An apparatus for ion implantation using high perveance beams is disclosed. The apparatus includes a dipole magnet apparatus that provides an adjustment to a cross-beam magnetic dipole field in an ion implantation system. Introduction and control of the magnetic dipole field gradient in a low energy implantation system as disclosed herein gives a significant improvement to the magnet's acceptance and beam focusing which largely defines the effective transported beam current. The apparatus involves the use of ferromagnetic yokes of a prescribed shape and a portion of a secondary magnet coil following along the outside radius of a set of primary dipole magnet coils which define and delineate the primary magnetic field area and beam path. The current return path for the secondary magnet coil is via another portion of the secondary magnet coil that follows a path such that the field generated by the return path secondary magnet coil is orthogonal to the primary magnetic field. The resulting magnetic field across the beam cross-section has a sloping shape with relative maxima and minima near the transverse beamline boundary. The action of the magnetic field distribution on the ion beam acts to compensate the space-charge dispersion of high perveance beams.