The mechanism of the reaction ¹²C(n, ń)3α at 14.18 MeV neutron energy

A detailed study in photoemulsions of the reaction ¹²C(n, ń)3α excited by neutrons of energy 14.18 ± 0.05 MeV has provided information on the reaction mechanism. About 50% of the events are attributed to the mode ¹²C(n, ń)¹²C*, ¹²C*(α)⁸Be* -> 2α, most of the remainder being due to ¹²C(n, α)⁹Be*, ⁹Be*(n)⁸Be* -> 2α and ⁹Be*(α)⁵He*(n)α. However, the reaction ¹²C(n, ⁵He*)⁸Be* cannot be excluded. Four-body break-up, suggested by some authors, is unnecessary to explain the results. The 10.8 and 11.8 MeV states of ¹²C occur in the (n, ń) reaction and the data allow the assignment 1^- to the former and suggest 2^- for the latter.