| 摘要 |
PURPOSE:To enable an adjustment of a center of magnetic field with ease, by providing a yoke plate at each side of a magnet unit and disposing a ring around said yoke plates. CONSTITUTION:Cylindrical ferrite magnets 1 and 1' stand face to face via a ferromagnetic spacer 2, and a magnetic shunt steel 3 is fixed around said ferrite magnets 1 and 1' to restrain alternation of the center field intensity due to temperature variation. A yoke plate 5 is fixed on each side of a magnet unit 4 and a ring 6 is provided around the outer peripheries of the yoke plates 5. The field intensity at a center P of the yoke can be adjusted by rotating the ring 6 and adjusting the distance W between the front end of the ring 6 and the front yoke plate 5. |
