An object is to provide an electron gun that can extend the lifetime of a photocathode. The object can be achieved by an electron gun including: a substrate having a photocathode film formed on a first face; a light source for irradiating the photocathode film with excitation light; an anode; a heater device for heating the photocathode film and/or the substrate; and an output adjustment device that adjusts a heating temperature of the heater device.

A photoinjector system containing modularly-structured waveguide-mode launcher, which is reversibly connected to the RF gun (containing a tubular construction formed with disattachably-affixed to one another structurally-complementary halves); and a solenoid magnet in operation enclosing such tubular structure in a central hollow. The resulting quality, power, and frequency rate of operation as well as cost of manufacturing and operation of the system are superior as compared with those of a related art system.

A photoinjector system containing modularly-structured waveguide-mode launcher, which is reversibly connected to the RF gun (containing a tubular construction formed with disattachably-affixed to one another structurally-complementary halves); and a solenoid magnet in operation enclosing such tubular structure in a central hollow. The resulting quality, power, and frequency rate of operation as well as cost of manufacturing and operation of the system are superior as compared with those of a related art system.

A HELAC device includes a semiconductor layer that absorbs incident photons, a graphene monolayer disposed over the semiconductor layer, and an insulator layer interposed between the semiconductor layer and graphene monolayer. The graphene monolayer is configured as a gate for the HELAC device while the insulator layer is configured to allow a voltage drop between the semiconductor layer and graphene. Advantageously, the HELAC device is configured to receive photons on an emitter surface and to emit hot electrons therefrom.

A HELAC device includes a semiconductor layer that absorbs incident photons, a graphene monolayer disposed over the semiconductor layer, and an insulator layer interposed between the semiconductor layer and graphene monolayer. The graphene monolayer is configured as a gate for the HELAC device while the insulator layer is configured to allow a voltage drop between the semiconductor layer and graphene. Advantageously, the HELAC device is configured to receive photons on an emitter surface and to emit hot electrons therefrom.

The electron gun is provided with a first anode electrode and a second anode electrode to generate an acceleration and deceleration electric field. A lens electric field makes it possible to irradiate a sample with an electron beam emitted from a part outside an optical axis of the photoelectric film without being blocked by a differential exhaust diaphragm. A wide range of electron beams off-optical axis can be used even in a high-brightness photocathode that requires high vacuum. As a result, the photoelectric film and the electron gun can be extended in life, can be stabilized, and can be increased in brightness. Further, it is possible to facilitate a control of emitting electron beams from a plurality of positions on the photoelectric film, a timing control of emitting electron beams from a plurality of positions, a condition control of an electron beam in an electron microscope using electron beams.

The electron gun is provided with a first anode electrode and a second anode electrode to generate an acceleration and deceleration electric field. A lens electric field makes it possible to irradiate a sample with an electron beam emitted from a part outside an optical axis of the photoelectric film without being blocked by a differential exhaust diaphragm. A wide range of electron beams off-optical axis can be used even in a high-brightness photocathode that requires high vacuum. As a result, the photoelectric film and the electron gun can be extended in life, can be stabilized, and can be increased in brightness. Further, it is possible to facilitate a control of emitting electron beams from a plurality of positions on the photoelectric film, a timing control of emitting electron beams from a plurality of positions, a condition control of an electron beam in an electron microscope using electron beams.

An object is to provide an electron gun that makes it possible to verify whether or not an electron beam emitted form a photocathode is misaligned from a designed emission center axis. The object can be achieved by an electron gun including: a light source; a photocathode; and an anode. The electron gun includes an intermediate electrode arranged between the photocathode and the anode, an electron beam shielding member configured to block a part of an electron beam, a measurement unit configured to measure an intensity of an electron beam blocked by the electron beam shielding member, and an electron beam emission direction deflector arranged between the anode and the electron beam shielding member and configured to change a position where an electron beam that passed through the anode reaches the electron beam shielding member. The intermediate electrode has an electron beam passage hole and a drift space.

An object is to provide an electron gun that makes it possible to verify whether or not an electron beam emitted form a photocathode is misaligned from a designed emission center axis. The object can be achieved by an electron gun including: a light source; a photocathode; and an anode. The electron gun includes an intermediate electrode arranged between the photocathode and the anode, an electron beam shielding member configured to block a part of an electron beam, a measurement unit configured to measure an intensity of an electron beam blocked by the electron beam shielding member, and an electron beam emission direction deflector arranged between the anode and the electron beam shielding member and configured to change a position where an electron beam that passed through the anode reaches the electron beam shielding member. The intermediate electrode has an electron beam passage hole and a drift space.

A photocathode emitter can include a transparent substrate, a photocathode layer, and a plasmonic structure array disposed between the transparent substrate and the photocathode layer. The plasmonic structure can serve as a spot-confining structure and an electrical underlayer for biasing the photocathode. The plasmonic structure can confine the incident light at subwavelength sizes.