  Materials subjected to neutron irradiation experience damage due to
displacement cascades triggered by nuclear reactions. This paper presents a
practical method to calculate primary atomic recoil events (PKAs), which lead
to cascade damage, based on energy and recoiling species. We developed a custom
code to identify PKAs and extract their properties using MCNPX and SRIM. This
code determines the specifications of recoil atoms from the data provided by
the PTRAC card in MCNPX. Consequently, the energy spectrum of PKAs generated
through various reaction channels, including elastic/inelastic scattering and
transmutations such as (n, {\alpha}), (n, p), and (n, {\gamma}), is calculated.
This PKA spectrum is then input into SRIM, which calculates the total number of
atomic displacements using the binary collision approximation (BCA) and
provides crucial information about the spatial distribution of defects within
the irradiated material. Our results indicate that elastic scattering is the
predominant reaction, producing most PKAs with energies in the range of several
keV. In contrast, inelastic scattering becomes the dominant interaction for
generating high-energy PKAs (~EPKA>1 MeV). Additionally, we observed that the
number of Frenkel pairs versus ion energy curves for light particle ion
implantation (such as H and He) is significantly smaller than for heavier ions.
