Patent ID: 8698499
Filing Date: 2014-04-15
Classification: G01R,H01F

Abstract:
1. An electromagnet device, of a vertical magnetic field type, which is provided with a pair of static magnetic field generation units for generating a static magnetic field to be induced by a circular current circulating around a center axis and which forms a homogeneous magnetic field region in a space where the pair of the static magnetic field generation units face each other, wherein the static magnetic field generation units comprise at least: a first coil where a first circular current circulates around the center axis in a forward direction; a second coil where a second circular current whose radius is smaller than a radius of the first circular current circulates around the center axis in a backward direction; and a coil group where a plurality of circular currents whose radiuses are smaller than the radius of the second circular current circulate around the center axis in the forward direction and the backward direction alternately in adjacent coils, wherein the first coil, the second coil, and the coil group are arranged so that an elevation angle of each of the first coil, the second coil, and the coil group seen from a center of the homogeneous magnetic field region becomes larger in this order, wherein there exists an empty domain where the second coil and the coil group are not included in an angle domain sandwiched between the elevation angles of the second coil and the coil group, and wherein the empty domain is set in a range having the elevation angle between 26.25° and 55°.