The University of Western Australia?s Resonant-bar Gravitational Wave Experiment

Abstract

The cryogenic resonant-mass gravitational radiation antenna at the University of Western Australia (UWA) has obtained a noise temperature of <2 mK using a zero order predictor filter. This corresponds to aIms burst strain sensitivity of 7x 10-19 . The antenna has been in continuous operation since August 1993. The antenna operates at about 5 K and consists of a 1· 5 tonne niobium bar with a 710 Hz fundamental frequency, and a closely tuned secondary mass of 0·45 kg effective mass. The vibrational state of the secondary mass is continuously monitored by a 9·5 GHz superconducting parametric transducer. This paper presents the current design and operation of the detector. From a two-mode model we show how we calibrate, characterise and theoretically determine the sensitivity of our detector. Experimental results confirm the theory.