Fragment angular distributions in the fission of heavy nuclei by 103 mev helium ions and 51.5 mev deuterons

Abstract

Abstract Fragment angular distributions in the fission of 209 Bi, 234 U, 233 U, 235 U and 238 U by 51.5 MeV deuterons and 103 MeV helium ions, including the fission of 197 Au by the latter projectiles, have been measured using solid state detectors. The c.m. angular distributions have been calculated and fitted by a series of Legendre polynomials. The W(θ)/W(90°) anisotropies of the fragments have been calculated from the polynomial series and compared with anisotropies measured with similar projectiles, but of different energy. Variational trends observed in the anisotropy with projectile, projectile energy and the fission parameter Z 2 A are qualitatively explained in terms of changes in the total angular momentum I and its projection K on the nuclear symmetry axis. Fission cross sections measured for the various reactions are compared with total reaction cross sections calculated for an optical-model potential.