Active measuring device, in particular secondary ion mass spectrometer

Active measuring device (1), in particular secondary ion mass spectrometer, with (a) a vacuum chamber 10), b) a (in the vacuum chamber 10) arranged getter material, c) arranged one (in the vacuum chamber 10) The sample carrier (5) for receiving a sample to be examined (4), d) (to the test 4) facing primary ion source (2) which bombards the sample (4) with a primary ion beam (3), whereby secondary ions (7) (from the sample 4) can be knocked out, e) (a mass spectrometric measuring device (8) to investigate the secondary ions 7) and f) an extraction plate (9) for accelerating the secondary ions (7) in the direction of the measuring device (8), characterized, in that g) the extraction plate (9) at least partially consists of the getter material, the residual gases from the vacuum chamber (10) receives and characterized in the immediate vicinity of the sample (4) the vacuum conditions in the vacuum chamber (10) is improved.