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AssigneesHitachi High-Technologies Corporation, Hitachi Science Systems, Ltd.
InventorsAkimitsu Okura, Masashi Kimura, Kenichi Hirane, Yoshihiko Nakayama
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Disclosed is an electron beam apparatus and method which can retain the state that minimizes the amount of water content contained at a gap between a high-voltage cable and a high-voltage introduction insulator to thereby prevent creation of high-voltage discharge and current leakage. The apparatus comprises a means for applying a high voltage to an acceleration electrode while eliminating electron release from an electron source and for detecting a change in an emission current corresponding to a change in an acceleration voltage at this time. In addition, the apparatus comprises a means for issuing a cautionary notice or warning when the change of this emission current exceeds a prespecified value. Further, the apparatus comprises a means for letting a dry gas flow in a gap portion between the electron gun's high-voltage cable and the high-voltage introduction insulator to thereby dehumidify said gap portion. With such an arrangement, it is possible to prevent high-voltage discharge due to an increase in water content of the gap portion and also instability of an electron beam due to a leakage current.
An electron beam apparatus having an electron gun for take-out of an electron beam, comprising means for applying a high voltage to an acceleration electrode while eliminating emission of electrons from an electron source and for detecting a change in emission current corresponding to a change of an acceleration voltage at this time.
An electron beam apparatus having an electron gun for take-out of an electron beam, further comprising means for causing a dry gas to flow in a gap portion between a high-voltage introduction cable and a high-voltage introduction insulator of the electron gun to thereby dehumidify said gap portion.
High-voltage discharge prevention method of an electron beam apparatus for use in an electron beam apparatus having an electron gun for take-out of an electron beam, comprising letting a dry gas flow in a gap portion between a high-voltage introduction cable and a high-voltage introduction insulator of said electron gun to thereby dehumidify said gap portion and thus preventing high-voltage discharge due to moisture on a high-voltage cable surface and a high-voltage introduction insulator surface.
Dependencies are inferred from the claim text.