6.4 GHz VEC-ECR Ion Source and its Vacuum Aspects

摘要

on the equilibrium charge state distribution. To minimize charge exchange loss due to recombination of multiply charged ions with neutral atoms, the essential boundary condition of neutral to electron density ratio (n_0_e) on atomic mass for ionization of hydrogen like ions has been considered in the design. Considering the stepwise multiply charged ion production criterion with minimum charge exchange loss, it is found that the production of Ne~(10+) ions requires a pressure of 1.4X10~(-7) Torr for 6.4 GHz operation. The ionization chamber is mainly pumped by the plasma. An additional pumping speed has been provided through extraction hole and pumping slots. Plasma pumping and the neutral burn out are considered in the design based on the plasma size and the nature of the gas.