Detector configuration of KAGRA–the Japanese cryogenic gravitational-wave detector

TLDR

KAGRA is a second‑generation Japanese gravitational‑wave detector whose construction has begun and incorporates the latest advanced technologies. This paper presents KAGRA’s detector configuration, detailing its design, strategy, and parameter downselection. The 3‑km detector is built underground to isolate it from seismic motion, its core optics are cooled to 20 K to suppress thermal noise, and quantum non‑demolition techniques are employed to reduce quantum noise. The authors anticipate that KAGRA will detect space‑time ripples from distant galaxies within the next six to seven years.

Abstract

Construction of the Japanese second-generation gravitational-wave detector KAGRA has been started. In the next 6 \sim 7 years, we will be able to observe the space-time ripple from faraway galaxies. KAGRA is equipped with the latest advanced technologies. The entire 3-km long detector is located in the underground to be isolated from the seismic motion, the core optics are cooled down to 20 K to reduce thermal fluctuations, and quantum non-demolition techniques are used to decrease quantum noise. In this paper, we introduce the detector configuration of KAGRA; its design, strategy, and downselection of parameters.