Claims
- 1. 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.
- 2. A multiple-detector system as claimed in claim 1, wherein said charged-particle beams are dispersed to follow different trajectories according to their mass-to-charge ratios, each detector assembly being disposed so as to detect a beam of particles of a particular mass-to-charge ratio.
- 3. A multiple-detector system as claimed in claim 2, wherein said analytical device comprises a charged-particle focusing system having an optical axis, each said charged-particle beam being focused at a point, said points being disposed at various locations on a focal plane, said focal plane substantially coinciding with said first plane along which said detector assembly entrance apertures lie, said detector assemblies being arranged such that the said focal point of a particular charged-particle beam substantially coincides with the said entrance aperture of a particular assembly.
- 4. A multiple-detector system as claimed in claim 3, wherein said focal plane of said charged-particle beams is substantially flat and substantially perpendicular to the direction of said optical axis at an exit of said focussing system.
- 5. A multiple-detector system as claimed in claim 1, wherein said second arms of said detector assemblies are substantially parallel to each other, lengths of said first arms of said detector assemblies within each group progressively increasing by more than a width of a said second arm to enable said detector assemblies within each group to be nested together.
- 6. A multiple-detector system as claimed in claim 5, wherein said second arm of each detector assembly extends substantially at right angles to said first arm.
- 7. A multiple-detector system as claimed in claim 6, wherein two groups of detector assemblies are provided, with said second arms of said detector assemblies of said groups being substantially parallel to each other, but with said second arms of one group of detector assemblies extending in substantially an opposite direction to said second arms of the other group of detector assemblies, to form two back-to-back groups of nested detector assemblies.
- 8. A multiple-detector system as claimed in claim 1, wherein said second arms of each detector assembly extend in various directions so as to be splayed out.
- 9. A multiple-detector system as claimed in claim 1, wherein each said detector assembly is adjustable in position along said first plane so that charged particles may be detected at varying positions which may be at varying distances apart.
- 10. A mass spectrometer having a vacuum housing containing:
- i. a charged-particle source for producing a charged-particle beam;
- ii. a mass analyzer for dispersing said charged-particle beam so that charged particles are dispersed along different trajectories according to mass-to-charge ratio, said dispersed charged-particles being focused by said mass analyzer along a plane, with charged particles of different mass-to-charge ratios being focused at different points along said plane; and
- iii. a multiple-detector system as defined claim 1.
- 11. A charged-particle beam detector assembly comprising:
- a first arm having a member at one end thereof defining an entrance aperture for receiving a charged-particle beam;
- a second arm mounted at an angle to said first arm and having a detector therein; and
- a secondary-emissive element positioned to intersect a said charged-particle beam entering through said entrance aperture, and to emit secondary particles in response to said charged particle beam incident thereon, such that at least some of said secondary particles passing into said second arm are detected by said detector.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9302886 |
Feb 1993 |
GBX |
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of abandoned application Ser. No. 08/194,928 filed Feb. 14, 1994.
US Referenced Citations (8)
Continuations (1)
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Number |
Date |
Country |
Parent |
194928 |
Feb 1994 |
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