ABSTRACT
With mendelevium, element synthesis using helium-ion beams and reactorgenerated actinide targets came to an end. In order to proceed to element 102, one would need fermium targets which cannot be made. To go beyond element 101, projectiles able to add more than two protons in a fusion reaction were required, necessitating ions heavier than helium. Such beams became available in 1957 at the HILAC (Heavy Ion Linear Accelerator) in Berkeley and in 1960 at the U-300 heavy-ion cyclotron of the Joint Institute for Nuclear Research (JINR) in Dubna, north of Moscow.
