Radiations ofI126

The $\beta$ and $\gamma$ radiations and the electron capture process of ${\mathrm{I}}^{126}$ have been thoroughly investigated. The ${\beta }^{-}$ branch consists of three groups of maximum energies 1.25, 0.865, and 0.385 Mev. The relative intensities of these three ${\beta }^{-}$ groups are 1:3.1:0.63 respectively. The shape of the highest energy ${\beta }^{-}$ group identifies the ground to ground transition to be a unique first forbidden one ($\Delta J=2\mathrm{}$, yes). The spectrum of the middle ${\beta }^{-}$ group as measured by the magnetic coincidence spectrometer has an allowed shape. The number of ${\beta }^{+}$ disintegrations is only 2.8 percent of that of the ${\beta }^{-}$ disintegration. Two groups of maximum energies 1.11 and 0.46 Mev were found with an intensity ratio of 3.5:1. The shape of the ${\beta }^{+}$ spectrum of the ground to ground transition is also the unique first forbidden type. The correlations among the various $\gamma$ lines and x-line and their relative intensities are determined by a selective coincidence scintillation spectrometer. In conclusion, the spin and parity of the ${\mathrm{I}}^{126}$ ground state is definitely $2^{-}$ and its decay scheme is in general agreement with that of Perlman and Welker.