Ionbeam

Ion beam is a stream of charged atoms or molecules accelerated to high kinetic energy and directed at a target. Ion beams are produced by ion sources that ionize matter and extract charged species. Beams may be composed of a single ion species or mixtures and can include isotopes. Energies commonly span from tens of keV to several GeV, with beam currents ranging from nanoamperes to milliamperes. Key properties include energy, current, focus, and emittance.

Ion beams are generated in dedicated sources such as plasma-based systems (duoplasmatron or glow-discharge), electron cyclotron resonance (ECR) sources, or, for focused ion beams, liquid metal ion sources. Ions are accelerated by high-voltage potentials, then steered and focused with magnetic and electrostatic optics before reaching the target. Focused ion beam systems can produce nanometer-scale spots for milling, deposition, and imaging.

Applications span materials analysis, modification, and medical therapy. In materials science, ion beams enable depth profiling and compositional analysis via techniques such as secondary ion mass spectrometry (SIMS), Rutherford backscattering, and particle-induced X-ray emission (PIXE). In fabrication, ion implantation introduces dopants into semiconductors, modifies surface properties, or enables etching and patterning with focused beams. In medicine, proton and carbon ion beams are used in radiotherapy, offering favorable dose localization and biological effectiveness.

Safety and practical considerations include radiation shielding, activation of materials, vacuum requirements, and management of beam-induced damage and contamination. System cost and maintenance, along with precise metrology and dose control, influence reliability. The field continues to advance in source efficiency, beam shaping, and in situ diagnostic capabilities.