Second Generation Degrader Foil for the CARIBU Project

The Californium Rare Ion Breeder Upgrade (CARIBU) project utilizes 252Cf to provide beams of neutron-rich nuclides with intensities not currently available at other facilities. The electroplated 252Cf source is positioned inside a large helium gas catcher, where the ejected fission fragments lose their energy and are slowed. Prior to entering this gas catcher, the ions first pass through a gold cover foil to contain self-sputtering recoil emissions and then through an aluminium degrader foil, where much of their residual energy is reduced. In the past due to production limitations, a less than ideal cylindrical shaped degrader was utilized. This resulted in non-uniform energy loss as the ions passed through the degrader. With the advent of 3D printing, a new hemispherical degrader was prepared to enable a more uniform energy loss. The design, production, and assembly will be discussed.