Electron beam application device, and electron beam emission method for electron beam application device

An electron beam emission method in an electron beam applicator,

• wherein the electron beam applicator includes an electron gun section, a main body section, and a control unit,
• wherein the electron gun section includes
• a light source,
• a photocathode that emits an electron beam in response to receiving excitation light emitted from the light source, and
• an anode,
• wherein the main body section includes
• an objective lens that converges an electron beam emitted from the electron gun section,
• the emission method comprising:
• an electron beam emission step of emitting an electron beam from the photocathode in response to receiving excitation light emitted from a light source;
• an electron beam traveling step of causing an electron beam emitted by the electron beam emission step to travel toward the objective lens arranged in the main body section;
• and
• an electron beam convergence step of converging the electron beam, which reached the main body section by the electron beam traveling step, by using the objective lens, and
• wherein in the electron beam traveling step, the electron beam emitted from the photocathode travels without having a focal point until reaching the objective lens.