Influence of the Time-Dependent Quadrupole Interaction on the Directional Correlation of theCd111Gamma Rays

Abstract

The influence of the time-dependent quadrupole interaction in various liquid sources of ${\mathrm{In}}^{111}$ on the directional correlation of the ${\mathrm{Cd}}^{111}$ gamma rays has been investigated quantitatively. By using the technique of delayed correlation measurements the characteristic interaction (relaxation) parameters ${\lambda }_2$ have been determined for aqueous In${\mathrm{Cl}}_3$ solutions as a function of the macroscopic viscosity. These experiments revealed that ${\lambda }_2$ is not simply proportional to the macroscopic viscosity of the liquid as might be expected from simple considerations. The extranuclear interaction in indium metal sources was studied as a function of temperature. The relatively large attenuation of the ${\mathrm{Cd}}^{111}$ gamma-gamma correlation in polycrystalline indium metal was found to vanish completely upon reaching the liquid phase, a result which was confirmed by delayed correlation measurements. The "true," unperturbed, directional correlation of the ${\mathrm{Cd}}^{111}$ gamma rays was computed from these experimental data and is represented by $W\left(\Theta \right)=1-(0.180\mathrm{}\pm 0.002)P_2\left(cos\Theta \right)+(0.002\mathrm{}\pm 0.003)P_4\left(cos\Theta \right)$. This correlation is characteristic for a cascade of a mixed $M1+E2\mathrm{}$ transition, with an $\frac{E2\mathrm{}}{M1\mathrm{}}$ intensity ratio of $0.021\pm 0.002(\delta =+0.146)$ followed by a pure $E2\mathrm{}$ transition, between states of angular momentum quantum number $\frac{7}{2}$, $\frac{5}{2}$, and ½.