- Gade, A;
- Janssens, RVF;
- Bazin, D;
- Broda, R;
- Brown, BA;
- Campbell, CM;
- Carpenter, MP;
- Cook, JM;
- Deacon, AN;
- Dinca, D-C;
- Fornal, B;
- Freeman, SJ;
- Glasmacher, T;
- Hansen, PG;
- Kay, BP;
- Mantica, PF;
- Mueller, WF;
- Terry, JR;
- Tostevin, JA;
- Zhu, S
The two-proton knockout reaction Be9(Ti54,Ca52+γ) has been studied at 72 MeV/nucleon. Besides the strong feeding of the Ca52 ground state, the only other sizeable cross section proceeds to a 3- level at 3.9 MeV. There is no measurable direct yield to the first excited 2+ state at 2.6 MeV. The results illustrate the potential of such direct reactions for exploring cross-shell proton excitations in neutron-rich nuclei and confirms the doubly-magic nature of Ca52. © 2006 The American Physical Society.