Abstract: There is provided a method and an apparatus for isolating mechanical vibrations reacting to beam metrology tools. The apparatus includes an outer structure for supporting a metrology instrument, and a chuck for holding a specimen with respect to the metrology instrument in an intended defined position for performing measurements on the specimen by the metrology instrument. The apparatus also includes at least one active vibration isolator means coupled to the chuck for compensating relative movement between the specimen and the metrology instrument. A method is also provided that includes detecting change of position of the specimen in response to mechanical vibrations, and effectuating an active modification of the position of the chuck in response to the detection for counteracting a relative displacement between the specimen and the metrology instrument.