MASS SELECTOR

摘要

A mass selector is disclosed for separating particles in a particle beam according to mass. The selector has a pair of first electrodes (12, 14) defining an elongate first path (16) for the passage of a focused particle beam. A pair of second electrodes (24, 26) are spaced from the pair of first electrodes (12, 14) and define an elongate second path (28) for separated particles. The first and second paths (16, 28) are mutually parallel. A first voltage pulse is applied across the first electrodes (12, 14) so that the particles in a portion of the beam which is in the first path (16) are accelerated transversely of their direction of movement along said first path toward said second path. A second voltage pulse is applied across the second electrodes (24, 26) so that particles which have been accelerated by said first voltage pulse and which have entered said second path (28) are decelerated transversely of their direction of movement along said second path.