Rouhollah (Kouroush) Gheisari

The purpose of this thesis, is estimation of fission time of heavy nuclei like 233Pa and 239Np in the framework of statistical model with two classes of excited states in the first and the second potential wells. At first, we define fission barrier in the framework of drop model and then estimate the shape of the double-humped fission barrier by considering for shell effects. We investigate decay of heavy nuclei in the framework statistical model by using a computer program and estimate the fission time of heavy nuclei 233Pa and 239Np during the transition from the first potential well to scission point. Finally, we indicate that the shell model, will affect some of nuclear characteristics such as the effect of fission time enhancement.