Impact of γ-Irradiation on Separation of Nuclear Spin-Relaxation Mechanisms Under Magnetic Saturation in a NaF Crystal

Abstract

Studies were carried out on the effect of additional continuous magnetic saturation of the NMR line on nuclear spin relaxation in a NaF single crystal before and after γ-irradiation. The times of magnetization recovery after inversion were measured at room temperature using a Bruker Avance 400 pulse spectrometer. The magnetic saturation was obtained by exciting a long additional resonance pulse. Two main contributions to relaxation for quadrupole ²³Na nuclei, due to spin-phonon coupling in a regular crystalline lattice and due to magnetic centers, were separated by suppressing the latter contribution. γ-irradiation was shown to enhance spin relaxation, however, the magnetic saturation does not suppress the contribution of color centers. The times corresponding to ²³Na relaxation due to spin-phonon coupling in a regular lattice, due to magnetic centers and color centers were evaluated. It was shown that the rate of spin–lattice relaxation for dipole ¹⁹F nuclei was not affected by magnetic saturation.