Development of a small-probe pulsed nuclear magnetic resonance system for measuring magnetic field uniformity
作者:
Shuichi Kato,
Keisuke Maehata,
Kenji Ishibashi,
Yoshihisa Wakuta,
Takakazu Shintomi,
期刊:
Review of Scientific Instruments
(AIP Available online 1997)
卷期:
Volume 68,
issue 3
页码: 1468-1473
ISSN:0034-6748
年代: 1997
DOI:10.1063/1.1147952
出版商: AIP
数据来源: AIP
摘要:
The pulsed nuclear magnetic resonance (NMR) field measurement system is suitable for high-accuracy field homogeneity measurement for accelerator dipole magnets. The measurement has to use NMR probes as small as a few mm in diameter. The coaxial cable connecting the NMR probe and preamplifier has a length of 10 m or more. The coaxial cable has to be treated as a distributed-constant circuit for high-field measurement. We studied the optimum condition of the radio-frequency signal propagation in the coaxial cable, and found that a cable length ofn&lgr;NMR/2(n=1,2,&ellip;) gives optimum propagation characteristics. In accordance with this result, we designed and fabricated a prototype field measurement system using pulsed NMR. The use of a phase-locked loop circuit facilitated the measurement of the frequency of the free-induction-decay signal. To confirm the performance of this system, the magnetic field in the 2 T region of the superconducting solenoid magnet was measured with the NMR probe of which the shape was a cylinder of 4 mm in diameter. ©1997 American Institute of Physics.
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