Electron beam application device

An electron beam application device comprising:

• an electron gun having an electron probe radiation region and an activation region, and including a photocathode configured to be transferred between the electron probe radiation region and the activation region;
• an electron optical system column into which an electron beam emitted by irradiating the photocathode disposed in the electron probe radiation region with excitation light is introduced;
• an activation mechanism disposed in the activation region;
• a control device configured to control the activation mechanism;
• and
• a computer configured to control the control device and execute a surface activation process on the photocathode by the activation mechanism, wherein
• the activation mechanism includes
• a light source device configured to irradiate the photocathode disposed in the activation region with the excitation light,
• an alkali metal source configured to be deposited on a surface of the photocathode in the surface activation process,
• a first power source configured to energize the alkali metal source to generate alkali metal vapor,
• a heat generating element,
• an oxygen generation unit configured to generate oxygen by heating the heat generating element, and
• an emission current meter configured to monitor an emission current generated by electron emission when the photocathode is irradiated with the excitation light from the light source device, and
• in the surface activation process, the computer performs control such that the photocathode is irradiated with the excitation light from the light source device, an emission current amount of the photocathode is monitored by the emission current meter, the heat generating element is heated to generate oxygen by the oxygen generation unit, and the heating of the heat generating element is stopped when the emission current amount of the photocathode satisfies a predetermined stop criterion.