The present invention addresses the problem of providing a method for automatically adjusting an electron beam emitted from an electron gun equipped with a photocathode to the incident axis of an electron optical system.

[Solution] An incident axis alignment method for an electron gun equipped with a photocathode, the electron gun being capable of emitting an electron beam in a first state due to the photocathode being irradiated with excitation light, and the method including at least an excitation light radiation step, a first excitation light irradiation position adjustment step for changing the irradiation position of the excitation light on the photocathode and adjusting the irradiation position of the excitation light, and an electron beam center detection step for detecting whether a center line of the electron beam in the first state coincides with an incident axis of an electron optical system.

The present invention addresses the problem of providing a method for automatically adjusting an electron beam emitted from an electron gun equipped with a photocathode to the incident axis of an electron optical system.

[Solution] An incident axis alignment method for an electron gun equipped with a photocathode, the electron gun being capable of emitting an electron beam in a first state due to the photocathode being irradiated with excitation light, and the method including at least an excitation light radiation step, a first excitation light irradiation position adjustment step for changing the irradiation position of the excitation light on the photocathode and adjusting the irradiation position of the excitation light, and an electron beam center detection step for detecting whether a center line of the electron beam in the first state coincides with an incident axis of an electron optical system.

Provided is a photocathode kit that does not require adjustment of the distance between a photocathode film and a lens focusing on the photocathode film when the photocathode and the lens are installed inside an electron gun. The photocathode kit includes: a photocathode including a substrate in which a photocathode film is formed on a first surface; a lens; and a holder that holds the substrate and the lens, and the holder has a retaining member that retains the photocathode film and the lens to be spaced apart by a predetermined distance, and a first communication path that communicates between inside of the holder and outside of the holder.

Provided is a photocathode kit that does not require adjustment of the distance between a photocathode film and a lens focusing on the photocathode film when the photocathode and the lens are installed inside an electron gun. The photocathode kit includes: a photocathode including a substrate in which a photocathode film is formed on a first surface; a lens; and a holder that holds the substrate and the lens, and the holder has a retaining member that retains the photocathode film and the lens to be spaced apart by a predetermined distance, and a first communication path that communicates between inside of the holder and outside of the holder.

A scanning electron beam apparatus which two-dimensionally scans a sample by an electron beam, to achieve high resolution even with a photoexcited electron source. The electron beam apparatus includes a photocathode including a substrate having a refractive index of more than 1.7 and a photoemissive film, a focusing lens configured to focus an excitation light toward the photocathode, an extractor electrode disposed facing the photocathode and configured to accelerate an electron beam generated from the photoemissive film by focusing the excitation light by the focusing lens and emitting the excitation light through the substrate, and an electron optics including a deflector configured to two-dimensionally scan a sample by the electron beam accelerated by the extractor electrode. For a spherical aberration of the focusing lens, a root mean square of the spherical aberration on the photoemissive film is equal to or less than 1/14 of a wavelength of the excitation light.

A photocathode 4 includes an optically transparent conductive layer provided between a translucent substrate and a photoelectric conversion layer. The optically transparent conductive layer is formed of a constituent material including carbon. A Raman spectrum of the constituent material has a peak of a band, a peak of a band, a peak of a band, and a peak of a band.

A photocathode 4 includes an optically transparent conductive layer provided between a translucent substrate and a photoelectric conversion layer. The optically transparent conductive layer is formed of a constituent material including carbon. A Raman spectrum of the constituent material has a peak of a band, a peak of a band, a peak of a band, and a peak of a band.

An image sensor has a photocathode window assembly, an anode assembly, and a malleable metal seal. The photocathode window assembly has a photocathode layer. The anode assembly includes a silicon substrate that has an electron sensitive surface. The malleable metal seal bonds the photocathode window assembly and the silicon substrate to each other. A vacuum gap separates the photocathode layer from the electron sensitive surface. A first electrical connection and a second electrical connection are for a voltage bias of the photocathode layer relative to the electron sensitive surface.

A photocathode emitter includes a transparent substrate, a photocathode layer, and a plasmonic structure array disposed between the transparent substrate and the photocathode layer. The plasmonic structure array is configured to operate at a wavelength from 193 nm to 430 nm. The plasmonic structure array can be made of aluminum. An electron beam can be generated from a light beam directed at the plasmonic structure array of the photocathode emitter.

A photocathode emitter includes a transparent substrate, a photocathode layer, and a plasmonic structure array disposed between the transparent substrate and the photocathode layer. The plasmonic structure array is configured to operate at a wavelength from 193 nm to 430 nm. The plasmonic structure array can be made of aluminum. An electron beam can be generated from a light beam directed at the plasmonic structure array of the photocathode emitter.