The Ångström Laboratory – A Vibration Free Building on Loose Sand

The Angstrom Laboratory in Uppsala is a centre for research and education in materials science. High resolution microscopy and lithography are essential parts of the work and the scientists wished to have a large flexible area for vibration sensitive equipment. The laboratory is built on top of 50 m loose sand and moraine. Early measurements showed that traffic in adjacent streets caused significant vibrations in the ground. A very stiff concrete slab in two storeys, supported by a pattern of concrete walls, was designed for the vibration sensitive equipment. The slab is founded 5 m below ground level without piling. Strict demands on vibrating equipment ensured low vibration levels. Measurements have showed that the slab fulfils the requirements of BBN curve E, approx. 3 pm/so In a second stage the laboratory will be enlarged to house all research and education in physics and chemistry at Uppsala University. Before the design of the new building took place transfer mobilities were measured in the present building. Thus, demands on vibrating equipment could be determined with a high degree of accuracy, i.e. maximum unbalance for fan wheels, maximum load for overhead cranes etc.