Anisotropic directional correlations betweenγrays andKx rays emitted from atoms with deformed nuclei

Measurements of the directional correlations between $K$ x rays following internal conversion and $\gamma$ rays in ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$ and ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$ have been made. For the cascades in ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$ the correlation coefficients are $A_{22}(K{\alpha }_1-131\mathrm{}\gamma )=-0.032\mathrm{}\pm 0.007$, $A_{44}(K{\alpha }_1-131\mathrm{}\gamma )=+0.014\mathrm{}\pm 0.008$, $A_{22}(K{\alpha }_2-131\mathrm{}\gamma )=-0.017\mathrm{}\pm 0.007$, and $A_{44}(K{\alpha }_2-131\mathrm{}\gamma )=0.012\mathrm{}\pm 0.007$. For the cascades in ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$ the correlation coefficients are $A_{22}(K{\alpha }_1-133\mathrm{}\gamma )=-0.037\mathrm{}\pm 0.012$, $A_{44}(K{\alpha }_1-133\mathrm{}\gamma )=0.022\mathrm{}\pm 0.017$, $A_{22}(K{\alpha }_2-133\mathrm{}\gamma )=-0.038\mathrm{}\pm 0.017$, and $A_{44}(K{\alpha }_2-133\mathrm{}\gamma )=0.037\mathrm{}\pm 0.029$. The anisotropic correlations in ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$ verify the existence of the effect and serve as a test case for x rays following magnetic-dipole internal conversion. The measurements in ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$ establish the second known case of this phenomenon and in addition were made with better energy resolution. This case involves several mixed nuclear transitions which result in 38% of the x rays following electric-quadrupole internal-conversion processes.