| Project/Area Number |
11359001
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
広領域
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| Research Institution | Hokkaido University |
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Principal Investigator |
KURIKI Shinya Hokkaido University, Research Institute for Electronic Science, Professor, 電子科学研究所, 教授 (30002108)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUDA Mizushi Muroran Institute of Technology, School of Engineering, Associate Professor, 工学部, 助教授 (20261381)
TAKEUCHI Fumiya Hokkaido University, Research Institute for Electronic Science, Lecturer, 電子科学研究所, 助手 (30281835)
HIRATA Yosihiro Hokkaido University, Research Institute for Electronic Science, Lecturer, 電子科学研究所, 助手 (30250509)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥30,110,000 (Direct Cost: ¥28,400,000、Indirect Cost: ¥1,710,000)
Fiscal Year 2001: ¥7,410,000 (Direct Cost: ¥5,700,000、Indirect Cost: ¥1,710,000)
Fiscal Year 2000: ¥10,700,000 (Direct Cost: ¥10,700,000)
Fiscal Year 1999: ¥12,000,000 (Direct Cost: ¥12,000,000)
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| Keywords | High-temperature superconductor / SQUID / Biomagnetism / Magnetocardiogram / Magnetic shielding |
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| Research Abstract |
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.
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