Unbound states studied by direct reactions

The t(⁶He,⁸He)p t(⁸He,¹⁰He)p reactions were studied in experiments with 25A MeV ⁶He beam and 27.4A MeV ⁸He beams and an unique tritium gas target. Results on the ⁸He and ¹⁰He excitation energy spectra are presented. The ⁸He spectrum exhibits 3 states, apart of the ground state and known (2⁺) state at 3.6 MeV, the third state is seen at 5.4 MeV. A tentative assignment 1⁺ is proposed for this structure. The ¹⁰He spectrum shows no event at the excitation energy below 3 MeV what is in contradiction with the earlier reports on this nucleus. A high statistics of α-n coincidence events collected for the ⁸He beam run has been subjected to analysis in order search for the bound tetraneutron. The search produced a negative result.