Abstract: In the development process of the microwave tubes, the main purpose of vacuum degassing system for the electron gun is to obtain the data between current/voltage and temperature, to test the quick start parameter, to measure thermal expansion and to minimize the material evapotranspiration and outgassing. According to the relation between structure and property of the electron gun, two operating station vacuum degassing system was designed and developed with the function of temperature, thermal expansion and other measure property. The final system pressure is better than  2×10^-7 Pa. In the vacuum degassing system, mechanical pump is used as the backing up pump, while the molecular pump and the ion pump are the main pumps. Each operating station can work simultaneously to improve the quality and to save time for increasing the efficiency. Indicator lights are equiped with the system to prevent the potential problems for the electron guns or the vacuum system that is caused by misoperation. A large amount of data obtained from experiments verifies the working principal, structure design and good properties of the system. It is applicable to different types of electron guns for microwave tubes, which has important significance in the small amount production of klystrons.

Key words: microwave tubes')">microwave tubes, electron gun, vacuum degassing system, ultrahigh vacuum, measuring