Study of 14N(γ,np)3α Reaction for Eγ up to 150 MeV

Abstract

The reaction ¹⁴N(g,np)3a induced by bremsstrahlung photons of endpoint energy E_g^max = 150 MeV has been investigated using diffusion chamber, which is placed into the magnetic field. The distribution functions of the reaction yield, the energy and momentum of the final particles from Е_g were measured and it was determined that at Е_g > 45 MeV, change in the behavior of these functions occurs. The average energy T^aver was calculated for the particles with the energy falling within a 1 MeV interval of the total kinetic energy T₀ = E_g ‑ Q, where Q is the energy threshold of the reaction (Q = 19.77 MeV). At T₀ ~ 20 MeV, the dependence of the contributions from T^aver to T₀ changes sharply. At T₀ > 20 MeV, most of the energy is carried away by nucleons, their relative contribution is equal, and this agrees with the assumption of the quasideuteron interaction mechanism. The momentum distribution distributions for the neutron and proton have a similar form, with a strong shift of the maximum towards higher energies with an increase in the energy of the γ quantum. For a system of 3α‑particles, in each distribution, peak is observed centered at 100 MeV/c, the relative contribution of which smoothly decreases with increasing momentum, and a wide high-energy "tail" appears. The energy and angular correlations of the np‑pair depends on both of the energy Е_g and the momentum of the system of 3α‑particles.