The helium ion-induced fission of enriched isotopes of mercury and tungsten at moderate bombarding energies

Abstract

This represents the final experimental results of a series of investigations over the past 12 years concerning the charged particle induced fission of isotopes below polonium on the periodic chart. Again, as before, the bombarding particles were 41 and 65 MeV helium and the targets in this case were enriched isotopes of mercury and tungsten. The total fission cross sections (σ f ) for the mercury isotopes 198, 199, 200, 201, 202 and 204 at the bombarding energy of 41 MeV were 265, 315, 365, 164, 85.7 and 73.1 microbarns (μ b) respectively. A single determination of the fission cross sections at 65 MeV for 198Hg and 199Hg were 37,800 and 25,200 μ b respectively. These results as well as the widths at half maximum (W 1/2) of the fission fragment mass distribution curve were consistent with the previous trends and were approx. 20 a.m.u.±1 a.m.u. The values of the ρ f of the 41 MeV helium ion-induced fission of isotopes 182, 183, 184 and 186 of tungsten were estimated to be 0.56, 0.90, 0.47 and 0.27 μ b respectively.