The present disclosure addresses the problem of providing an electron gun that can directly monitor an intensity of an electron beam emitted from a photocathode using only the configuration provided to the electron gun, an electron beam applicator equipped with an electron gun, and a method for controlling an electron gun.
The aforementioned problem can be solved by an electron gun comprising a light source, a photocathode that emits an electron beam in response to receiving light from the light source, an anode, an electron-beam-shielding member with which it is possible to shield part of the electron beam, and a measurement unit that measures the intensity of the electron beam emitted from the photocathode using a measurement electron beam shielded by the electron-beam-shielding member.