E3 and M2 transition strengths in Bi 83209

The 1i132›1h92(M2) and 3s12›2f72(E3) reduced proton transition probabilities in Bi83209 have been determined from the direct half-life measurements of the 1321+ and 121+ states using the Romanian array for ?-ray SPectroscopy in HEavy ion REactions (RoSPHERE). The 1321+ and 121+ states were found to have T12=0.120(15) ns and T12=9.02(24) ns respectively. Angular distribution measurements were used to determine an E3/M2 mixing ratio of ?=-0.184(13) for the 1609 keV ?-ray transition deexciting the 1321+ state. This value for ? was combined with the measured half-life to give reduced transition probabilities of B(E3,1321+›921-)=12(2)×103e2fm6 and B(M2,1321+›921-)=38(5)µN2fm2. These values are in good agreement with calculations within the finite Fermi system. The extracted value of B(E3,121+›721-)=6.3(2)×103e2fm6 can be explained by a small (~6%) admixture in the wave function of the 121+ state. © 2016 American Physical Society.