NUCLEAR ENERGETICS AND -ACTIVITY*

Abstract

EVER since the discovery by Joliot and Curie of the phenomenon of induced radioactivity in 1934, a very large number of radioactive nuclei, exceeding 450, has been prepared in the laboratory. In recent years, new types of radioactive nuclei have been obtained from fission of heavy nuclei like ⁹²U, ⁹⁰Th and ⁹¹Pa, and possibly also of ⁹³Np and ⁹⁴Pu ; which have, however, not yet been released for publication. Extensive studies of the ?˜ and ?+ activities of these nuclei have been made in the various laboratories of the world. The data so far collected, though they have reached vast magnitudes, are by no means sufficient, but already they form a rather bewildering mass (for example, see tables by Seaborg¹), reminding one of the vast collection of spectroscopical data, before the rise of the modern theories of the electron-structure of the atom reduced them to a few simple laws like Pauli's exclusion principle.