KAGRA

from Wikipedia, the free encyclopedia

KAGRA ( Kamioka Gravitational Wave Detector , also Japanese か ぐ ら ) is a Japanese gravitational wave detector that is located in the Kamioka mine in the former Kamioka (now Hida ) of Gifu Prefecture in Japan . It is operated by the Institute for Cosmic Ray Research (ICRR) at the University of Tokyo . The previous project name was Large-scale Cryogenic Gravitational wave Telescope (LCGT). Construction began in 2010 and was completed in 2017. The detector has been tested since spring 2018, and the first observation run began in February 2020.

The detector is based on the principle of a Fabry-Pérot interferometer . He has an arm length of 3 km. The laser used has a power of around 80 W. The mirrors are made of sapphire and are cooled down to 20 K in order to reduce thermal noise. The lower detection limit of the detector is at amplitudes of 3 · 10 −24 at a frequency of 100 Hz.

particularities

This detector is the only interferometric gravitational wave detector to date that works with cryogenics . In preparation, a 100 m long interferometer with cryogenics was tested as part of the CLIO project ( Cryogenic Laser Interferometer Observatory ). This forerunner project was successfully completed in 2006. Unlike the other detectors, sapphire mirrors were used because of the cooling because they have better optical properties at low temperatures. Another special feature of the detector is its subterranean position, which means that seismic noise can be kept as low as possible. The Kamioka Mine was chosen because it is one of the most seismically quiet places in Japan.

swell

Individual evidence

  1. ↑ T. Akutsu et al. : Construction of KAGRA: an underground gravitational-wave observatory . In: Prog. Theor. Exp. Phys. 2018, p. 013F01 , doi : 10.1093 / ptep / ptx180 .
  2. ↑ Davide Castelvecchi: Japan's pioneering detector set to join hunt for gravitational waves . In: Nature . tape 565 , 2019, pp. 9 , doi : 10.1038 / d41586-018-07867-z ( nature.com ).
  3. ↑ KAGRA Gravitational-wave Telescope Starts Observation. KAGRA Observatory, February 25, 2020, accessed on February 25, 2020 .