Impact of Be-7 breakup on the Li-7(p, n) neutron spectrum

The formation of continuum neutron distribution in Li-7(p , n) has been identified as due to the coupling of the Be-7 breakup levels to the final state of the reaction. The continuum neutron spectra produced by the Li-7(p , n) reaction has been estimated by measuring the double differential cross sections for continuum and resonant breakup of Be-7, through the Li-7(p , n) Be-7* reaction at 21 MeV of proton energy. The breakup contributions from continuum and 5/2- , 7/2- states of Be-7 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 He-3 gated neutron spectra. Li-7(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.