Neutron Induced Radioactivity in Certain Rare-Earth Elements

Abstract

By activating specimens of lanthanum, neodymium, samarium, europium, gadolinium, and terbium in the Oak Ridge pile for a particularly long exposure, several hitherto unobserved radioactivities are found. Determinations are made of the half-lives and of the beta- and gamma-energies by absorption and spectrometric methods. Lanthanum and neodymium were the only elements showing no internal conversion lines. Terbium appears as a contaminant in its neighboring elements by virtue of its very large cross section for neutron capture. Terbium and europium show complex beta-spectra, and each has many conversion electron lines.