Abstract : 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.
https://hal-cea.archives-ouvertes.fr/cea-01171610
Contributeur : Herve Desvaux <>
Soumis le : vendredi 21 août 2015 - 17:16:28
Dernière modification le : samedi 18 février 2017 - 01:16:04
Document(s) archivé(s) le : mercredi 26 avril 2017 - 10:06:51
