Study Of Laser-Polarized ～(129)Xe Via Nuclear Magnetic Resonance

Laser-polarized (hyperpolarized) ¹²⁹Xe, whose nuclear spin polarization can be increased by four or five orders of magnitude over the equilibrium Boltzmann polarization, has been widely used in many fields of natural sciences, especially in nuclear magnetic resonance (NMR). Therefore, the'study of laser-polarized ¹²⁹Xe via NMR'is chosen as the subject of this dissertation, which involves the production and storage of laser-polarized ¹²⁹Xe, radiation damping of laser-polarized ¹²⁹Xe in NMR, spin polarized-induced nuclear Overhauser effect (SPINOE) via laser-polarized ¹²⁹Xe, and the techniques of NMR spectrometer and probe. Significant results are shown as follows:An experimental setup for production of laser-polarized ¹²⁹Xe via spin-exchange optical pumping (SEOP) at low magnetic field in a flow system has been constructed. Based on this setup, in absence of nitrogen gas, production of the laser-polarized ¹²⁹Xe via spin-exchange with optically pumped Cs atoms at the D2 line was firstly reported. The nuclear polarizations of laser-polarized ¹²⁹Xe have been enhanced by factors over 10000, 5000 and 6000 for the gaseous, liquid and solid state, respectively, comparing with those at thermal equilibrium. The storage time of solid laser-polarized ¹²⁹Xe has exceeded three hours at 77 K and 2800 Gauss.The NMR radiation damping effects of the gaseous and liquid laser-polarized ¹²⁹Xe have been firstly observed at low magnetic field in a flow system, and the dynamics of radiation damping has been experimentally studied with different pulse flip angles. The radiation damping time constant of the liquid laser-polarized ¹²⁹Xe was derived on the basis of the theoretical simulation. The envelopes of the ¹²⁹Xe free induction decay (FID) and the spectral lineshape have been theoretically simulated, in the presence of both the transverse relaxation and the radiation damping with different pulse flip angles.For the first time, the solid NMR signal enhancement of 6 for the proton (¹HCl) has been achieved via SPINOE with laser-polarized ¹²⁹Xe. The formula for the SPINOE enhancement in solid state has been theoretically deduced on the basis of the spin-spin dipole-dipole interaction, and the theoretical calculated enhancement of about 7.1 is in agreement with the experimental one. The enhanced ¹³C NMR signal with the...