  The construction and the vibrational performance of a low vibration
laboratory for microscopy applications comprising a 100 ton floating foundation
supported by passive pneumatic isolators (air springs), which rest themselves
on a 200 ton solid base plate is discussed. The optimization of the air spring
system lead to a vibration level on the floating floor below that induced by an
acceleration of 10 ng for most frequencies. Additional acoustic and
electromagnetic isolation is accomplished by a room-in-room concept.
