cryogenic gravitational-wave telescope). LCGT is a Japanese next-generation interferometric gravitational-wave detector featuring the use of cryogenic mirrors and a quiet underground site. The main purpose of CLIO(More)
Current status of TAMA and CLIO detectors in Japan is reported in this article. These two interferometric gravitational-wave detectors are being developed for the large cryogenic gravitational wave telescope (LCGT) which is a future plan for detecting gravitational wave signals at least once per year. TAMA300 is being upgraded to improve the sensitivity in(More)