| 摘要 |
PURPOSE:To prevent intermixing of noises by angularly displacing a magnetic field measuring means to a portal supporter so as to swing about the horizontal axis at the measuring position and tilt. CONSTITUTION:A magnetic field measuring means 5 is constituted such that a base table I47 is secured to the floor 156 of a magnetic shielding chamber. 156, and that on the base table 147 a pair of struts 7, 8 are formed to stand with the upper parts of the struts 7, 8 fixed to a ceiling plate 146. The pair of struts 7, 8 and the ceiling plate 146 constitute a portal supporter 43. A support ring 60 is secured to the magnetic field measuring means 5, and to the support ring 60 are secured a pair of fulcrum shafts 14, 15 having the axes on a horizontal straight line. The fulcrum shafts 14, 15 are supported at the measuring position and, being displaced angularly about the horizontal axis, performs swinging and tilting actions. The struts 7, 8 are not provided with any mechanism to elevate the magnetic field measuring means 5, the rigidity of the struts 7, 8 is enhanced so that the natural frequency of the magnetic field measuring means 5 are made 30Hz or more, thereby making the amplitude small and preventing noises from intermixing. |
