电子轰击离子源离子传输效率的数值模拟与实验研究

Numerical Simulations and Experiments of Ion Transfer Rate of Electron Impact Ion Source

针对兰州空间技术物理研究所自研的四极质谱计用电子轰击离子源(EI源)的离子传输效率进行了数值模拟和实验研究。利用模拟仿真软件Simion8.1,采用控制变量法研究了EI源各电极参数对离子传输效率的影响,并进行了实验验证,实验结果与仿真结果一致。结果表明,降低电离室电压、增大电离室与引出极间电压差、调节聚焦极电压至最优值可提高EI源离子传输效率。在四极质谱计中,电离室电压、引出极电压受其他相关因素影响,可调节范围很小,提高EI源离子传输效率的有效方法是调节聚焦极电压。

Numerical simulations and experiments were carried out on the ion transfer rate of electron impact ion source(EI sources)developed by Lanzhou Institute of Physics.Using the simulation software Simon8.1,the influence of every electrode parameter of the EI source on its ion transfer rate was studied by using the control variable method,and the experimental verification was carried out,which proved that the experimental results were consistent with the simulation results.The results show that reducing the ionization chamber voltage,increasing the voltage difference between the ionization chamber and the ejecting pole,and adjusting the focusing pole voltage to the optimal value can improve the rate of EI source ion transfer.In a quadrupole mass spectrometer,the ionization chamber voltage and the ejecting pole voltage are affected by other relevant factors,and the adjustable range is very small,so the effective way to improve the rate of ion transfer of the EI source is to adjust the focusing pole voltage.