2002 Fiscal Year Final Research Report Summary
Development of a FM-EPR instrument
| Project/Area Number |
12555114
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Measurement engineering
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| Research Institution | Yamagata University |
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Principal Investigator |
ONO Mitsuhiro Department of Electrical Engineering, Professor, 工学部, 教授 (60007010)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Tetsuya Department of Electrical Engineering, Research Associate, 工学部, 助手 (30312755)
HIRATA Hiroshi Department of Electrical Engineering, Associate Professor, 工学部, 助教授 (60250958)
SHIMOYAMA Yuhei Department of Physics, Hokkaido University of Education, Professor, 教育学部, 教授 (50123948)
SUZUKI Hirosuke Keycom Corporation, Manager of Development and Technical Division, 開発, 取締役開発・技術部長
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| Project Period (FY) |
2000 – 2002
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| Keywords | EPR / ESR / FM / AMC / MRI / ATC / Vibration / AFC |
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| Research Abstract |
A frequency modulation (FM) method was developed to measure electron paramagnetic resonance (EPR) absorption. The first-derivative spectrum of 1,1-diphenyl-2-picrylhydrazyl (DPPH) powder was measured with this FM method. Frequency modulation of up to 1.6 MHz (peak-to-peak) was achieved at a microwave carrier frequency of 1.1 GHz. By using a tunable microwave resonator and automatic control systems, we achieved a practical continuous-wave (CW) EPR spectrometer that incorporates the FM method. In the present experiments, the EPR signal intensity was proportional to the magnitude of frequency modulation. The background signal at the modulation frequency (1 kHz) for EPR detection was also proportional to the magnitude of frequency modulation. An automatic matching control (AMC) system reduced the amplitude of noise in microwave detection and improved the baseline stability. Distortion of the spectral lineshape was seen when the spectrometer settings were not appropriate, e.g., with a lack of the open-loop gain in automatic tuning control (ATC). FM is an alternative to field modulation when the side-effect of field modulation is detrimental for EPR detection, such as in high-field (100-300 GHz) CW-EPR and double resonance EPR. The present spectroscopic technique based on the FM scheme is useful for measuring the first derivative with respect to the microwave frequency in investigations of electron-spin-related phenomena.
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