Study on the Influence of Pressure on Ion Extraction Characteristics

Many ion sources need to work in the order of $10^{-3}$ –1-Pa pressure, so the influence of these pressures on ion extraction characteristics has been attracted attention. In this article, based on 2-D space and 3-D velocity (2D3V) particle-in-cell-coupled Monte Carlo collision (PIC-MCC) method, a simplified simulation model of argon ion extraction process under an extraction voltage of −10 kV is established. The influence of argon pressure on the density and velocity of electrons and ions is obtained. Then, the reason why the extracted ion current decreases obviously when the argon pressure increases to 1 Pa is explained. That is, the probability of elastic collision and charge exchange between argon ions and argon atoms increases obviously, which leads to the deceleration and divergence of argon ion beam. This provides support for further understanding of ion extraction characteristics and influencing factors.