Off-line commissioning of EBIS and plans for its integration into ATLAS and CARIBU.

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed at Argonne to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne Tandem Linac Accelerator System (ATLAS). The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and significantly improve the purity of reaccelerated radioactive ion beams. The CARIBU EBIS-CB has been successfully commissioned offline with an external singly charged cesium ion source. The performance of the EBIS fully meets the specifications to breed rare isotope beams delivered from CARIBU. The EBIS is being relocated and integrated into ATLAS and CARIBU. A long electrostatic beam transport system including two 180° bends in the vertical plane has been designed. The commissioning of the EBIS and the beam transport system in their permanent location will start at the end of this year.

Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source.

The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz.

EBIS charge breeder for CARIBU.

A high-efficiency charge breeder based on an Electron Beam Ion Source (EBIS) is being developed by the ANL Physics Division to increase the intensity and improve the purity of accelerated radioactive ion beams. A wide variety of low-energy neutron-rich ion beams are produced by the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne Tandem Linac Accelerator System (ATLAS). These beams will be charge-bred by an EBIS charge breeder to a charge-to-mass ratio (q/A) ≥ 1/7 and accelerated by ATLAS to energies of about 10 MeV/u. The assembly of the CARIBU EBIS charge breeder except the injection/extraction beam lines has been completed. This summer we started electron beam commissioning of the EBIS. The first results on electron beam extraction, transport from the electron gun to a high power electron collector are presented and discussed.