Current status of the CLIO project

Abstract

CLIO (Cryogenic Laser Interferometer Observatory) is a Japanese gravitational wave detector project. One of the main purposes of CLIO is to demonstrate thermal-noise suppression by cooling mirrors for a future Japanese project, LCGT (Large-scale Cryogenic Gravitational Telescope). The CLIO site is in Kamioka mine, as is LCGT. The progress of CLIO between 2005 and 2007 (room- and cryogenic-temperature experiments) is introduced in this article. In a room-temperature experiment, we made efforts to improve the sensitivity. The current best sensitivity at 300 K is about $6\times 10^{-21}/\sqrt{\mathrm{Hz}}$ around 400 Hz. Below 20 Hz, the strain (not displacement) sensitivity is comparable to that of LIGO, although the baselines of CLIO are 40-times shorter (CLIO: 100m, LIGO: 4km). This is because seismic noise is extremely small in Kamioka mine. We operated the interferometer at room temperature for gravitational wave observations. We obtained 86 hours of data. In the cryogenic experiment, it was confirmed that the mirrors were sufficiently cooled (14 K). However, we found that the radiation shield ducts transferred 300K radiation into the cryostat more effectively than we had expected. We observed that noise caused by pure aluminum wires to suspend a mirror was suppressed by cooling the mirror.

8 pages, 9 figures. Amaldi7 proceedings, J. Phys.: Conf. Ser. (accepted)

References in corpus (4)

• Evidence for oscillation of atmospheric neutrinos
• Stable Operation of a 300-m Laser Interferometer with Sufficient Sensitivity to Detect Gravitational-Wave Events within our Galaxy
• Mechanical quality factor of a sapphire fiber at cryogenic temperatures
• Ultra-stable performance of an underground-based laser interferometer observatory for gravitational waves

Cited by in corpus (6)

• Prospects of higher-order Laguerre Gauss modes in future gravitational wave detectors
• Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector
• Gravitational waves, dark energy and inflation
• Thermal-noise-limited underground interferometer CLIO
• Feasibility of measuring the Shapiro time delay over meter-scale distances
• Tests of cryogenic Fabry-Perot cavity with mirrors on different substrates