US 5,471,059 A · Multiple-detector system for detecting charged particles

Abstract

A multiple charged-particle detector system includes a plurality of charged-particle detector assemblies (10-12) which are each made up of a first arm (19-22) and a second arm (24-27) extending at an angle to each other. Charged particles (4-7) enter an aperture (14-18) at the entrance of the first arm (19-22) of each detector assembly (10-12) and strike a dynode (30-33) positioned at the intersection of the two arms causing electrons to be emitted by the dynode (30-33). Some of the electrons pass into the second arms (24-27) of the detector assemblies (10-12) and are detected by a continuous-dynode electron multiplier (35-38). The first arms (19-22) are narrower than the detectors (35-38), and the detector assemblies (10-12) are arranged in such a way that the minimum separation at which charged-particle beams (4-7) can be detected is determined by the widths of the said first arms (19-22) of the detector assemblies (10-12), and not by the widths of the detectors (35-38) themselves.

Claims11

Dependent claims

A multiple-detector system for detecting a plurality of charged-particle beams in an analytical device, said detector system comprising at least one group of charged particle detector assemblies;

wherein each of said detector assemblies comprises a first arm and a second arm extending at an angle to said first arm, said first arm having a member at one end thereof defining an entrance aperture, said second arm having a detector therein;
wherein said detector assemblies are arranged such that said entrance apertures lie substantially on a first plane which intersects the paths of said charged-particle beams, one or more of said detector assemblies being positioned so that a selected charged-particle beam passes through said entrance aperture of a selected detector assembly into said first arm of said selected assembly;
each said detector assembly further comprising a secondary-emissive element positioned to intersect the path of a said charged particle beam which enters said detector assembly through said entrance aperture, said secondary emissive element emitting secondary particles in response to said charged particle beam incident upon it, such that at least some of said secondary particles pass into said second arm of said detector assembly to be detected by said detector.

Dependencies are inferred from the claim text.

Multiple-detector system for detecting charged particles

Life of this patent

Multiple-detector system for detecting charged particles

Life of this patent

Abstract

Claims11