Magnet arrangements.

摘要

In a magnet arrangement suitable for providing PPM focusing, cylindrical magnets 4 have inclined inner faces 6 and 7 meeting at an edge 8. Pole pieces 9 are contiguous with the inclined faces 6 and 7 to provide a relatively large field within the volume enclosed by the arrangement. Preferably, the magnet is of a type II magnetic material. <IMAGE>