Simulation of Charge Exchange Interactions in a Tandem Accelerator for Proton Irradiations

A tandem proton accelerator is being developed to supply MeV proton beams for industrial applications such as high-energy implantations. Because the aim of this accelerator is industrial applications for which the beam quality is not an important factor, an accelerator with a high current and a simple system has been developed. The accelerator consists of a negative hydrogen ion source, an Einzel lens, accelerating tubes, a charge stripper, a 1MV Cockroft-Walton high-voltage power supply, a high-pressure insulating gas system and an irradiation system. Due to the high current, a gas stripper with nitrogen is used. With a straight optical geometry, the interaction of negative, neutral and positive hydrogen with the residual gas, which is mainly from the stripper gas, during their passage from the ion source to the target is simulated with a Monte Carlo code programmed with C language. The simulation result shows that a 150-kV terminal voltage is the lower limit for this accelerator due to the more than 20 % beam loss and even at higher voltage, off-energy particle of a few percent can be irradiated on targets. KCI Citation Count: 1