Radioactive Isotopes of the Rare Earths. I. Experimental Techniques and Thulium Isotopes

The experimental techniques used in the chemical separation and identification of radioactive isotopes of the rare earth elements are described. The isotopes are produced by bombardment of rare earth oxides with α-particles, deuterons, and protons from the 60-inch Crocker Laboratory cyclotron, and also by bombardment of tantalum with 200 Mev deuterons from the 184-inch cyclotron. The production and properties of three new thulium isotopes are described.