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

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±0.03e ² b ². 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±0.005e ² b ² which shows no sign of the asymmetry with respect to the N = 82 shell closure exhibited by the Te isotopes.