Patent ID: 8884256

Claim:
A septum magnet comprising: a yoke that (i) is arc-shaped, (ii) defines a gap portion at an outer circumference side thereof and extending in a circumferential direction thereof, and (iii) is configured to be separated at approximately a center portion thereof in an axial direction; a septum coil provided inside the gap portion but at an outer side thereof in a radial direction and in which an electric current flows in one direction in the circumferential direction; a return coil, in which an electric current flows in an opposite direction to that of the electric current in the septum coil, provided inside the gap portion in such a way as to (i) be at the inner side thereof in the radial direction and (ii) face the septum coil with a predetermined distance; and a vacuum duct provided within the gap portion such that it is inserted between the septum coil and the return coil, wherein the septum coil is configured to be separated into a first portion and a second portion upon separation of the yoke, and in a space between the septum coil and the vacuum duct, an auxiliary coil is provided in first and second portions in which electric currents flow in opposite directions to each other in the circumferential direction, wherein (i) the first portion of the auxiliary coil is positioned on and fixed to the vacuum duct such that it is between the first portion of the septum coil and the vacuum duct and (ii) the second portion of the auxiliary coil is positioned on and fixed to the vacuum duct such that it is between the second portion of the septum coil and the vacuum duct.