钼的二次电子发射特性研究

The secondary electron emission characteristics of molybdenum

摘要:

钼具有高熔点、低的热膨胀系数和极佳的稳定性，在等离子体推进和电真空器件领域具有广阔的应用前景，其二次电子发射特性也逐渐引起了研究者们的关注。本文首先对钼的二次电子发射系数(Secondary Electron Yield，SEY)和二次电子能谱(Secondary Electron Spectrum，SES)展开实验研究，其次利用相关唯象模型对测试数据进行了分析；最后建立了钼SEY的蒙特卡罗模型，用于分析功函数对SEY的影响规律。研究结果表明：钼SEY的最大值为1.77，相比镀银铝合金明显降低。当入射电子能量改变时，SES中真二次电子峰的最可几能量基本不变，而弹性背散射电子峰的位置和强度均随之改变。在各类二次电子中，真二次电子受功函数的影响最大。

Abstract:

Molybdenum has high melting point, low thermal expansion coefficient and excellent stability. It has broad application prospects in plasma propulsion and electric vacuum devices so that its secondary electron emission characteristics have gradually attracted the attention of researchers. Firstly, the secondary electron yield (SEY) and secondary electron spectrum (SES) of molybdenum were studied experimentally. Then the test data were analyzed by the relevant model. Finally, the SEY model of molybdenum is established by Monte Carlo method to analyze the influence of work function on SEY. The results show that the maximum value of SEY is 1.77, which is significantly lower than that of silver-plated aluminum alloy. When the incident electron energy changes, the most probable energy of the true secondary electron peak of the SES is basically unchanged, while the position and intensity of the elastic backscattered electron peak change accordingly. Among all kinds of secondary electrons, true secondary electrons are most affected by the work function.