Experiments related to Possible Production of Superheavy Elements by Proton Irradiation

Abstract

MARINOV et al. have reported results which led them to believe that they might have found element 112, which they took to be a mercury homologue, produced by secondary reactions occurring in the irradiation of tungsten targets with 24 GeV protons¹. Evidence was presented for alpha and spontaneous fission decay associated with a species having chemical properties similar to those of mercury and a half-life of the order of months at least. As a possible mechanism for the synthesis of 112, they discussed the production, by proton scattering, of heavy recoil nuclei having kinetic energies exceeding the Coulomb barrier for their reaction with other tungsten nuclei in the target. With the assumptions that such recoils are produced with a cross section of about 1 µbarn and that they react to form the spontaneously fissioning species with a cross section about 10 µbarns, they estimated that in the 120 g cm⁻² target, irradiated by 10¹⁸ protons, the yield could have been 10³ superheavy atoms.