The Design And Research Of Electron Gun In Vacuum Device

Microwave vacuum devices were born in the 1930 s during World War II, due to the urgent need for radar, communications, navigation, electronic countermeasures, which has been an unprecedented development. After World War II, many microwave vacuum devices have been invented. Until the end of the last mid-century, microwave vacuum devices still play a very important role in our national life and military applications. Despite the strong invasion of semiconductor devices, those devices, which have high frequencies and power, still have an absolute advantage in the end of the century. But as the ”heart”of microwave vacuum device, the low speed spread and high quality electron gun are also urgent.In microwave vacuum devices, the electron beam is accelerated to near the speed of light, carrying a very high energy. Thus in modern military electronic equipment, to be invincible, high power microwave vacuum devices still play a very important role. The development of ordinary microwave vacuum devices, such as traveling wave tube, gyro tube and backward wave tube, has been quite mature. But with the increase in the operating frequency, due to limitations of the existing mechanism, ordinary microwave vacuum devices in the millimeter wave band presente many flaws: the processing is extremely difficult, high-cost, small size parts, the entire tube is not conducive to small devices, limited emission density of cathode, the cathode and the entire pipe have cooling difficulties, making it difficult to achieve high output power and efficiency. Thus, in addition to improve the performances of the vacuum tube in different aspects, the exploration of new mechanisms and new ways of solving related problems in vacuum device is a very significant issue. Combining the project in our group, based on the research of the traditional vacuum device in the electron gun, designed a magnetron injection gun with low speed spread and high beam current which is applicated to 140 GHz, MW-grade gyrotron.On the basis of the characters of carbon nanotube: fast response, high emission current density, small size of processing, high efficiency, low power consumption and other series of advantages, I made some improvements on the electron gun and desined a carbon nanotube cold cathode electron gun for traveling wave tube. The main work includes:1.The development trend of electron gun in vacuum device is discussed in this paper.The development status of double anode magnetron injection electron gun and carbon nanotube cold cathode electron gun is discussed.2.In the description and derivation of magnetron injection electron gun theory formula, I designed a 140 GHz double anode magnetron injection gun for gyrotron by electromagnetic simulation software, and discussed the range of the parameters in the magnetron injection gun and the selection of the parameters.3.The carbon nanotube field emission theory, mechanism, simulation modeling and experimental tests are discussed in detail.4.The existing traditional elaborated TWT electron gun theory was discussed firstly,this carbon nanotube materials were applied in TWT electron gun, and a simulation study is dong. Three types of gun were designed: CNT cold cathode field emission electron gun arc, carbon nanotubes three cold cathodes field emission electron gun anode, a carbon nanotube cold cathode field emission planar electron gun.