Interaction of Neutrons with Matter

As mentioned several times previously (Chapter 2), the neutrons are the basic parti­cles of nuclei. They can be present as free neutrons as a result of neutron decay (see Section 4.4), but it is a very rare phenomenon. Neutrons, however, can be pro­duced by nuclear reactions (Chapter 6) and can be widely used in different scien­tific and practical applications. Thus, in this chapter, the basic concepts of the interactions of neutrons with matter will be discussed.