The Formation of Metastable and Multiply Charged Ions

The ions emanating from a source involve a distribution of population between different metastable and charge states. Metastable populations confuse the measurement of cross sections; populations of multiply charged ions are desirable for use as beams in collision experiments. The production of ample beams of multiply charged ions requires costly dedicated instrumentation. Low lying metastable states of light ions are heavily populated in laboratory beams and are distributed in a non-statistical fashion. First, this work develops experimental and theoretical techniques for the determination of metastable populations in beams from common laboratory discharges: the confined Electron Cyclotron Resonance (ECR) and open Electron Beam (EB) sources. All charge states of carbon, nitrogen and oxygen are studied. Metastable distributions of singly charged carbon and oxygen ions produced by electron impact of various organic source molecules were measured using a variation of the beam attenuation method. All other species were modeled using the recently developed collisional formulation of Winter. Although this formulation was introduced as a semi-empirical approach, we argue validity by providing a theoretical foundation as well as an extensive experimental verification. Second, we develop a new type of ECR source for the production of multiply charged ions by employing a novel, exclusively permanent magnetic mirror structure and readily available 2.45 GHz microwaves. Stable, microampere beams of multiply charged ions were achieved from a plasma only a few cubic centimeters in volume using just several watts of power operated in the 10^{ -6} Torr range. For example, up to eight times ionized argon was extracted. Small size, simplicity of design, operation and economy of construction make it ideal for retrofit to existing apparatus. Plasma parameters of the source were diagnosed using a numerical charge state model used in conjunction with measured beam charge distributions. Ion confinement times of up to milliseconds and electron temperatures of 150eV were measured indicating the presence of phenomena occurring in conventional ECR sources. Finally, the trapping capabilities of the plasma were utilized in the study of CH^{2+} ion formation.