SHAKING OPEN TYPE MAGNETIC SHIELD STRUCTURE

PROBLEM TO BE SOLVED: To provide a shaking open type magnetic shield structure capable of keeping leakage of shaking noise small.SOLUTION: Annular belt-like magnetic plates 10 are provided, respectively, on multiple stages of parallel planes Pz1, Pz2, ... crossing a first direction axis Az penetrating a magnetic shield object space 1 at predetermined intervals dz, so as to surround the object space 1 with a predetermined belt width W. A conductor coil 20 is wound around each stage of the annular belt-like magnetic plates 10, at a predetermined pitch T, along the annular axis. Annular conductors 50 of substantially same diameter as the annular belt-like magnetic plates 10 are provided, respectively, in parallel in the gap dz of open type magnetic shield structure 5z of each stage. The annular belt-like magnetic plates 10 are subjected to magnetic shaking by applying a shaking current of a predetermined frequency from a coil driver 30 to conductor coil 20, and leakage magnetic field on the outside of the conductor coil 20 is cancelled by applying a cancellation current from a conductor driver 60 to the annular conductors 50.SELECTED DRAWING: Figure 1 【課題】シェイキングノイズの漏洩を小さく抑えることができるシェイキング式の開放型磁気シールド構造を提供する。【解決手段】磁気シールド対象空間１を貫く第１方向軸Ａｚと所定間隔ｄｚで交差する複数段の平行な平面Ｐｚ１，Ｐｚ２，...上にそれぞれ対象空間１を所定帯幅Ｗで囲むように環帯状磁性板１０を設け，環帯状磁性板１０の各段にそれぞれ環状軸に沿って所定ピッチＴで導線コイル２０を巻き付け，各段の開放型磁気シールド構造５ｚの間隔ｄｚにそれぞれ環帯状磁性板１０と実質上同径の環状導体５０を平行に設け，コイル駆動装置３０から導線コイル２０に所定周波数のシェイキング電流を印加して環帯状磁性板１０を磁気シェイキングすると共に，導体駆動装置６０から環状導体５０にキャンセル電流を印加して導線コイル２０外側の漏洩磁場を打ち消す。【選択図】 図１