Electron Induced Outgassing Test Device

An electron induced outgassing test device was developed to measure the material outgassing properties under electron bombarding, and one of the most important units is the electron beam generator, which has many adjustable parameters that can affect the output beam quality. Experiments were carried out to measure the influence factors of electron beam spot and beam current. The results showed that both the focus voltage and grid voltage have a direct effect on the size of the electron beam spot. However, the energy voltage almost has no effect on the spot diameter. In addition, either cathode voltage, electron energy, or grid voltage can affect the emission current, and so as to the outgoing electron beam current, although the changing trend of the influence curve varies. In order to demonstrate the testing capability of the device for electron-stimulated desorption and outgassing, 316 L stainless steel with degassing treatment was selected as the test sample, and the outgassing characteristics before and after electron bombardment were tested and compared three times. It is indicated that the electron induced outgassing rate can be determined obviously for the sample. The main outgassing component under electron bombardment changes from N₂/CO to H₂.