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微波真空电子器件广泛应用于雷达、卫星通信、电子加速器及未来军事前沿的高功率微波武器等方面,担当电子发射的阴极是微波真空电子器件中最为核心的部分.纳米材料具有许多不同于块体材料的物理化学特性,利用纳米材料对传统的扩散阴极进行表面改性,制备出热电子发射性能良好的新型阴极,对于推动高功率微波真空电子器件的发展具有十分重要的意义.本文采用直流磁控溅射复合金属靶的方法制备出粒径分布均匀的直径为20 nm的金属纳米粒子,并测试研究了纳米粒子薄膜的热稳定性.采用飞行时间质谱(To FMS)测试了真空本底和纳米粒子薄膜阴极、传统覆膜阴极等各种阴极蒸发物的成分,测试结果表明飞行时间质谱仪具有很高的灵敏度,比较了不同阴极蒸发速率的大小,发现纳米粒子薄膜阴极比普通覆膜阴极的蒸发速率降低约30%.研究了覆纳米粒子薄膜钡钨阴极的发射特性,阴极直流发射电流密度达到31.4 A/cm2,且拐点非常明显,寿命超过600小时;阴极的脉冲发射电流密度达到108 A/cm2,寿命达到1500小时.
Microwave vacuum electronic devices are widely used in radar, satellite communications, electronic accelerator and the future of the military cutting-edge high-power microwave weapons and other aspects, the cathode responsible for electron emission microwave vacuum electronic devices is the most core part of nano-materials have many different from the block Material physical and chemical characteristics, the use of nano-materials on the traditional diffusion cathode surface modification to prepare a good new type of cathode for the performance of the hot electron emission, for promoting the development of high power microwave vacuum electronic devices is of great significance.In this paper, DC magnetic Controlled sputtering of composite metal target method to prepare a uniform diameter of 20 nm diameter metal nanoparticles and tested the thermal stability of the nanoparticle film.Flow time-of-flight mass spectrometry (To FMS) was used to test the vacuum background and The results show that the time-of-flight mass spectrometer has a high sensitivity, compared with the size of the different cathode evaporation rate, found that the cathode of the nanoparticle film than ordinary coated cathode Of the evaporation rate is reduced by about 30% The cathodic emission current density reaches 31.4 A / cm2, and the inflection point is very obvious, with a life span of more than 600 hours. The pulse current density of the cathode reaches 108 A / cm2 and the life time reaches 1500 hours.