Ion Source Research

Background

In order to accelerate a particle beam, one must use electromagnetic fields. Electromagnetic fields can accelerate only charged particles. Therefore, if the particles have no net charge, like the atoms, one must first ionize them, that is, convert them into charged particles (ions). This is done by removing electrons from the atoms in devices called ion sources. High performance ion sources are capable of removing many electrons from an atom, and they do this very efficiently.

Ion source researchers investigate the complex physical and chemical processes that determine the complex properties of the ionized vapor — or plasma — inside these devices. The knowledge gained helps them design and build improved ion sources that produce more ions, use less material, are more stable and easier to operate, and are, hopefully, less costly to build. Ion source researchers apply knowledge from many different areas of science, e.g., plasma physics, electromagnetism, chemistry, atomic physics, and the physics of ion-atom, ion-ion, electron-atom, and electron-ion collisions.

The Role of NSCL

NSCL has always been at the front line of the research and development of one very important type of ion source, the Electron Cyclotron Resonance (ECR) ion source. NSCL designed and built several such devices and made important contributions to the better understanding and functioning of these devices. Our very successful superconducting ECR ion source served as a model for many high-performance ECR sources worldwide. Although ten years old, it is still in good use.

NSCL has recently built the new ARTEMIS (Advanced Room TEMperature Ion Source) ion source, that is better adapted to the new needs of the NSCL research program. For the Coupled Cyclotron Facility, very intense, medium charge state ion beams are needed instead of the low-intensity, high charge-state ion beams desired in the past. Often very expensive, isotopically enriched material must be ionized. To reduce cost, highly efficient techniques must be developed that convert as much of the material into the desired ions, with as little loss as possible.