Buildings and trenches finished; Installation of vacuum tube beginning
K. Danzmann
University of Hannover

GEO600 is a laser interferometric gravitational wave detector with 600 m long arms being built in the small town of Ruthe, near Hannover, Germany. It is designed and constructed by a British-German Collaboration comprising the research groups from University of Glasgow (Jim Hough), University of Cardiff and Albert-Einstein-Institut (Bernard Schutz), and University of Hannover and Max-Planck-Institut für Quantenoptik (Karsten Danzmann).

The objective is to use advanced technology right from the beginning and to achieve a sensitivity not too far from first generation LIGO and VIRGO. GEO600 will serve as a testbed for second generation detector concepts and possibly take part in the first round of coincidence observations. GEO600 is a somewhat smaller instrument, but is meant to be very flexible and can be built on a short time-scale. Because the detector is not designed to be extensible in length, the total capital cost of the project can be kept to about 7 M$.

Groundbreaking for GEO600 was in September 1995. Due to an unusually cold winter, construction was delayed for several month. But this month the buildings and the trench for the submerged vacuum tube were finished. The vacuum tube has a diameter of 60 cm and is of an unusual but cost-effective design that has been proposed by Roger Bennett from Rutherford Appleton Laboratory. We are using a wall thickness of only 0.8 mm and the tube is stiffened by a continuous corrugation of about 1 inch amplitude that runs along the whole length of the tube. No bellows are thus required to take up the thermal expansion. The tube is suspended inside the trench by a wire pendulum from rollers running along a rail. The vacuum tube is manufactured in 4 m long segments that are delivered to the site, welded to the rest of the tube in the eastern end building and then pushed into the trench. Welding and installation of the tube on the site are beginning in the first week of September.

More information about GEO600 can found at our web site

Jorge Pullin
Sun Sep 1 16:45:26 EDT 1996