Misure NMR a impulsi su glicerina e caratterizzazione di magnete permanente in NdFeB per applicazioni NMR compatte

Nuclear Magnetic Resonance (NMR) is one of the most powerful and widely used techniques for investigating the structural and dynamical properties of matter, with applications ranging from fundamental physics to chemistry, materials science, and biomedical research. In this thesis, a pulsed NMR setup based on an electromagnet was characterized and used to perform measurements on glycerin, a well-established reference sample for relaxation time studies. The experimental activity included the optimization of the radiofrequency excitation and detection chain, the implementation of pulse sequences, and the measurement of NMR signals to determine the characteristic relaxation parameters of the sample. In addition, the thesis investigated the feasibility of replacing the electromagnet with a compact NdFeB permanent-magnet system. This study focused on the design and characterization of the magnetic field generated by permanent magnets, in order to assess whether a magnetic field homogeneity at the level of 10−4 over the sample volume can be achieved, as required for pulsed NMR measurements. The results demonstrated the need for shim coils in order to develop a compact, energy-efficient NMR instrument based on permanent magnets.