  We achieved a tripling of the maximum range of perpendicular momentum
transfer (q_z) of X-ray scattering from liquid surfaces using a double crystal
deflector setup to tilt the incident X-ray beam. This is obtained by using
Miller indices of the reflecting crystal atomic planes that are three times
higher than usual. We calculate the deviation from the exact Bragg angle
condition induced by a misalignment between the X-ray beam axis and the main
rotation axis of the double crystal deflector and deduce a fast and
straightforward procedure to align them. We show measurements of X-ray
reflectivity up to q_z=7A^(-1) on the bare surface of liquid copper and on
graphene on liquid copper.
