Z=50 core stability in Sn 110 from magnetic-moment and lifetime measurements

Abstract

Background: The structure of the semimagic Sn50 isotopes were previously studied via measurements of B(E2;21+→01+) and g factors of 21+ states. The values of the B(E2;21+) in the isotopes below midshell at N = 66 show an enhancement in collectivity, contrary to predictions from shell-model calculations. Purpose: This work presents the first measurement of the 21+ and 41+ states' magnetic moments in the unstable neutron-deficient Sn110. The g factors provide complementary structure information to the interpretation of the observed B(E2) values. Methods: The Sn110 nuclei have been produced in inverse kinematics in an α-particle transfer reaction from C12 to Cd106 projectiles at 390, 400, and 410 MeV. The g factors have been measured with the transient field technique. Lifetimes have been determined from line shapes using the Doppler-shift attenuation method. Results: The g factors of the 21+ and 41+ states in Sn110 are g(21+) = +0.29(11) and g(41+) = +0.05(14), respectively. In addition, the g(41+) = +0.27(6) in Cd106 has been measured for the first time. A line-shape analysis yielded τ(110Sn;21+) = 0.81(10) ps and a lifetime of τ(110Sn;31-) = 0.25(5) ps was calculated from the fully Doppler-shifted γ line. Conclusions: No evidence has been found in Sn110 that would require excitation of protons from the closed Z=50 core.