Cryogenic Model of the Gravitational Antenna OGRAN

Abstract

The optoacoustic gravitational-wave antenna (OGRAN) located in the underground laboratory of the Baksan Neutrino Observatory has a limited sensitivity sufficient only to detect gravitational radiation from astronomical objects at a distance of 100 kpc. In order to cover sources in the zone with a radius of up to 15 Mpc, it is proposed to economically upgrade the antenna and cool down the body of the acoustic detector to a temperature of liquid nitrogen of ~78 K [1]. In this case, the spectral density of the Brownian noise of the detector decreases owing to temperature and also owing to the subsequent increase in its acoustic Q factor by one and a half to two orders of magnitude. This paper presents the results of an experiment for testing these ideas on the cryo-OGRAN prototype while preserving the optical detection scheme used for the uncooled antenna.