Resumo
Single uncharged pion production in neutron- and proton-induced reactions on complex nuclei, combined with the nuclear Fermi Gas Model, has been used to evaluate the average equivalent radius of a $(Z,A)$ nucleus directly from the experimental nuclear mass-values of $(Z,A)$ and its neighbors $(Z,A - 1)$ and $(Z - 1,A - 1)$ isobars. A simple formula without adjustable parameters has been derived which gives nuclear radius-values that are in good agreement with updated, equivalent rms radius-values derived from experiments for a set of 540 nuclides comprising spherical, quasi-spherical, stable and long-term
half-life nuclides. We shall call by RFNM-approach the present method of nuclear radius determination.