New developments and trends in NMR-ON

New developments and new trends in NMR-ON are presented, especially in the context of precise measurements of nuclear magnetic moments and electric quadrupole moments of short-lived nuclei far off stability with on-line nuclear orientation techniques. The main emphasis is put on the following items:

1. Quadrupole-interaction-resolved NMR-ON (QI-NMR-ON): It is shown that hcp-Co is an ideal matrix for precise measurements of electric quadrupole moments of radioactive nuclei in the region Hg, Au, Pt, Ir, Os. Recently, the first on-line experiment was performed successfully at NICOLE/ISOLDE-CERN and the very interesting quadrupole moment of¹⁸⁶Au could be determined precisely.
2. General problems with lattice location and NMR-ON line widths in long decay chains, such as “lattice-site conservation” by implantation of a suitable precursor.
3. β-decay-induced lattice site change. In the context of integral nuclear orientation measurements on nuclei far off stability, where the β-decay energies become large, lattice site changes may occur, which make the interpretation of γ-anisotropies measured by integral and even time-differential techniques difficult or even impossible. A pilot experiment is described, in which such a β-decay-induced lattice site change has been identified by a double-resonance NMR-ON measurement.