The Gross Ring 'G'

The Gross Ring or 'G' ring laser is a state of the art 4 m x 4 m monolithic ring laser enginered from Zerodur and located in the purpose-built Gross Ring Facility, Bavaria. The result of understanding gained from the C-2 and G-0 lasers, it aims to sense fuluctuation in the earth rotation rate at the level of one billionth the base value.

Like C-2 and G-0, G makes use of the Helim-Neon system at 633nm. A set of 6 high resolution tiltmeters are placed at different locations on top of "G" for mutual control and for the discrimination between rigid body tilts and distortions.

The $19M instrument was funded by Institut fuer Angewandte Geodaesie and Technische Universitaet Muenchen and built by Carl Zeiss Ltd, Oberkochen.

Prof Ulli Schreiber adjusting a ion pump on the G ring laser.