**Figure 4.**

*A vertical ribbon beam 150 mm tall at the ion source expands vertically, is analyzed by a 90<sup>o</sup> magnet with 'bedstead' coils, expands to 1300 mm, and is collimated by a U-multipole [15], which also adjusts the uniformity.*

central axis. In this manner we were able to achieve +/ 2% uniformity in the arc chamber and permit substantially uniform ionization.
