MEND-a code for calculating nuclear data of medium-heavy nuclei below 250 MeV

Based on the spherical optical model, pre-equilibrium statistical theory, and Hauser-Feshbach theory, etc., the code MEND (Medium Energy Nuclear Data) is written for calculating the complete set of nuclear data of medium-heavy nuclei in medium-low energy region (≤ 250 MeV). For the reactions induced by neutron and proton below 250 MeV, the total cross sections, reaction cross sections, elastic scattering differential cross sections, double differential cross sections and energy spectra, etc. calculated by the code MEND, generally agree with those corresponding experimental data. MEND is a foundational program for nuclear reaction in medium-low energy region and is widely used for nuclear data calculation and establishing ENDF/B6 format files of medium-low energy region in China. (authors)