Physics of the high current density electron beam ion source (EBIS)

Abstract

Interest in upgrading present heavy particle accelerators has led to study of EBIS as a possible source of high Z ions, e.g., Ar+18. The present work has been motivated primarily by the results reported by CRYEBIS, which indicate that a space charge neutralized, external electron gun can achieve current densities of 105 A/cm2. Scaling relationships are developed as a basis for understanding CRYEBIS operation. The relevance of collective effects to beam equilibrium and stability is pointed out. Single electron impact ionization scaling and beam neutralization scaling indicate that higher beam voltage may be the easiest way of increasing both ionization rate and particle intensity. Consideration of radial ion confinement suggests that beam collapse to high current density may be related to the highest charge state which is energetically accessible. © 1981.