Photocathode kit, electron gun, and electron beam application device

Abstract

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.

Dependencies are inferred from the claim text.