| 摘要 |
A small radii mass spectrometer that utilizes high energy density permanent magnets of greater than 10E7 GOe for focusing an ion trajectory. The ion optical path employs focusing of the parallel component of the beam emitted by the source such that the momentum selected beam is focused in 90 DEG geometry at or near the exit pole face. The width of the beam at the focal point is independent of the size of the beam exiting the ion source in first order but has a second order aberration term dependent on the source width and radius of curvature. The dominant terms in determining the collected beam width are the angular divergence of the source (which can be reduced by defining slit) and the energy spread of the ion beam. A second magnet may be used in tandem with the first magnet to cancel the second order aberration term and reduces the background created by ions scattering with residual gas molecules in the vacuum chamber. A slit between the tandem magnets is used in concert with a final defining slit to increase the resolution. Standard source technology including sample inlet through gas chromatography may be used for the ion source and the separated ion beam output may be used for mass spectrometry, ion implantation, leak detection, nuclear reaction phenomenology, and any other applications requiring a separated mass beam.
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