Neutral injection for radioactive ion beams and accelerator mass spectrometry

Abstract

Neutral Injection was first used forty years ago for the acceleration of He ions by tandem accelerators, before the advent of the negative He ion source. Later, almost universal sputter-negative-ion sources were developed and the use of neutral injection fell into disuse for nuclear physics with tandem accelerators. With the advent of Accelerator Mass Spectrometry (AMS) in 1977 the idea of neutral injection was revived briefly. Now that AMS has matured and Radioactive Ion Beam (RIB) acceleration is being undertaken for nuclear physics, we propose the revival of a modern form of Neutral Injection. The use of resonant electron transfer for neutralization is discussed, as is the scattering degradation of the ion beam during neutralization and re-ionization. We show that the process is suitable for some types of AMS and the acceleration for RIB of positive ions, that form negative ions with difficulty, to a few MeV.