DR. KRISHNA VENKATESWARA

Advanced LIGO, the next generation gravitational wave detector, is getting ready to make first detections of gravitational waves in the next few years. At full performance we expect to be sensitive to differential length changes of less than a fiftieth of an attometer between suspended mirrors at the ends of a 4-km-long michelson interferometer. Key to their operation are the active seismic isolation and suspension systems which suppress ground motion by more than nine orders of magnitude above 10 Hz. In the first half of his talk the speaker will briefly describe the two systems focusing on the active seismic isolation. In the second half he will discuss a new instrument that he has developed at the University of Washington to address a specific concern in low frequency active isolation, namely, the tilt sensitivity of horizontal seismometers. He will describe the absolute rotation sensor he has developed and show some of the ground tilt measurements made with the instrument.