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A microcoil is an tiny electrical conductor such as a wire in the shape of a spiral or helix which could be a solenoid or a planar structure. The term ‘‘microcoil’’ has conventionally been applied in nuclear magnetic resonance (NMR) spectroscopy to radio frequency (RF) coils which are smaller than 1 mm (thus adopting one definition of the prefix "micro" in terms of the dimensions being tens or hundreds of micrometers). The microcoils have also found usefulness in telemetry systems, where planar microcoils are used to supply energy to miniaturized implants. The detection limits of Micro-MRI or MRM can be pushed further by taking advantage of microsystem fabrication techniques. In general, the RF receiver coil should closely conform to the sample to ensure good detection sensitivity. A properly designed NMR probe will maximize both the observe factor, which is the ratio of the sample volume being observed by the RF coil to the total sample volume required for analysis, and the filling factor, the ratio of the sample volume being observed by the RF coil to the coil volume. The miniaturization of NMR probes thus involves two advantages: # Increased sensitivity which without it the analysis of such low concentration compounds would be impossible, and # Increase of filling factor by matching the probe to the sample volume.〔 Still, the extraction of the NMR spectra of samples having smaller and smaller volumes is a real challenge. Either these reductions of volume are dictated by the difficulties of production of sufficiently large samples or by the necessities of miniaturization of the analysing system, in both cases a careful design of the radiofrequency coils, ensuring an optimum reception of the NMR signal, are required.〔Behrooz, Fateh (2006) (''Modeling, Simulation and Optimization of a Microcoil for MRI-Cell Imaging'' ), Master Thesis, University of Freiburg, Germany〕 ==Microcoil types== Three microcoil types which are commonly used in NMR: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Microcoil」の詳細全文を読む スポンサード リンク
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