Nuclear physics in Rutherford’s laboratory before the discovery of the neutron

Abstract

Work by Rutherford and his colleagues led to his nuclear model of the atom (1911), although it took a few years more for him to recognize the significance of this insight. With the understanding that radioactivity is a nuclear phenomenon, one may say that nuclear physics became the major pursuit in Rutherford’s Manchester and Cambridge laboratories. The key to this problem was reported in his 1919 papers on transmutations produced by bombarding nitrogen with alpha particles. Soon, a number of other elements yielded to these projectiles of radioactive decay, but recognition that more energetic particles would be needed to disintegrate heavier elements led to the development of accelerating machines. The search for the neutron, cloud chamber photographs of disintegrations, and exploration of the properties of beta and gamma rays also figured greatly in Rutherford’s attack on the nucleus.