Unprecedented levels of seismic isolation are required to achieve the sensitivity necessary to observe gravitational waves in Advanced LIGO. This award supports the development of instruments and techniques to ammeliorate the effect of seismic vibrations on the overall detector performance. The active seismic isolation stages in Advanced LIGO employ seismometers located on the ground and on the isolated platform to measure and subtract ground motion. However, horizontal seismometers cannot distinguish between ground tilt and horizontal acceleration. Tilt-horizontal coupling complicates the feedback and is a significant noise source for seismic isolation in Advanced LIGO. This award supports the development of a high precision inertial sensor to measure horizontal tilt independently from horizontal acceleration. Removing tilt and tilt noise from the horizontal seismometer channels will improve Advanced LIGO seismic isolation.
The tiltmeters we are developing are unique and not commercially available. These instruments may have applications in other fields of science such as in geophysics, well beyond gravitational wave research. This award not only supports the development of a device for Advanced LIGO but it also serves to maintain and strengthen synergistic activities of our table-top gravity group with the gravitational wave detection community. The technical developments and experiments are carried out by a university-based research group, which has a strong tradition of educating undergraduate students, graduate students and postdocs in building precision mechanical instruments. With the expertise gained through projects, such as developing a one-of-a-kind tiltmeter, our students fill positions in academia as well as highly skilled positions in industry. Our group is strongly committed to outreach on all levels.
