Speaker
Description
Low-energy broad beam ion sources are essential components in a wide range of advanced technologies, including neutral beam injectors (NBIs) for fusion research, plasma diagnostic systems, electric propulsion for spacecraft, and ion-based material surface modification processes. These ion sources produce ion beams by extracting and accelerating ions through multi-aperture, multi-grid structures under the influence of applied electric fields. The positive space charge of the extracted ion beam is compensated by electrons supplied either through charge-exchange processes or by thermionic emission from heated cathodes. Beam divergence, which measures the spread of ions in the radial direction and impacts the beam quality and transport efficiency, is influenced by factors such as beam perveance and space charge effects. In this study, the radial profiles of argon and xenon ion current densities from a ring cusp ion source were experimentally measured using a two dimensional Multi-channel Faraday cup array. The measured beam divergences are benchmarked against self-consistent beam extraction and transport simulations using the AXCEL-INP code and CST PARTICLE STUDIO. Based on these results, the role of ion mass and space-charge effects in ion beam divergence will be discussed.