The Disintegration of Praseodymium 142

The radiations from ${\mathrm{Pr}}^{142}$ have been examined with a thin lens spectrometer. One gamma-ray was found having an energy of ${1.57}_6$ Mev. The beta-spectrum is complex, the two groups observed having maximum kinetic energies of ${2.15}_4$ Mev and ${0.63}_6$ Mev. It is suggested that the high energy beta-group gives a transition to the ground state of ${\mathrm{Nd}}^{142}$ and that the gamma-ray follows the low energy beta-transition. The half-life was found to be 19.1 hr. The electron distribution produced by bremsstrahlung, due to the absorption of the beta-rays, was observed.