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arXiv 1507.01398physics.chem-ph
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再论NMR中的核自旋噪声

Nuclear spin noise in NMR revisited

Guillaume Ferrand, Gaspard Huber, Michel Luong, Hervé Desvaux

摘要:

本文考虑接收电路的有限输入阻抗和探头与接收电路之间的传输线,导出了核磁共振中核自旋噪声谱的理论形状。使用这个模型,它成为可能,以重现所有观察到的实验特征:作为传输线相位的函数的NMR共振线宽的变化,核自旋噪声信号出现作为一个“凸点”或作为一个“浸”叠加在平均电子噪声水平,即使对于自旋系统和探针在相同的温度下,纯同相洛伦兹自旋噪声信号表现出非零的频率偏移。实验测量的广泛比较验证了模型的预测,并定义了获得纯同相洛伦兹形状的核自旋噪声与消失的频移的条件,换句话说,同时获得自旋噪声和频移调谐最佳的条件。

英文摘要:

The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite, preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a "bump" or as a "dip" superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparison to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the Spin-Noise and Frequency-Shift Tuning Optima.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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