Thulium, in the form of Tm203, has been made radioactive by neutron irradiation In a pile. The radiations have been investigated by a magnetic beta-spectrometer and by absorption methods. A conversion line is found at an energy of 0.0682 +/- .0011 Mev. and indicates a gamma ray of 0.129 +/- .003 Mev. The beta spectrum is found to be complex as the result of a Kurie plot with apparently three components whose end points are 0.953 +/- .020 Mev., O.526 +/- .020 Mev., and 0.30U +/- .020 Mev. The intensities are, respectively, 74%, 18%, and 8% as Judged by the graphical integration of the areas under the components. The existence of these components and the values of the end points are subject to confirmation by gamma ray and coincidence measurements. As the result of absorption measurements of the gamma rays in lead it is believed that the gamma radiation consists of three components with energies about 0.1 Mev., 0.2 Mev. and 0.8 Mev. respectively.[...]

Foster, J. (Supervisor)