Switching Function Membrane Preparation And Inhibition Of Collecting Secondary Electron Emission Mechanism Research

Traveling wave tube amplifiers(TWTs) employed in many areas and systems become to be an important high-power microwave resource, for their high gain, broad bandwidth, low noise and good flexibility. An important consideration in the development of TWTs is the achievement of high output power. High output power can be get by high TWTs efficiency. Similarly, high TWTs efficiency can be get by high collector efficiency. Multistaged depressed collector(MDC) of TWTs is the device that used for collecting spent beam according to their speed. Surface coating method is used to suppress the secondary electron emission, thereby enhancing the efficiency of the MDC.Secondary electron emission processes was discussed by a three-step process: penetration of the primary electrons, transmission of the secondary electrons through the material, and final escape of the secondary electrons over the vacuum barrier. This paper is based on the theory of the third stage, films with high work function were coated on the collector to suppress the emission of secondary electrons.The result of Hf ion plasma source ion implantation Cu are presented. SRIM (The Stopping and Range of Ions in Matter) was used to simulate the process of Hf ion plasma source ion implantation Cu substrate. The relationship between energy and stopping power, the relationship between energy and range, and ion distribution of different implantation conditions were simulated. The analysis of simulation results was also included in the paper. Simulation results show that:nuclear stopping power dominates when the energy is lower than6MeV, otherwise electronic stopping power dominates, there are a Bragg peak of the energy deposition process and the phenomena that the mass deposition area concentrates, the rang generally increases as the energy increases.The TiN film was prepared by arc ion plating method, and the parameters were designed through orthogonal experiment table, Ir and Hf film were prepared by magnetron sputtering method, Au, Ni and Pt films were prepared by electroplating. The film thickness, surface morphology and surface roughness were respectively measured by scanning electron microscopy (SEM) and atomic force micros-copy (AFM), secondary electron emission coefficient was measured by a specific device. The experimental results were analyzed. The impact of bias voltage on the film thickness and surface roughness were studied, the secondary electron emission coefficient of the above films were compared, the affect of surface roughness and substrate on secondary electron emission coefficient were analyzed.The results show that within a certain range, the film thickness decreases as the bias increases, rms roughness Rq is minimum for TiN film when the bias voltage is150V, the above films all can reach the effect of inhibition of secondary electron emission, the TiN film with blasting substrate and Ni film are the best, and the rougher surface has the lower secondary electron emission coefficient.