Two-Dimensional Coil System Compensating X, Y, Z-Components of Leakage Field from an Aperture of Magnetic Shields and its Application to a Large-Scale Cylindrical Shield

补偿磁屏蔽孔径漏磁场X、Y、Z分量的二维线圈系统及其在大型圆柱形屏蔽中的应用

• 批准号: 04555094
• 负责人: SASADA Ichiro
• 金额: $ 2.82万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04555094/
• 关键词: Magnetic shield; Magnetic shaking; Figure-eight coil; Opening compensation; Cylindrical shield; Amorphous magnetic material; Biomagnetism; Magnetic field measurement

A new method was developed by which magnetic fields coming in through an opening of a magnetic shield can be compensated. The earth's magnetic field and ac magnetic field were targeted as external magnetic fields to be compensated by the method. A large-scale cylindrical shielding case was developed for this study using a Permalloy cylindrical case (outer diameter =68cm, length=180cm) with an opening at an end and Metglas 2705M amorphous ribbons, which were wound helically on the outer surface of the Permalloy case by 16 layrs. Magnetic shaking field was applied to only the amorphous layrs by a toroidal shaking coil of 36-turns. The cylindrical shielding case was laid on the floor with its axis perpendicular to the direction of the earth's magnetic field. The earth's magnetic field was attenuated to below 0.1 mG (10 nT) at the central region of the shield. The distribution of residual magnetic field was nearly flat due to the cylindrical shape. The horizontal component of the earth's field (0.32 G) as well as vertical one (0.35 G) was compensated at the open end of the cylindrical shield using a flat figure-eight coil (74 cm in diameter) controlled by a feedback system corresponding to each component. Effectively shielded area where residual magnetic field was less than 0.15 mG was extended by about 30 cm (approximately by a radius) toward the open end. Compensating current for the horizontal component of the earth's field was 2.3 A-turn. Magnetic field applied axially by a large square coil was also compensated using a ring coil of the same diameter.By incorporating a newly developed compensating technique we successfully constructed a prototype magnetic shield of human size which is light-weight, high-performance and low-cost

提出了一种新的方法，通过这种方法可以补偿通过磁屏蔽开口进入的磁场。该方法将地磁场和交流磁场作为外磁场进行补偿。本文采用端部开口的坡莫合金圆柱形壳体（外径68cm，长180cm）和Metalloy 2705M非晶薄带，在其外表面螺旋缠绕16层，研制了一种大型圆柱形屏蔽壳体。用36匝环形振荡线圈对非晶层施加振荡磁场。圆柱形的屏蔽罩被放置在地面上，其轴线垂直于地球磁场的方向。地球的磁场在屏蔽的中心区域被衰减到0.1 mG（10 nT）以下。圆柱形结构使剩余磁场的分布趋于平坦。地球磁场的水平分量（0.32G）以及垂直分量（0.35G）在圆柱形屏蔽的开口端处使用由对应于每个分量的反馈系统控制的扁平8字形线圈（直径74cm）来补偿。剩余磁场小于0.15mG的有效屏蔽区域向开口端延伸约30cm（约半径）。地球磁场水平分量的补偿电流为2.3安匝。同时，采用等直径环形线圈对大方形线圈轴向磁场进行补偿，成功地制作出了一个重量轻、性能好、成本低的人体尺寸磁屏蔽样机

项目成果

I.Sasada, I.Inoue, K.Harada: "Multipole Shaking field for Magnetic Shaking" IEEE Transactions on Magnetics. Vol.28, No.1. 3 (1992)

I.Sasada、I.Inoue、K.Harada：“磁振动的多极振动场”IEEE 磁学汇刊。

I.Sasada, Y.Ohnaka: "Experimental study on opening compensation for magnetic shield by current superposition" Journal of applied Physics. Vol.75, No.8, (in print). 3 (1994)

I.Sasada，Y.Onaka：“电流叠加磁屏蔽开路补偿的实验研究”应用物理学杂志。

笹田一郎: "大型円筒磁気シェイキング付き磁気シールドの基礎特性" 日本応用磁気学会誌. 18-2(印刷中). 4 (1994)

Ichiro Sasada：“大型圆柱形磁振动的磁屏蔽的基本特性”，日本应用磁学学会杂志 18-2（出版中）。

笹田一郎: "実用規模磁気シェイキング付き磁気シールドの基礎特性" 電気学会マグネティックス研究会資料. MAG-93-62. 31-40 (1993)

Ichiro Sasada：“具有实际规模的磁振动的磁屏蔽的基本特性”日本电气工程师学会磁学研究组的材料 MAG-93-62（1993）。

I.Sasada, Y.Ohnaka: "Fundamental Characteristics of a Large-Scale Cylindrical Magnetic Shield with Magnetic Shaking (in Japanese)" Journal of Magnetic Society of Japan. Vol.18, No.2, (in print). 4 (1994)

I.Sasada、Y.Onaka：“具有磁振动的大型圆柱形磁屏蔽的基本特性（日语）”日本磁学会杂志。