New Measurements for ⁸He Excited States

Breakup reactions of the double borromean nucleus ⁸He were measured at 82.3 MeV/u on CH₂ and C targets. The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment. The relative energy spectrum for ⁸He was reconstructed with good statistics. The spectrum exhibits a structure of two resonant peaks, one at an excitation energy of about 3.0 and the other at about 4.14 MeV, respectively. Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.