Internal Conversion inI131

Abstract

The $\beta$-radiations from the decay of ${\mathrm{I}}^{131}$ to ${\mathrm{Xe}}^{131}$ have been investigated in a large ($\rho =50\mathrm{}$ cm) double-focusing $\beta$-ray spectrometer to determine the internal conversion coefficients for the 284-, 364-, 638-, and 724-kev $\gamma$-rays. The continuous $\beta$-spectrum is resolved into 3 components with end points of 338, 606, and 807 kev. Conclusions about the multipole character of the $\gamma$-ray transitions are made.