The present invention provides a windowframe magnet having an aligned array of paired bedstead coils in mirror symmetry can bend a high aspect ratio ribbon ion beam through angle of not less than about 45 degrees and not more than about 110 degrees, and can focus it through a resolving slot for mass analysis. The long transverse axis of the beam, which can exceed 50% of the bend radius, is aligned with the generated magnetic field. The array of paired bedstead coils provide tight control of the fringing fields, present intrinsically good field uniformity, and enable a manufacture of much lighter construction than other magnet styles conventionally in use in the ion implantation industry. Within the system of the present invention, the ribbon beam is refocused with low aberration to achieve high resolving power, which is of significant value in the ion implantation industry. System size is further reduced by using a small ion source and a quadrupole lens to collimate the beam after expansion and analysis. There is no fundamental limit to the aspect ratio of the beam that can be analyzed.