Semiempirical Model for Direct Nuclear Breakup Reactions

A semiempirical model describing the direct breakup of light nuclei by low-energy nucleons is proposed. The model is based upon the assumption that a statistical equilibrium is established with respect to the incident particle and ($\nu -1\mathrm{}$) tightly bound subgroup components of the target nucleus inside of an energy-dependent interaction volume. The interaction volume is taken to be an oblate spheroid which is oriented along the direction of the incident particle path, and which has a minor axis equal to the de Broglie wavelength $\lambda$, and a major axis equal to ($R+a\lambda$), where $R$ and $a$ are parameters characteristic to the particular reaction involved. The direct breakup cross section is calculated for the ${\mathrm{Be}}^9(n, 2n){\mathrm{Be}}^8$ and ${\mathrm{C}}^{12}(n, n^{\prime })3\mathrm{}{\mathrm{He}}^4$ reactions.