Henry Becquerel, Pierre and Marie Curie and radioactivity: background, circumstances and implication of the founder discoveries

After Roentgen's X-rays discovery in 1895, Henry Becquerel discovers a proper radiation of uranium. Then, Pierre and Marie Curie discover polonium and radium. They establish that some atoms may produce spontaneously energy under radiations form which may lead to induce radioactivity. The essential interpretation was done by Rutherford with the distinction of alpha, beta and gamma radiations, and the atomic model of Rutherford-Bohr. The first transmutations under radiations effects lead to the neutrons discovery by Bothe and Becker, Irene Curie and Frederic Joliot, and to the interpretation by Chadwick, the artificial radioactivity of phosphorous by I. Curie and F. Joliot, and to the fission. (A.B.). 7 photos