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.

One of the gallows with a gate valve in front of the tube.
The gallery.
Details of the ventilation system to be installed.

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.

One of the CF40 flanges welded to the tube in order to bear a quad.
A look at the tube in the trench. You can see the suspension of the tube and the light at the end
of the tunnel.
A closer look at one of the many welds of the tube.
The tanks have a height of 2 m and a diameter of 1 m.
On the left-hand side you see one of the tanks and on the right our "grill". This is a heatable container for the airbake of the tanks. (In order to obtain an idea of it's huge dimensions compare it with the person (Arne) in front of it.)

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.

The wrapped up liners in the central building.
Insertion of a liner into the tube.
The inserted liners.
A look into the liner. Liners and baffles work very well: The tube is pitch dark.

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.

The trench has been uncovered; the curved pieces of corrugated iron lie on the right-hand side. The bales of rockwool have been distributed along the trench.
Wrapping the tubes is no easy work. You have to protect yourself against the inhaling of small particles of rockwool. Here you see Jochen disguised up to his nose and eyes.
A look into the trench: The tube has been partly wrapped up.
Michael passes a layer of rockwool down in the trench where Andy (at the back) and Jochen fix it around the tube.
Go to Editor View