Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion

Abstract

A role of the unstable nuclei 6 Be, 8 Be and 9 B in the dissociation of relativistic nuclei 7,9 Be, 10 B and 10,11 C is under study on the basis of nuclear track emulsion exposed to secondary beams of the JINR Nuclotron. Contribution of the configuration 6 Be + n to the 7 Be nucleus structure is 8 ± 1% which is near the value for the configuration 6 Li + p . Distributions over the opening angle of α-particle pairs indicate to a simultaneous presence of virtual 8 Be g.s . and 8 Be 2+ states in the ground states of the 9 Be and 10 C nuclei. The core 9 B is manifested in the 10 C nucleus with a probability of 30 ± 4%. Selection of the 10 C “white” stars accompanied by 8 Be g.s . ( 9 B) leads to appearance in the excitation energy distribution of 2α2 p “quartets” of the distinct peak with a maximum at 4.1 ± 0.3 MeV. 8 Be g.s . decays are presented in 24 ± 7% of 2He + 2H events of the 11 C coherent dissociation and 27 ± 11% of the 3He ones. The channel 9 B + H amounts 14 ± 3%. The 8 B g.s . nucleus is manifested in the coherent dissociation 10 B → 2He + H with a probability of 25 ± 5% including 13 ± 3% of 9 B decays. A probability ratio of the mirror channels 9 B + n and 9 Be + p is estimated to be 10 ± 1.