栅网式离子能量分析仪的模拟及实验研究

Numerical Simulation and Experimental Evaluation of Gridded Ion Energy Analyzer

为了研究离子源所发射出的离子能量分布规律,本文采用离子光学模拟软件Simion7.0对四栅网离子能量分析仪中网格参数进行了相关模拟实验,理论分析表明,栅网透射率对离子能量的测试有一定影响,在设计栅网式离子能量分析仪时应根据所测等离子体的特性确定网格大小和网格间距。采用研制的四栅网离子能量分析仪对宽束冷阴极离子源在不同条件下的离子能量分布进行了实验测试,测试结果表明,离子源的工作真空度越低,测得的离子平均能量越小;当改变离子源的引出电压时,离子平均能量测试误差小于2%。

The impacts of the major factors,including the mesh size,fdament diameter, and grid spacing of the four-grid ion analyzer, and its extraction voltage and operation pressure as well, on measurement of the ion energy distribution of an ion source were mathematically modeled, experimentally evaluated, and simulated with simulation software Simion7. 0. The simulated results show that depending on mesh size and grid spacing, the grid transmittance considerably affects the ion energy distribution. The ion energy distribution of the broad-beam cold cathode ion source was measured with the lab-built four-grid ion energy analyzer. The experimental results reveal that the average ion energy decreased with anincrease of the pressure. Measured at different extraction voltages, the largest discrepancy between the measured and simulated av-erage ion energies was found to be less than 2%.