  A microscopic optical potential (OP) is derived from NN chiral potentials at
the first-order term within the spectator expansion of the multiple scattering
theory and adopting the impulse approximation. The performances of our OP are
compared with those of a phenomenological OP in the description of elastic
proton scattering data on different isotopic chains. An analogous scheme is
adopted to construct a microscopic OP for elastic antiproton-nucleus
scattering. The results of our OPs are in reasonably good agreement with the
experimental data, for both elastic proton and antiproton-nucleus scattering.
