E2/M1 Mixing Ratios for Gamma Transitions in ¹⁵¹Sm

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Measurements of gamma-gamma angular correlations in ¹⁵¹Sm following the decay of ¹⁵¹Pm have been made. A dual parameter (4096 ch.×4096 ch.) coincidence method with two Ge(Li) detectors was used. Multipole mixing ratios (E2/M1) of 17 gamma rays were deduced. Among them, six mixing ratios were determined for the first time. The parity of the 663.4 keV and 773.8 keV levels was assigned to be negative. Experimental large absolute values of E2/M1 mixing ratios of δ_349.8=2.46±_0.91^1.43, δ_597.7=−4.30±_19.4^2.74, δ_636.1=−3.41±_0.32^0.29 and δ_669.2=−69.3±_∞^58.9 agree with a calculation which takes vibrational components into account.