when did the development of nuclear science begin
History of nuclear weapons In the first decades of the 20th century, physics was revolutionised with developments in the understanding of the nature of atoms. In 1898, Pierre and Marie Curie discovered that pitchblende, an ore of uranium, contained a substance—which they named radium—that emitted large amounts of radioactivity. Ernest Rutherford and Frederick Soddy identified that atoms were breaking down and turning into different elements. Hopes were raised among scientists and laymen that the elements around us could contain tremendous amounts of unseen energy, waiting to be harnessed.
Dayton Project At Los Alamos, physicist Robert Serber proposed that instead of relying on spontaneous fission, the chain reaction inside the atomic bomb should be triggered by a neutron initiator. The best-known neutron sources were radium-beryllium and polonium-beryllium. The latter was chosen, as polonium has a 138-day half-life, which made it intense enough to be useful but not long-lived enough to be stockpiled. Thomas took charge of the development of techniques to industrially refine polonium for use with beryllium in the "urchin" internal neutron initiators. This effort became the Dayton Project.[6][7]