  We report the first successful operation of a neutron interferometer having a
separate beam recombining crystal. We achieved this result at the neutron
interferometry setup S18 at the ILL in Grenoble by a collaboration between TU
Wien, ILL Grenoble and INRIM Torino. While previous interferometers were
machined out of a single crystal block, we managed to align two crystals on
nanoradian and picometer scales, as required to obtain neutron interference. As
a decisive proof of principle demonstration, it opens the door to a new
generation of neutron interferometers and exciting applications.
