Measurement of instabilities and ion heating in an electron beam ion source

Abstract

The role of instabilities in the performance of an electron beam ion source (EBIS) has been studied experimentally. Measurements were made on the EBIS test stand at the Lawrence Berkeley Laboratory using an rf spectrum analyzer, an X-ray camera and a time-of-flight analyzer. Instabilities associated with the beam current, trapped electrons and trapped ions were identified. It was found that when the instabilities were present the effective ionization rate was reduced the radial extent of the ions was increased. These observations are consistent with the hypothesis that the ions are being heated by the instabilities.