Theoretical and experimental studies of the neutron rich fission product yields at intermediate energies

¹ Department of Physics, P.O. Box 35 (YFL), FI-40014 University of Jyväskylä, Finland
² V.G. Khlopin Radium Institute, 194021, St. Petersburg, Russia

^a e-mail: rubchen@phys.jyu.fi

Abstract

A new method to measure the fission product independent yields employing the ion guide technique and a Penning trap as a precision mass filter, which allows an unambiguous identification of the nuclides is presented. The method was used to determine the independent yields in the proton-induced fission of ²³²Th and ²³⁸U at 25 MeV. The data were analyzed with the consistent model for description of the fission product formation cross section at the projectile energies up to 100 MeV. Pre-compound nucleon emission is described with the two-component exciton model using Monte Carlo method. Decay of excited compound nuclei is treated within time-dependent statistical model with inclusion of the nuclear friction effect. The charge distribution of the primary fragment isobaric chain was considered as a result of frozen quantal fluctuations of the isovector nuclear density. The theoretical predictions of the independent fission product cross sections are used for normalization of the measured fission product isotopic distributions.