SUMMARY

This chapter first gives a survey on the history of the discovery of nuclear fission. It briefly presents the liquid-drop and shell models and their application to the fission process. The most important quantities accessible to experimental determination such as mass yields, nuclear charge distribution, prompt neutron emission, kinetic energy distribution, ternary fragment yields, angular distributions, properties of fission isomers etc. are presented as well as the instrumentation and techniques used for their measurement. The contribution concentrates on the fundamental aspects of nuclear fission. The practical aspects of nuclear fission are discussed in Chapter 4 of Volume 5.

1. INTRODUCTION

Nuclear fission has had a large impact on human life, probably larger than any other field of radiochemistry. It has truly changed the world for good or for bad. Nuclear power stations are producing electricity for billions of dollars every year, and nuclear weapons changed the military and political equilibrium between nations. Research reactors used as intense sources of neutrons through neutron diffraction have contributed immensely to the knowledge of the structure of biological molecules or to the development of new materials. Nuclear reactors are used for the mass production of radioisotopes required in medical diagnosis and therapy and in modern technology.

The study of the process of nuclear fission as such has also contributed to the fundamental knowledge of matter. A nucleus that undergoes fission has to change its shape from a round-shaped or somewhat deformed ground state...