Measurement of the fission moment of inertia of medium mass nuclides

Measurements have been made, by means of mica nuclear track detectors, of the distributions in tracklength and the angular distributions with respect to the beam direction for the fission fragments from the systems Ag, Te and Au plus 80-MeV alpha particles. Analysis of the tracklength distributions indicated that, in each case, full momentum transfer from the incident projectile characterized those interactions that led to fission. Angular-momentum dependent statistical model calculations for the decay of the respective compound nuclei then provided information on fission-evaporation competition in the de-excitation processes, and in particular the distribution in nuclear temperature and angular momentum at which the fission events took place. This information was then employed in the analysis of the measured fission fragment angular distributions, and to extractK ₀ ² values. From these, the moments of inertia of the fission saddle point shapes were calculated, and the results are in good agreement with theoretical estimates.