Vacuum tubes and the cleanroom

Spring 1997: Progress Report

February 18

The welding of the second tube has commenced! The first 15 m have been completed.


Much work has been done within the last weeks to make the central house ready for occupation. The shielding of the tank section by means of plastic sheets has been completed. Next the cleanroom concept will be put into action.

April 23

The welding of the second tube continues to make good progress. 360 m have been completed. The second tube may be finished by June '97.

May 15

490 m of the second tube have been completed.

May 29

The final tube segment has been welded. The second tube is now complete!


The cleanroom facilities for the central station are installed. Preliminary measurements show good performance. Better than class 1000 is reached with one person working in the centre area.

Summer 1997

Inside the Central Building

Tasks to be done: Liners have to be inserted into the tubes at all four ends in order to reduce the stray light. The gate valves have to be mounted. The first tanks have to be moved to the central station.

Tube and Tanks

We are now pumping the east tube and have found and sealed two leaks, but more are to be expected. Five out of the nine tanks to go into the central station are out at Ruthe. They are cleaned and given an air bake at 200°C before they are taken out.

The Liners

The liners have been inserted into the tubes at all four ends. They had to be spot welded to the flanges in order to keep them from moving when rotating or shifting the tube.

September 1997

Three Aerial Views of GEO600:

October 1997: Progress Report

The leak testing of the east tube has been finished. Five leaks have been detected. After sealing them the vacuum meets the requirements. A small leak at a flange now determines the pressure (p(N2) ~ 5•10-9 Torr in the middle of the tube). This will be mended soon. The residual gas is dominated mainly by water. The tube will be encapsulated by rockwool in order to make it possible to heat it up.

Fall 1997

Wrapping the tube

The mild and dry climate in the Fall made it easy to wrap up the tube with layers of rockwool. This served as a preparation for the heating of the tube in January.

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