Fragment mass and kinetic energy distribution for the photofission ofU235andU238with 25-MeV end-point bremsstrahlung

Abstract

Fragment energy correlation measurements have been made for the photofission of $^{235}\mathrm{U}$ and $^{238}\mathrm{U}$ with 25-MeV bremsstrahlung. The correlated energies of fission fragment pairs were measured with semiconductor detectors. Distributions of kinetic energy as a function of fragment mass were deduced. The results for the isotopes $^{235}\mathrm{U}$ and $^{238}\mathrm{U}$ are compared. They are discussed in terms of fragment shell effects and also in terms of the two-mode fission hypothesis.NUCLEAR REACTIONS Fission $^{235,238}\mathrm{U}(\ensuremath{\gamma},f)$, ${E}_{\ensuremath{\gamma}max}=25$ MeV; measured fragment energies ${E}_{1}$, ${E}_{2}$; deduced $N(\ensuremath{\mu},{E}_{K})$.