In-beam gamma-ray spectroscopy of F and Ne isotopes near the island of inversion

 It is known that neutron magic number N=20 disappears in the region of Z=10~12. Study of nuclei in this region, called "island of inversion”, is important for understanding the evolution of shell structure in the neutron-rich region. Currently the south boundary of the island of inversion is not known because available experimental data on neutron-rich F and Ne is not sufficient.

 We performed in-beam gamma-ray spectroscopy of ²⁹F, ^28-30Ne at the RIKEN RI Beam Factory. Secondary beams of ²⁹F, ^29,30Ne (~230MeV/u), generated by projectile fragmentation of a ⁴⁸Ca primary beam on a beryllium target, were impinged on 15cm thick liquid-hydrogen target provided by MINOS. The de-excitation gamma rays were detected with the NaI(Tl) scintillator array DALI2. Outgoing particles were identified by the SAMURAI spectrometer.

 We investigated high-lying excited states based on gamma-gamma coincidence analysis. In case of nucleon-removal reactions of ^29,30Ne and ³⁰Na partial cross sections have also been investigated. In this presentation, we discuss the nuclear structure of these nuclei.

This work was done with SAMURAI 21 collaboration.