Abstract
The 1i(13/2) -> 1h(9/2) (M2) and 3s(1/2) -> 2f(7/2) (E3) reduced proton transition probabilities in Bi-209(83) have been determined from the direct half-life measurements of the 13/2(1)(+) and 1/2(1)(+) states using the Romanian array for gamma-ray SPectroscopy in HEavy ion REactions (RoSPHERE). The 13/2(1)(+) and 1/2(1)(+) states were found to have T-1/2 = 0.120(15) ns and T-1/2 = 9.02(24) ns respectively. Angular distribution measurements were used to determine an E3/M2 mixing ratio of delta = -0.184(13) for the 1609 keV gamma-ray transition deexciting the 13/2(1)(+) state. This value for delta was combined with the measured half-life to give reduced transition probabilities of B(E3, 13/2(1)(+) -> 9/2(1)(-)) = 12(2) x 10(3) e(2) fm(6) and B(M2, 13/2(1)(+) -> 9/2(1)(-)) = 38(5)mu(2)(N) fm(2). These values are in good agreement with calculations within the finite Fermi system. The extracted value of B(E3, 1/2(1)(+) -> 7/2(1)(-)) = 6.3(2) x 10(3) e(2) fm(6) can be explained by a small (similar to 6%) admixture in the wave function of the 1/2(1)(+) state.