热扩散阴极微区热电子发射特征研究

Study on Micro-area Thermionic Emission Characteristics of Thermal Dispenser Cathodes

在微米尺度开展热扩散阴极热电子发射特征研究,对了解阴极电子发射过程和理解阴极发射机理有一定的参考价值。本文利用深紫外激光光发射/热发射电子显微镜系统,对浸渍钡钨阴极、覆膜浸渍扩散阴极、浸渍钪酸盐阴极以及新型浸渍钪型阴极,开展了光电子、热电子显微成像分析。结果显示,浸渍钡钨阴极的热电子发射区域主要位于表面局部孔隙中;覆膜浸渍扩散阴极的电子发射区域沿孔隙向覆膜的钨颗粒表面延伸,阴极发射面积明显增加;浸渍钪酸盐阴极与新型浸渍钪型阴极表面拥有一定数量的高发射点,浸渍钪酸盐阴极的高发射点几乎都分布在阴极表面的钨颗粒边缘,而新型浸渍钪型阴极的高发射点不仅存在于钨颗粒边缘,同时也出现在部分钨颗粒表面。

The research on electron emission characteristics of thermal dispenser cathodes in micro-scale has certain reference value for understanding electron emission process and cathode emission mechanism.In this work,DUV-PEEM/TEEM is used to carry out photo emission electrons and thermal emission electrons imaging analysis for impregnated Ba-W cathode,coated impregnated dispenser cathode,impregnated scandate cathode and new impregnated scandium cathode,respectively.The results show that the electron emission of impregnated Ba-W cathode is mainly located at local pores.For coated impregnated dispenser cathodes,as emission regions extend from pores to tungsten particles,the cathode emission areas increase significantly.In addition,the surfaces of impregnated scandate cathodes or new impregnated scandium cathodes have a certain amount of high emission spots.The high emission spots of impregnated scandate cathodes are almost entirely distributed on the edges of tungsten particles,while the high emission spots of new impregnated scandium cathodes are distributed on both the edges and some surfaces of tungsten particles.