Offline Testing of the CARIBU EBIS Charge Breeder

Abstract

In 2015 an electron beam ion source (EBIS) will be installed at the ATLAS facility to charge breed radioactive beams from the Californium Rare Isotope Breeder Upgrade (CARIBU). Currently an ECR ion source is used to charge breed CARIBU beams. The EBIS will provide beams with much less contamination and higher breeding efficiencies. In preparation for its installation at ATLAS the EBIS has been successfully commissioned offline. The EBIS was configured in the offline facility to closely mimic the conditions expected in the ATLAS installation, so commissioning results should be representative of its performance with CARIBU. The EBIS breeding efficiency was tested with pulses of 133Cs¹⁺ from a surface ionization source, and for multiple operational modes maximum breeding efficiencies greater than 25% could be achieved. After transmission losses the total efficiency of the system was 15-20%. The contaminants were expectedly very low for a UHV system with nominal pressures of ~1 – 3 x 10⁻¹⁰ Torr.