Proton bombardment of ${\mathrm{Er}}_2$${\mathrm{O}}_3$ yielded a holmium activity with a half-life of 3.0 hours. It was found to decay by emitting two beta particles with energies of 1.0 and 0.28 Mev and with gamma rays of 0.35- and 0.70-Mev energy. It was produced by ${\mathrm{Er}}^{170}(p, \alpha ){\mathrm{Ho}}^{167}$ and ${\mathrm{Er}}^{167}(n, p){\mathrm{Ho}}^{167}$ reactions, and is assigned to ${\mathrm{Ho}}^{167}$.

• Received 12 May 1954

DOI:https://doi.org/10.1103/PhysRev.98.688