We have constructed an atom interferometer of the Mach-Zehnder type,
operating with a supersonic beam of lithium. Atom diffraction uses Bragg
diffraction on laser standing waves. With first order diffraction, our
apparatus has given a large signal and a very good fringe contrast (74%), which
we believe to be the highest ever observed with atom interferometers. This
apparatus will be applied to high sensitivity measurementsComment: 6 pages, 3 figures, accepted by Appl. Phys.