Levels inRh101Populated by the Decay ofPd101

Abstract

The decay of 8.4-h ${\mathrm{Pd}}^{101}$ has been investigated using high-resolution gamma-ray and conversion-electron spectroscopy. Strong $K$, $L$, and $M$ conversion lines of a 157.32±0.03-keV transition converted in rhodium are observed to grow in initially pure ${\mathrm{Pd}}^{101}$ sources and ultimately to decay with a half-life of 4.43±0.06 days. This isomeric transition is classified as $M4\mathrm{}$ on the basis of its radiative lifetime of (1.3±0.3)×${10}^8$ sec. Other transitions attributed to ${\mathrm{Pd}}^{101}$ decay have been observed with energies 24.46, 269.60, 296.13, 320.7, 453.2, 565.5, 590.3, 723.4, 748.3, 992.6, 1177.2, 1202.1, 1218.6, 1289.3, and 1312.8 keV. Energy-sum relationships and coincidence studies reveal levels in ${\mathrm{Rh}}^{101}$ with the following energies, spins, and inferred parities: 0 (½-), 157.32 ($\frac{9}{2}+$), 181.78 ($\frac{7}{2}+$), 477.9 ($\frac{5}{2}+$), 747.5 ($\frac{7}{2}+$), 905.3 (+), 1359.2 (+), and 1470.6 (+) keV. The ground-state spin and parity $\frac{5}{2}+$ is suggested for ${\mathrm{Pd}}^{101}$. A comparison is made between the energy levels of ${\mathrm{Rh}}^{101}$ as found in this investigation and the properties of low-lying levels reported for neighboring nuclei. The existence of additional collective states in ${\mathrm{Rh}}^{101}$ is suggested.