Some Evidence for Admixture of Magnetic Quadrupole Radiation in Atomic X-Ray Transitions from Measurements of Angular Correlation of X Rays

Angular correlations between $K$ and $L$ x rays in Pb were measured. The angular correlation functions for the $K-L_{\alpha }$ and $K-L_{\beta }$ cascades were found to be $W\left(\theta \right)=1+(4.13\mathrm{}\pm 0.36)\times {10}^{-2\mathrm{}}{P}_2\left(cos\theta \right)$ and $W\left(\theta \right)=1+(1.22\mathrm{}\pm 0.42)\times {10}^{-2\mathrm{}}{P}_2\left(cos\theta \right)$, respectively. These results are in relatively good agreement with theoretical predictions only when the small admixtures of magnetic quadrupole radiation in the x-ray transitions are taken into account.