Experimental survey of the production of α -decaying heavy elements in U 238 + Th 232 reactions at 7.5-6.1 MeV/nucleon

The production of α-particle decaying heavy nuclei in reactions of 7.5-6.1 MeV/nucleon U238 +Th232 was explored using an in-beam detection array composed of YAP scintillators and gas ionization chamber-Si telescopes. Comparisons of α energies and half-lives for the observed products with those of the previously known isotopes and with theoretically predicted values indicate the observation of a number of previously unreported α emitters. α-particle decay energies reaching as high as 12 MeV are observed. Many of these are expected to be from decay of previously unseen relatively neutron rich products. While the contributions of isomeric states require further exploration and specific isotope identifications need to be made, the production of heavy isotopes with quite high atomic numbers is suggested by the data.