Impact of Be7 breakup on the Li7(p,n) neutron spectrum

Abstract

The formation of continuum neutron distribution in $^{7}\mathrm{Li}(p,n)$ has been identified as due to the coupling of the $^{7}\mathrm{Be}$ breakup levels to the final state of the reaction. The continuum neutron spectra produced by the $^{7}\mathrm{Li}(p,n)$ reaction has been estimated by measuring the double differential cross sections for continuum and resonant breakup of $^{7}\mathrm{Be}$, through the $^{7}\mathrm{Li}(p,n)^{7}\mathrm{Be}^{*}$ reaction at 21 MeV of proton energy. The breakup contributions from continuum and $5/{2}^{\ensuremath{-}}$, $7/{2}^{\ensuremath{-}}$ states of $^{7}\mathrm{Be}$ have been identified. The measured double differential cross sections have been reproduced through continuum-discretized coupled channel-coupled reaction channel calculations. The cross sections were projected to neutron spectrum using the Monte Carlo approach and validated using experimentally measured $^{3}\mathrm{He}$ gated neutron spectra. $^{7}\mathrm{Li}(p,n)$ neutron spectrum at 20 MeV incident proton energy measured by McNaughton et al. [Nucl. Instrum. Methods 130, 555 (1975)] has been reproduced by adapting estimated model parameters for the reaction.