Ionstråle

Ionstråle, or ion beam, is a stream of charged atoms or molecules accelerated to high kinetic energy and directed along a defined path. Ionstråle are produced by ion sources that generate ions in a plasma or gas and extract them through electric fields. Common sources include Penning and duoplasmatron sources for low to medium energies, and electron cyclotron resonance (ECR) or microwave sources for highly charged ions. Ions are often stripped to multiple electrons, producing positive ions with charge state q. The beam is then accelerated by applying a potential difference, imparting energy E = qV, and steered and focused by magnetic and electrostatic elements to form a narrow, high-intensity beam.

In transport, quadrupole magnets and electrostatic lenses shape the beam; vacuum is essential to minimize collisions. Diagnostics like Faraday cups measure current; beam profile monitors and emittance measurements assess quality. The energy range from keV to MeV is common; higher energies exist in accelerator facilities. The beam's composition depends on ion source gas and charge state, with protons, deuterons, and heavier ions used depending on application.

Applications of ionstråle include ion implantation to modify material properties and semiconductor doping; surface modification such as sputtering, carburizing, or hardening; ion beam milling and lithography; and analytical techniques like Rutherford backscattering spectrometry (RBS), particles-induced X-ray emission (PIXE), secondary ion mass spectrometry (SIMS), and elastic recoil detection analysis (ERDA) for composition analysis. Ion beam analysis uses broad beams or microbeams for imaging and depth profiling. Ionstråle therapy uses protons or heavier ions for cancer treatment in medical facilities.

Safety and handling are essential: ionstråle produce radiation and activation; shielding and interlocks, along with high vacuum systems and regular monitoring, are required.