Prof. Giles Hammond

The 40kg core optic mirror suspensions used in the aLIGO detectors have enabled the low frequency seismic and suspension noise to be suppressed to a level of 10-19m/ÖHz at 10Hz. This is via the use of multiple stage pendulum suspensions and a final stage of fused silica. The suspensions have extremely high quality factor, around 2 billion for the first violin mode, which highlights the low level of thermal noise. In this talk I will describe how the aLIGO quad pendulums provide such remarkable performance and some of the unique properties of fused silica as a suspension construction material. I will also discuss some opportunities for LIGO India and the work ongoing at RRCAT.