|
|
|
 |
History : Hall of Fame : James Chadwick
|
James Chadwick (1891 - 1974)
In 1913 he received his master's degree from the University of Manchester and left for Germany to work with Hans Geiger. There, Chadwick was the first to show that beta particles possess a range of energies up to some maximum value. After WWI, Chadwick returned to England and joined forces with Ernest Rutherford. Intrigued by Rutherford's speculation about a subatomic particle with no charge, Chadwick began a series of experiments to demonstrate the existence of such a particle. Initially, none of the experiments succeeded. Then, in 1930, Walther Bothe and Herbert Becker described an unusual type of gamma ray produced by bombarding the metal beryllium with alpha particles. Chadwick recognized that the properties of this radiation were more consistent with what would be expected from Rutherford's neutral particle. When Frédéric and Irène Joliot-Curie subsequently claimed that Bothe and Becker's "gamma rays" could eject high energy protons from paraffin, Chadwick knew these were not gamma rays. The subsequent experiments by which Chadwick proved the existence of the neutron earned him the 1935 Nobel Prize in physics. Not only did this singular particle provide physicists with a superlative tool for investigating the atom, it was also used to produce a wide variety of new radioisotopes and permitted the initiation of nuclear chain reactions. Hans Bethe has referred to Chadwick's discovery as the historical beginning of nuclear physics.
|
|
