Speaker
Description
Excited states of $^{130}$Sn, the even-even neighbour of doubly-magic $^{132}$Sn, were populated through safe Coulomb excitation using the recently commissioned, highly efficient MINIBALL array. The $^{130}$Sn ions were accelerated to 4.4 MeV/u at the HIE-ISOLDE accelerator and collided with a $^{206}$Pb target. Deexciting $\gamma$ rays from the excited states of both the target and projectile nuclei were detected in coincidence with scattered particles. In addition to $\gamma$ rays from the first 2$^+$ state, deexcitation from higher-lying states was observed, attributed to an isomeric $^{130}$Sn$_{7-}$ beam component. Reduced transition strengths for the 0$^+_{\mathrm{g.s.}}$ → 2$^+_1$ transition will provide insights into the evolution of collectivity and nuclear structure around the magic shell closure in 132Sn. Advanced shell model calculations using realistic interactions predict enhanced collectivity in the neighbouring isotopes of $^{132}$Sn [1]. Additionally, a discrepancy between previous measurements of $^{130}$Sn and recent theoretical results remains to be resolved [2]. These calculations also indicate a transition from a slightly oblate to a prolate configuration of the first excited 2$^+$ state across doubly magic $^{132}$Sn. The high statistics of the performed experiment will further enable an experimental investigation of the quadrupole moment of the 2$^+$ state in $^{130}$Sn.
[1] D. Rosiak et al. Phys. Rev. Lett. 121, 252501 (2018)
[2] T. Togashi et al. Phys. Rev. Lett. 121, 062501 (2018)
Supported by the German BMBF 05P21PKFN9 and 05P21RDCI2 and European Union’s Horizon Europe Framework research and innovation programme under grant agreement no. 101057511
