Production of negative ion beams through charge transfer between negative hydrogen ion beams and non-metallic gases

Abstract

Negative ion beam applications in tandem accelerators are used for nuclear research, environmental studies, materials analysis, medical treatments, and ion implantation in semiconductor devices. Conventional methods for generating negative ions for tandem accelerators rely on metallic vapors (typically alkali) for charge exchange, which pose challenges like contamination, electrical shorting and breakdowns, and maintenance issues. To address these drawbacks, this work explores an alternative approach to produce negative ions using a non-metallic charge exchange process. It involves directing negative hydrogen ions into neutral gases within a specially designed charge exchange cell equipped with an electrostatic accelerator. The method is applied to various gas targets, including He, H2 and O2, to accelerate and measure resulting negative ions. This innovative approach aims to mitigate contamination concerns associated with metallic vapor double-charge exchange methods and explore novel avenues for negative ion production through charge transfer. Any newly formed negative ion beam current conversion ratios from the incident H− beam will be reported as progress in this research.