Decay of 20-MinuteAg115

Abstract

A study of radiations from decay of 20-min ${\mathrm{Ag}}^{115}$ has led to determination of the maximum beta energy as 3.2±0.1 MeV and measurement of intensities of some eighteen $\gamma$ rays ranging in energy from 0.13 to 2.50 MeV. Measurements via $\beta -\gamma$ and $\gamma -\gamma$ coincidence spectrometry and via Hoogenboom sum-coincidence spectrometry allowed construction of a tentative decay scheme. This scheme uses the ground state and seven excited levels of ${\mathrm{Cd}}^{115}$ also known from other studies via the ${\mathrm{Cd}}^{114}(d, p)$ reaction. It is concluded that the 20-min ${\mathrm{Ag}}^{115}$ has spin and parity ½-, with about half of the $\beta$ decays being allowed transitions to states of spins and parities ½- or $\frac{3}{2}-$ at 2.12 and 2.50 MeV, the remainder being first-forbidden transitions to the ground-state and low-lying ½+ and $\frac{3}{2}+$ levels. No evidence was found for radiations associated with branching to 43-day ${\mathrm{Cd}}^{115}$ ($\frac{11}{2}-$).