ABSTRACT
In 1920, Rutherford postulated that there were neutral, massive particles in the nucleus of atoms. James Chadwick, a colleague of Rutherford, discovered the neutron in 1932. He bombarded a beryllium target with alpha particles producing neutrons that recoiled into a block of paran. Chadwick’s apparatus, the rst neutron generator (NG), is schematically described in Figure 3.1.
