Properties of very n-rich He isotopes

Low-energy spectra of the He-8,He-10 nuclei were investigated in the (t, p)-type reactions at small centre-of-mass angles using similar to 25AMeV beams of He-6 and He-8 nuclei. The 0(+) ground state (g.s.) of He-8 and excited states, 2(+) at 3.6-3.9MeV and (1(+)) at 5.3-5.5 MeV, were populated with cross-sections of 200, 100-250, and 90-125 mu b/sr, respectively. To account for a near-threshold anomaly observed in the He-8 spectrum the population of a 1(-) continuum (soft dipole excitation) was considered. The lowest-energy group of events in the He-10 spectrum was observed at similar to 3MeV with a cross-section of similar to 140 mu b/sr. This result is consistent with the previously reported observation of He-10 providing a new g.s. position for He-10 at about 3MeV