本文基于IE514分离规结构,建立了碳纳米管阴极电离规物理模型,根据电离规标准方程,利用离子光学模拟软件SIMION8.0分别研究了电极电压对灵敏度和Igrid/Ie的影响.结果表明,随着阳极/门极电压比值增大(Vgrid/Vgate),Igrid/Ie也将增大,然而,当阳极电压增大时,会导致灵敏度降低,进而影响真空测量下限的延伸;该模拟结果与相关文献报道的实验结果符合性很好.因此,选择合适的电极电压,将有利于提高灵敏度,增大阳极电流,进一步延伸真空测量下限.本文所采用的数值模拟方法可推广应用于各种新型碳纳米管阴极极高真空电离规的研发和理论分析中,为解决极高真空测量难题提供了有效的研究途径.
Theoretical studies of electrodes potential influence on the sensitivity and ratio of anode current and emission current (Igrid/Ie) will be beneficial for providing theoretical basis and experimental instruction in the research of ionization gauge with carbon nanotubes cathode. In this paper, based on the structure of IE514 extractor gauge, the model of carbon nanotube ionization gauge is built by ion optic simulation software SIMION 8.0. And the influence of electrode potential on the sensitivity and Igrid/Ie is discussed. Results show that with increasing ratio between anode voltage and gate voltage (Vgnd/Vgate), Igrid/Ie increases, while the sensitivity of the gauge decreases with the increase in anode voltage, which would further affect the extension of vacuum measurement lower limit. Moreover, the simulation results are in good agreement with the experimental data reported. Consequently, it is very important to improve the sensitivity, anode current and extension of measurement lower limit to set up an appropriate electrode voltage. In addition, the method adopted in this paper can be extended to the research and development of new-styles of extremely high vacuum ionization gauge of carbon nanotube cathode, which could provide an effective method to resolve the problem of extremely high vacuum measurement.