Impact of ${}^7$Be breakup on ${}^7$Li(p,n) Neutron Spectrum

Abstract

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