Characteristically, early cyclotrons used a weak focusing mechanism

Characteristically, early cyclotrons used a weak focusing mechanism and operated in a field index typically defined by n<1. The stream of the resulting beam occupied a large area. On the other hand, modern cyclotrons have a focusing mechanism that relies on lenses that exploit the technique of transverse focusing systems. However, it is of critical importance for the magnets to be precisely positioned, thus reducing the size of the occupied space (Su, Wagner & Grobe, 5).