A hydrogen ion implanter for the exfoliation of silicon from silicon wafers uses a large scan wheel carrying 50+ wafers around its periphery and rotating about an axis. In one embodiment, the axis of rotation of the wheel is fixed and a ribbon beam of hydrogen ions is directed down on a peripheral edge of the wheel. The ribbon beam extends over the full radial width of wafers on the wheel. The beam is generated by an ion source providing an extracted ribbon beam having at least 100 mm major cross-sectional diameter. The ion source may use core-less saddle type coils to provide a uniform field confining the plasma in the ion source. The ribbon beam may be passed through a 90° bending magnet which bends the beam in the plane of the ribbon.