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AssigneesShimadzu Corporation, University of York Heslington
InventorsShin Fujita, Mohamed El-Gomati, Torquil Wells
Estimating the term…
Provided is a Schottky emitter having the conical end with a radius of curvature of 2.0 μm on the emission side of an electron beam. Since a radius of curvature is 1 μm or more, a focal length of an electron gun can be longer than in a conventional practice wherein a radius of curvature is in the range of from 0.5 μm to not more than 0.6 μm. The focal length was found to be roughly proportional to the radius of the curvature. Since the angular current intensity (the beam current per unit solid angle) is proportional to square of the electron gun focal length, the former can be improved by an order of magnitude within a practicable increase in the emitter radius. A higher angular current intensity means a larger beam current available from the electron gun and the invention enables the Schottky emitters to be used in applications which require relatively high beam current of microampere regime such as microfocus X-ray tube, electron probe micro-analyzer, and electron beam lithography system.
An electron beam control method comprising an electron beam generating step of emitting electrons from the conical end of an emitter sharpened in the shape of a cone on the emission side of an electron beam by using a Schottky effect under an electric field applied to the conical end to thereby generate an electron beam, the method further comprising:
An electron beam generating apparatus comprising:
An apparatus using electron beam generating means including:
An emitter generating an electron beam in which the conical end of an emitter on the emission side of an electron beam is sharpened in the shape of a cone and is applied with an electric field to thereby emit electrons using a Schottky effect, the emitter having an improvement that a radius of curvature of the conical end is 1 μm or more to control an electron gun focal length.
Dependencies are inferred from the claim text.