New Toplogies for the Einstein GW Telescope

In Europe a broad collaboration, including the GEO and Virgo groups, is starting a design study for a third generation gravitational-wave detector called 'Einstein Telescope' (ET) [1], [2]. The challenging goal of this project is to build an instrument providing a sensitivity about a hundred times better than the first generation detectors and to shift the lower end of the observational window to frequencies of ~ 1Hz.

In order to reach these ambitious goals, third-generation detectors will very likely be located deep underground. First of all, this can significantly reduce seismic noise and gravity gradient noise. Secondly, going underground might provide a relative easy realisation of (very tall) low frequency suspensions. Regardless of the details of the implementation, it is clear that a new infrastructure will allow us to design interferometers which are completely different from the Michelson-type (L-shaped) that characterises present laser interferometric detectors. Hence the interferometer geometry and topology become an important area of research and in fact the ET design study emphasises the option for an instrument based on a new topology.

[ET configurations]

Our group has a leading role in the research and development towards ET. We currently focus on the evaluation of potential geometries, topologies and configurations in the context of a third generation underground detector. Our studies take following aspects into account:

[Einstein Telescope]

The ET study is expected to start in February 2008. First goals of our work are: