Scintillation Studies of Some Neutron Deficient Isotopes of Lutecium

Abstract

${\mathrm{Lu}}^{170}$, ${\mathrm{Lu}}^{172}$, ${\mathrm{Lu}}^{173}$, and ${\mathrm{Lu}}^{174}$ activities were produced by bombarding ${\mathrm{Lu}}_2$ ${\mathrm{O}}_3$ with bremsstrahlung from the University of Illinois betatrons. Gamma rays of energy 0.083, 0.190, 0.245, and 2.04 Mev were associated with the decay of ${\mathrm{Lu}}^{170}$. A gamma-gamma coincidence experiment showed that the 2.04-Mev gamma ray was coincident with the three low-energy transitions. Gamma rays of energy 0.079, 0.113, 0.181, 0.203, 0.325, 0.370, 0.525, 0.820, 0.900, and 1.09 Mev were associated with the electron capture decay of 6.7-day ${\mathrm{Lu}}^{172}$, the isotope studied in the most detail. Levels of energy 0.0787, 0.2602, 0.3731, 0.5769, 0.9015, 1.082, and 1.99 Mev above the ground state have been assigned to ${\mathrm{Yb}}^{172}$ by gamma-gamma coincidence measurements and energy considerations. Gamma rays of energy 0.022, 0.079, 0.113, 0.145, 0.176, 0.274, 0.335, 0.440, 0.550, and 0.640 Mev were assigned to transitions between levels of ${\mathrm{Yb}}^{173}$ while gamma rays of energy 0.077, 0.084, 0.113, 0.176, 0.230, 0.275, 0.990, and 1.245 Mev were associated with the decay of ${\mathrm{Lu}}^{174}$. A summary of all gamma-gamma coincidence experiments involving ${\mathrm{Lu}}^{173}$ and ${\mathrm{Lu}}^{174}$ is included in this paper. The 0.084-Mev transition associated with the decay of ${\mathrm{Lu}}^{174}$ was interpreted to be the first excited level of ${\mathrm{Hf}}^{174}$. A rough calculation of the $K$-conversion coefficient of this transition yielded ${\alpha }_K<~2.5$.