TABLE OF CONTENTS Studies of properties of nuclei and of the nuclear force have contributed significantly to the formulation of the fundamental laws of nature. The understanding of physical laws has in the past led to applications that have benefited mankind. For example, the principles of electromagnetism led to the commercialization of electricity, which has proven indispensable in our daily life. Similarly, the explanation of atomic phenomena has given us the laser, the transistor and a host of amazing devices. Needless to say, many applications have also arisen from our understanding of nuclear physics. However, because these developments have been put to both constructive as well as destructive use, they have often led to controversy. In this chapter, we will describe only a few of these applications and the principles behind them.
Neutrons, being electrically neutral, do not sense the direct Coulomb force. As a consequence, unlike protons that are repulsed by the nuclear charge, low energy neutrons can get quite close to the nuclei and interact with them through the attractive nuclear potential to form bound states. In the early days of nuclear physics, the capture of low energy neutrons within nuclei was promoted as a technique for producing new nuclei of higher A values. In experiments designed to make transuranic elements through neutron capture, it was often observed that scattering of low energy thermal neutrons (at room temperature T ?300 K, kT ?1/40 eV) from odd- A nuclei such as 235
