Study of 0+ excitations in Gd158 with the (n,n'γ) reaction

We have examined Gd158 with the (n,n'γ) reaction at neutron energies up to 3.3 MeV to determine the collective character of 0+ excitations revealed in previous Gd160(p, t) reaction studies. Moderately large B(E2;0+→21+) values are observed for transitions from some of the 0+ states lying above the pairing gap. From its excitation energy and decay properties, the 0+ excitation at 2276.7 keV is suggested as exhibiting two-phonon γγ strength. The high density of levels at similar excitation energies makes the identification of the other two-phonon states improbable. © 2007 The American Physical Society.