Developments in high-intensity two-step target design

Abstract The two-step fission-product target concept is analyzed to design a prototype target for testing at the ISAC facility. A two-step target consists of an inner cylinder of heavy metal irradiated by an energetic light ion beam; neutrons produced emerge from the target into a coaxial secondary target (blanket) of fissionable material. With this approach, the production of fission product activities is enhanced compared to other products that can interfere in experiments, and significantly less energy is deposited in the secondary target than for direct irradiation. The design is mechanically simple and provides independent control of operating temperatures. The analysis determined appropriate target and blanket dimensions, and energy deposition profiles, temperature distributions and fission production rates. The production rates of some neutron-rich isotopes for selected elements are summarized. A conceptual design is presented, along with issues on cooling the primary target and heating of the secondary target.