Decay ofI130→Xe130

Abstract

The decay of ${\mathrm{I}}^{130}$ has been previously studied by two groups of workers, and, as a result, the following level scheme for ${\mathrm{Xe}}^{130}$ has been proposed: 528 kev ($2^{+}$), 1190 kev ($4^{+}$), 1930 kev ($6^{+}$), and 2340 kev ($5^{-}$). Only the states at 1930 kev and 2340 kev were found to be directly populated by beta decay. However, the recent measurement of spin 5 for ${\mathrm{I}}^{130}$ suggests that the 1190-kev state, if $4^{+}$, should be populated by beta decay. In the present work, such a group was looked for and not found. A lower limit of 9.8 was set for the $log\mathrm{ft}$. Gamma-gamma correlations were also measured. The experimental correlation for 1190-528-0 level sequence can be fitted by $4\left(Q\right)2\left(Q\right)0$ or by $2(96\%D+4\%Q)2\left(Q\right)0$ sequences. The $2^{+}$ assignment to the 1190-kev level requires a predominantly $M1\mathrm{}$ transition for the $2^{+}$ to $2^{+}$ transition in contrast to the predominantly $E2\mathrm{}$ character of other known transitions of this type. Therefore, either $4^{+}$ or $2^{+}$ assignment to the 1190-kev state leads to an anomalous situation. Six other angular correlations were measured in an attempt to determine the characteristics of the levels at 1930 kev and 2340 kev. It was not possible to obtain unique assignments.