US 12,334,297 B2
Electron gun and electron beam application device
Hideo Morishita, Tokyo (JP); Takashi Ohshima, Tokyo (JP); Yoichi Ose, Tokyo (JP); Toshihide Agemura, Tokyo (JP); and Makoto Kuwahara, Nagoya (JP)
Assigned to HITACHI HIGH-TECH CORPORATION, Tokyo (JP)
Appl. No. 18/036,217
Filed by Hitachi High-Tech Corporation, Tokyo (JP)
PCT Filed Dec. 22, 2020, PCT No. PCT/JP2020/047913
§ 371(c)(1), (2) Date May 10, 2023,
PCT Pub. No. WO2022/137332, PCT Pub. Date Jun. 30, 2022.
Prior Publication US 2023/0402246 A1, Dec. 14, 2023
Int. Cl. H01J 37/073 (2006.01); H01J 3/02 (2006.01)
CPC H01J 37/073 (2013.01) [H01J 3/021 (2013.01); H01J 2237/06333 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An electron gun, comprising:
a photocathode including a substrate and a photoelectric film formed on the substrate;
a light source configured to emit a pulsed excitation light;
a condenser lens facing the substrate of the photocathode and configured to condense the pulsed excitation light toward the photocathode;
a first anode electrode and a second anode electrode facing the photoelectric film of the photocathode;
a first power supply configured to apply a first control voltage between the first anode electrode and the second anode electrode; and
a second power supply configured to apply an acceleration voltage between the photocathode and the second anode electrode, wherein
the first anode electrode is disposed between the photocathode and the second anode electrode,
a surface of the first anode electrode facing the second anode electrode has a recessed shape, and a surface of the second anode electrode facing the first anode electrode has a protruding shape, and
the first control voltage is set such that the photocathode has a surface electric field intensity higher than a surface electric field intensity when the acceleration voltage is applied to the second anode electrode in the absence of the first anode electrode.