Inelastic proton scattering on the neutron rich Cr isotopes

Inelastic proton scattering on the neutron rich Cr isotopes at around $N=40$ has been investigated. Spectroscopy of these nuclei is of great importance because of the strong deformation suggested by the low excitation energies of the first 2$^{+}$ states in $^{60,62}$Cr [1]. In the present work, the structures of the neutron rich Cr isotopes were studied by measuring the excitation energies and the (p,p$'$) cross sections to these states. The experiment was performed at RIPS in RIKEN. The Cr isotopes were produced by the fragmentation of 63MeV/nucleon $^{70}$Zn and were excited by bombarding a liquid hydrogen target. De-excitation $\gamma$ rays were detected by the NaI(Tl) array DALI2 in coincidence with the scattered particles. A time of flight spectrometer is newly developed to greatly improve the particle identification resolution %and acceptance for the scattered particles. With the cross sections to the first excited states derived from the $\gamma$-ray spectra, the structure of the neutron rich Cr isotopes will be discussed. \\ {\bf Reference:} 1. O. Sorlin et al., Eur. Phys. J. A {\bf 16}, 55-61 (2003).