Miniaturized lightweight magnetic sector for a field-portable mass spectrometer

A magnetic sector for a double focusing non-scanning mass spectrometer, comprising:

• a yoke of high magnetic permeability material for guiding magnetic flux therethrough, said yoke having a yoke upper surface and a yoke lower surface opposing the yoke upper surface;
• an upper magnet comprising magnetic material which has an energy product density of greater than 1.times.10.sup.7 GOe and having an upper magnet upper surface and an upper magnet lower surface, said upper magnet upper surface connected to and magnetically coupled with the yoke upper surface;
• a lower magnet comprising magnetic material which has an energy product density of greater than 1.times.10.sup.7 GOe and having a lower magnet lower surface and a lower magnet upper surface, said lower magnet lower surface attached to and magnetically coupled with the yoke lower surface;
• an upper pole piece having an upper pole piece upper surface and an upper pole piece lower surface, said upper pole piece upper surface connected to said upper magnet lower surface, said upper pole piece upper surface having the same shape and size as the upper magnet lower surface and attached to and aligned therewith;
• a lower pole piece having a lower pole piece lower surface and a lower pole piece upper surface, said lower pole piece lower surface connected to said lower magnet upper surface, said lower pole piece lower surface having the same size and shape as said lower magnet upper surface and attached to and aligned therewith;
• wherein the upper pole piece lower surface and the lower pole piece upper surface both have the same shape, are both flat, in parallel, and aligned with one another;
• and
• wherein the upper pole piece has a different shape than the lower pole piece.