Coulomb excitation measurements of transition strengths in the isotopes 132, 134Sn

We describe an experiment optimized to determine the transition probabilities for excitation of the first excited 2+ state in 132Sn. The large excitation energy (4.04MeV) and consequent small excitation cross-section, together with the modest beam intensity available makes this a challenging experiment. The preliminary result is B(E2;0+ → 2+) = 0.11±0.03e2b2. The high efficiency and generalized nature of the setup enabled us to also measure the first 2+ state in the two-neutron nucleus 134Sn. We have determined a value of B(E2;0+ → 2+) = 0.029±0.005e2b2 which shows no sign of the asymmetry with respect to the N = 82 shell closure exhibited by the Te isotopes.