Nuclear polarization of short-lived Na isotopes maintained in single crystals for ββ-NMR spectroscopy

A compact ββ-ray detecting nuclear magnetic/quadrupole resonance system with a permanent magnet was developed at ISAC/TRIUMF to measure ground-state electromagnetic moments of short-lived nuclei. Polarized Na beams produced using the collinear optical-pumping technique were used to demonstrate the properties of the system. The degree of nuclear polarization and the spin–lattice relaxation times of the 20,21,26,27,28Na isotopes in NaF, TiO2, LiNbO3, MgF2, ZnO, Pt, and Mg single crystals at room temperature are reported. The electric-quadrupole coupling constants of 20,21Na in TiO2, ZnO and Mg, and that of 27Na in ZnO are also reported. The quadrupole moments of 20,21Na were extracted from the electric-quadrupole coupling constants in ZnO, using the known quadrupole moment of 27Na.