Perturbation of the (1063.62-569.67) keV gamma-gamma directional correlation inPb207

Abstract

..gamma..-..gamma.. directional correlation studies have been carried out on the (1063.62-569.67) keV 13/2/sup +/ /sup M//sup 4 +//sup E//sup 5/ 5/2/sup -/ /sup E//sup 2/ 1/2/sup -/ cascade in the decay of /sup 207/Bi using the time differential perturbed angular correlation method. The measurements show time dependent magnetic perturbation of the correlation. From the plot of A/sub 2/(t-bar) vs t-bar (finite time resolution corrected), the value of the relaxation parameter lambda/sub 2/ and the unperturbed A/sub 2/(0) coefficient (solid angle corrected) obtained are (2.4 +- 0.3) x 10/sup 9/ sec/sup -1/ and 0.259 +- 0.016, respectively. From the plot of A/sub 0/(t) vs t, the unperturbed value of T/sub 1///sub 2/ and therefrom lambda/sub 0/ for the 569.67 keV level are determined to be (130.7 +- 1.3) ps and (5.30 +- 0.06) x 10/sup 9/ sec/sup -1/, respectively. Using the lambda/sub 0/ and lambda/sub 2/ values, the integral attenuation coefficient G-bar/sub 2/(infinity) has been estimated to be 0.69 +- 0.03. The differential data at various angles were integrated and the solid angle corrected A/sub 2/(infinity) coefficient thus obtained is 0.204 +- 0.005. The perturbation mechanism is discussed in the light of the spin-spin interactions between the 6s electrons of themore » neighboring paramagnetic Pb/sup + + +/ ions. The results are found to be consistent with the theory of Abragam and Pound.« less