Inhibition Of Twt Multistage Depressurization Collection Of Secondary Electron Emission Research

The demands on Space Travelling "Wave Tubes(TWTs) used for satellite communications and navigations have increased greatly in recently years, while satellite industries require ever higher performance of space TWTs, such as high overall efficiency, a long lifetime and high reliability. Higher overall efficiency of the devices means not only lower power consumption but also minimized and light weight power supplies. At the same time, it also provides a probability to improve the reliability and prolong the lifetime of the devices, thus bringing enormous economy benefits. At present, China just started the research on novel Ka and higher frequence millimeter wave band satellite communication system. It is imminent to develop our own Space TWTs having a higher overall efficiency.The goal of this research is to improve the overall efficiency of Space TWTs by ion surface treatment of multistage depressed collector (MDC). Based on the some analysis on the theory of suppressing secondary electron emission, a special ion beam treatment system has been developed in our lab. The process for MDC surface treatment was also investigated in the project. The main contents of this thesis include:1. The theories of secondary electron emission, ion beam bombardment surface treatment and increasing overall efficiency of Space TWTs by treating the material surface of MDC.2. Development of the special ion beam surface treatment equipment for suppressing the secondary electron emission from MDC in Space TWTs.3. Studies on the process of ion beam treatment, including the effect ion beam duty cycle and temperatures on secondary electron emission coefficient and surface conditions.4. Experimental results from oxygen-free copper samples and MDC samples. Secondary electron emission coefficient from ion treated oxygen-free copper surface was only about60%of that of the untreated surface. On the other hand, the overall efficiency of K-band and Ka-band Space TWTs using ion treated MDC increased by3-7%, as compared to that of space TWTs with MDC not treated. To reduce secondary electron emission from MDC and improve the overall efficiency of Space TWTs, we have developed a first ion treatment system in China, with necessary processing techniues, which have been incorporated into the fabrication proessses of our space TWTs in the Institute.