Improved sensitivity in a gravitational wave interferometer and implications for LIGO
Sensitivity enhancements in the laser interferometer gravitational wave observatory (LIGO) project's 40 m interferometer have been achieved through two major instrumental improvements. Improved vibration isolation has reduced the noise due to ground motion. New test masses with less mechanical dissipation were installed to lower the thermal noise associated with mirror vibrations. The minimum interferometer noise (square root of the spectral density of apparent differential displacement) reached 3 x 10^(-19) m/Hz^(1/2) near 450 Hz.
© 1996 Elsevier Science B.V. Received 22 January 1996; revised manuscript received 2 May 1996; accepted for publication 3 May 1996. Communicated by P.R. Holland. We thank the entire LEO team for their help and support in this work, including Barry Barish, Albert Lazzarini, and Gary Sanders for suggestions concerning the manuscript. This work is supported by the National Science Foundation under Cooperative Agreement PHY-9210038.