ECRIS as ion source and charge breeder

摘要

We will recall the main characteristics of ECR ion sources and their very good property of ionization efficiency. We will start with a review of on line use of ECR ion sources for production of mono or multicharged radioactive ions, and then we will specially focus our attention on charge breeding process for multicharged ion production. Initially developed for the PLATE project from ISN Grenoble, the ECR charge breeder shows that the beam injection of a primary beam inside an ECR ion source is a very general process for beam production. We will review the latest results obtained on the ISN Grenoble test bench for the production of CW or pulsed metallic ion beams with the so called '1(+)(+), method. New results are given for CW operation where the efficiency is particularly optimized for application to multicharged radioactive ion production (for example, 3.5% for Zn1+ --> Zn9+, 4.2% for Pb3+ --> Pb24+, 5% for Rb1+, Rb15+). Different ion sources have been used to study the variation of the efficiency as a function of the energy of the 1(+) primary beam. Charge-state distributions are especially measured for Pb and Rb ions. A new mode of operation, the Electron Cyclotron Resonance Ion Trap (ECRIT) breeder/buncher, which permits the trapping and the bunching of the n(+) ion beam is demonstrated and experimentally verified. This new method shows that it is possible to modify the time structure of the injected beam, just by trapping the ions inside the plasma and reextracting them by using the 'afterglow pulsed mode'. We will finish by the presentation of the first result obtained with the first especially dedicated ECR booster developed at the ISN and called PHOENIX. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 4]