Study of Li-nat(p,n) reaction at incident proton energies between 8 and 20 MeV with C-nat backing material

Li-nat(p, n) reaction is a versatile system for the generation of quasi mono-energetic neutrons from epithermal to few hundreds of MeV. The mono-energetic epithermal neutrons serve as a promising alternative source for boron-neutron capture therapy applications for cancer treatment, whereas the high energy reference neutron fields are used as calibration source for high energy physics instrumentations. However, the quasi mono-energetic nature gets disturbed at incident proton energies between 5 and 20 MeV, where different de-excitation modes contribute to the neutron emissions. So, the emission neutron studies at this intermediate proton energy range have not been covered extensively. The present work focuses on the estimation of the relative fraction of different emission neutron groups, along with the neutron spectra and angular distributions for incident proton energies between 8 and 20 MeV. The contribution of different emission neutron groups from Li-nat(p, n) system were calculated using the nuclear reaction model code TALYS and with FLUKA simulations. The results were validated with experimental measurements. The ambient dose equivalents were also estimated from the spectra using the ICRP-116 dose conversion coefficients and compared with the estimates obtained from a neutron dose equivalent meter.