Development of The Technology of Biomagnetic Measurement Using High-Temperature Superconductor

高温超导体生物磁测量技术的进展

基本信息

批准号：
11359001
负责人：
KURIKI Shinya
金额：
$ 19.27万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11359001/
关键词：
High-temperature superconductor SQUID Biomagnetism Magnetocardiogram Magnetic shielding

项目摘要

Under the aim to develop the technology of biomagnetic measurement using high-Tc superconductor, we made the following studies and obtained the results described.1. Directly coupled magnetometers were fabricated from YBCO films to have a field noise of less than 100 fT/Hz^<1/2>. The magnetometers have fine structures of slots and holes in μm size on the whole superconducting film and flux dams in the lead film that connects the pickup coil to the SQUID, so that entry and trapping of magnetic flux in the superconducting film would be suppressed. As a result, the magnetometers did not exhibit appreciable increase of low-frequency flux-noise when they were cooled in magnetic fields lower than 30 μT or environmental magnetic field was changed to 1-2 μT.2. In order to reduce environmental magnetic field noises, we investigated various techniques of active compensation that is combined with a soft-shielding simple MSR composed 1-2 layers of μ-metal. A novel compensation method was implemented in which a noise-field detection coil was wound around the MSR wall and a Helmholz-type compensation coil was also wound around the MSR. As a method than is useful in multichannel system, a feedback flux in a flux-locked-loop operation of a magnetometer that detects exclusively field noises was supplied to the feedback coil of other signal-sensing magnetometers. Using such compensation techniques with the soft-shielding MSR, 50-60 dB attenuation of the field noise was possible.3. A multichannel magnetometer system for the measurement of magnetocardiographic signal (MCG) was constructed. The system was installed within the above MSR implemented with the active noise compensation. Real-time MCG signals were measured from the human heart of normal subjects in a wide band-width of 1-100 Hz.

为了开发利用高温超导体进行生物磁测量的技术，我们进行了以下研究并获得了如下结果： 1．采用YBCO薄膜制备了场噪声小于100 fT/Hz^的直接耦合磁力计。 <1/2> 磁力计在整个超导薄膜上具有微米大小的槽和孔的精细结构，并且在连接拾波线圈和传感器的引线薄膜中具有磁通坝。 SQUID，从而抑制磁通量在超导薄膜中的进入和捕获，因此，当磁力计在低于 30 μT 的磁场或环境磁场中冷却时，低频磁通噪声没有明显增加。磁场改为1-2μT。2为了减少环境磁场噪声，我们研究了与由1-2层组成的软屏蔽简单MSR相结合的各种主动补偿技术。 μ-metal 实现了一种新颖的补偿方法，其中将噪声场检测线圈缠绕在 MSR 壁上，并将亥姆霍兹型补偿线圈缠绕在 MSR 上作为一种在多通道系统中有用的方法。使用软屏蔽 MSR 50-60 的补偿技术，将专门检测场噪声的磁力计磁通锁定环操作中的磁通提供给其他信号传感磁力计的反馈线圈。场噪声的dB衰减是可能的。3.构建了用于测量心磁信号(MCG)的多通道磁力计系统，该系统安装在上述MSR内，并实现了实时MCG信号的测量。正常受试者的心脏在 1-100 Hz 的宽带宽内。