霍尔推力器放电室壁面溅射产额研究

Study on Sputtering Yield of Hall Thruster Discharge Chamber Wall

关键词:  霍尔推力器  溅射产额  实验测量  数值模拟

Key words:  Hall Thruster  Sputtering yield  Experiment  Numerical Simulation

摘要:

霍尔推力器放电室壁面经受低能量(不大于300eV)离子的溅射是影响其寿命的关键因素之一。为了获得放电室壁面材料(BNSiO₂)的溅射产额随离子入射角度和能量的变化规律，采用真实霍尔推力器提供275eV的氙离子在真空舱内轰击靶材，利用称重法获得实验参数下的溅射产额。为了克服单纯依靠实验测量耗时耗钱且更低能量的离子溅射实验测量误差会陡然增大的缺点，采用前面实验结果修正了基于蒙特卡罗(MC)方法的SRIM软件溅射产额计算参数，并采用文献实验结果对不同能量下的模拟结果进行验证。在此基础上，用SRIM软件较为详细地考察了入射离子能量低于300eV时入射角度和能量对霍尔推力器放电室壁面材料溅射产额的影响规律。结果表明，溅射产额随离子入射角度先增大后减小，而随入射离子能量则呈现增大的趋势，但当能量小于100eV时，溅射产额逐渐趋于一个非常小的数值。

Abstract:

Discharge chamber wall erosion caused by the accelerated low energy(less than 300eV) ions bombardment is a key factor affecting Hall thruster lifetime. In order to obtain the sputtering yield of the material (BNSiO₂) used in the discharge chamber wall，a real Hall thruster provided the xenon ion with 275eV bombardment of targets in a vacuum chamber. The effects of incident angle on the sputtering yield were investigated by using the weighting method. The sputtering yield caused by the lower energy ion bombardment is hard to be measured precisely and expensive，time-consuming. In order to overcome this shortcoming，the SRIM software，which is based on the Monte Carlo (MC) method，was used to investigate the influences of the incident angle and ion energy on the sputtering yield within the scope of the low ion energy (less than 300eV). The parameters of SRIM were corrected according to the previous experimental data. The experimental results of reference were used to verify the simulating results. After that，the effects of incident angle and ion energy on sputtering yield were investigated. The results show the sputtering yield increased first and then decreased with the incident angle increasing. Under the condition studied，the sputtering yield always decreases as the ion energy decreasing，but when the ion energy is less than 100eV，it gradually moves towards the same and a small value.