Abstract: An electron gun EG in which mixing of secondary electrons is suppressed is provided. The electron gun EG has an electron source 1, an extraction electrode 2 for extracting an electron beam E1 from the electron source 1, and an acceleration electrode for accelerating the extracted electron beam E1. The extraction electrode 2 includes a diaphragm 4 for allowing a part of the electron beam E1 to pass through, a shield 5 positioned above the diaphragm 4 apart from the diaphragm 4, and a shield 6 positioned below the diaphragm 4 apart from the diaphragm 4. The diaphragm 4 has an opening OP4 having an opening diameter D4, the shield 5 has an opening OP5 having an opening diameter D5 which is greater than the opening diameter D4, and the shield 6 has an opening OP6 having an opening diameter D6 which is greater than the opening diameter D4.

Abstract: The invention provides an electron source including a columnar chip of a hexaboride single crystal, a metal pipe that holds the columnar chip of the hexaboride single crystal, and a filament connected to the metal pipe at a central portion. The columnar chip of the hexaboride single crystal is formed into a cone shape at a portion closer to a tip than a portion held in the metal pipe, and a tip end portion having the cone shape has a (310) crystal face. Schottky electrons are emitted from the (310) crystal face. According to the invention, it is possible to provide a novel electron source having monochromaticity, long-term stability of an emitter current, and high current density.

Abstract: The invention provides an electron source including a columnar chip of a hexaboride single crystal, a metal pipe that holds the columnar chip of the hexaboride single crystal, and a filament connected to the metal pipe at a central portion. The columnar chip of the hexaboride single crystal is formed into a cone shape at a portion closer to a tip than a portion held in the metal pipe, and a tip end portion having the cone shape has a (310) crystal face. Schottky electrons are emitted from the (310) crystal face. According to the invention, it is possible to provide a novel electron source having monochromaticity, long-term stability of an emitter current, and high current density.

Abstract: An instrument producing a charged particle beam according to the present invention is provided with: a charged particle source; a plurality of first electrodes disposed along a direction of irradiation of charged particles from the charged particle source; a plurality of insulation members disposed between the first electrodes; and a housing mounted around the plurality of first electrodes. The housing is formed from an insulating solid material, and includes a plurality of second electrodes disposed at positions in proximity to the plurality of first electrodes. At least one of the plurality of second electrodes is electrically connected to at least one of the plurality of first electrodes, each of the plurality of second electrodes having the same potential as the potential of the proximate one of the first electrodes.

Abstract: An instrument producing a charged particle beam according to the present invention is provided with: a charged particle source; a plurality of first electrodes disposed along a direction of irradiation of charged particles from the charged particle source; a plurality of insulation members disposed between the first electrodes; and a housing mounted around the plurality of first electrodes. The housing is formed from an insulating solid material, and includes a plurality of second electrodes disposed at positions in proximity to the plurality of first electrodes. At least one of the plurality of second electrodes is electrically connected to at least one of the plurality of first electrodes, each of the plurality of second electrodes having the same potential as the potential of the proximate one of the first electrodes.

Abstract: In an accelerating tube which uses a conductive insulator, there is a possibility that the dopant concentration on a surface of the conductive insulator becomes non-uniform so that the surface resistance of the conductive insulator becomes non-uniform. Accordingly, a circumferential groove is formed on the inner surface of the conductive insulator accelerating tube in plural stages, and metal is metalized along inner portions of the grooves. When the resistance of a specific portion on the surface of the accelerating tube differs from the resistance of an area around the specific portion, the potential of the metalized region on the inner surface of the accelerating tube becomes a fixed value and hence, the potential distribution on the inner surface of the accelerating tube in the vertical direction can be maintained substantially equal without regard to the circumferential direction.

Abstract: In an accelerating tube which uses a conductive insulator, there is a possibility that the dopant concentration on a surface of the conductive insulator becomes non-uniform so that the surface resistance of the conductive insulator becomes non-uniform. Accordingly, a circumferential groove is formed on the inner surface of the conductive insulator accelerating tube in plural stages, and metal is metalized along inner portions of the grooves. When the resistance of a specific portion on the surface of the accelerating tube differs from the resistance of an area around the specific portion, the potential of the metalized region on the inner surface of the accelerating tube becomes a fixed value and hence, the potential distribution on the inner surface of the accelerating tube in the vertical direction can be maintained substantially equal without regard to the circumferential direction.