Argonne National Laboratory

Californium Rare Isotope Breeder Upgrade (CARIBU)

Californium Rare Isotope Breeder Upgrade (CARIBU)

CARIBU provides beams of californium-252 fission fragments — neutron-rich isotopes far from stability — for experimenters. The facility allows for fast, efficient and essential chemistry-free extraction of fission fragments. CARIBU uses a gas catcher and various isotope separation techniques to provide low-energy beams for mass measurements, beta decay or laser manipulation, or for injection into the ATLAS accelerator following charge breeding.

The study of neutron-rich radioactive nuclei is of significant interest in nuclear-structure physics, where knowledge of how structural properties evolve with neutron excess can shed light on fundamental features of the interaction between nucleons and the shapes of nuclei.

In nuclear astrophysics, the masses, decay rates, decay modes and Q values of nuclei produced in stellar environments is key to understanding the origin of elements. CARIBU was designed to give experimenters access to some of these nuclei by catching fission fragments of californium-252 and making them available as low-energy beams or for charge breeding to use in ATLAS.

The low-energy beams produced by CARIBU can be sent to the Canadian Penning Trap for high precision measurements of masses of very neutron-rich nuclei.

Near CARIBU, a new low-background, low-energy beam area is being built to accommodate beta decay tape stations and laser spectroscopy set-ups.

Additionally, a new EBIS ion source has been developed to efficiently charge breed the CARIBU beams to make them suitable for acceleration through ATLAS. This makes it possible to study a large variety of phenomena from Coulomb excitation to transfer reactions.