Nuclear energy levels in tulium-169 and lutetium-175

The electron-capture decay of Yb169 to Tm169 and the beta-decay of Yb175 to Lu175 have been studied using the curved-crystal gamma-ray diffraction spectrometer, the ring-focusing beta-ray spectrometer, and the semicircular homogeneous-field beta-ray spectrometer. The precision energies and the multipolarities of Tm169 and Lu175 nuclear transitions have been determined, and energies, spins and parities of the nuclear levels are proposed. The principal experimental techniques are reviewed, and the results of preliminary measurements of the curved-crystal spectrometer reflection coefficient are indicated. The observed nuclear levels and transitions in Tm169 and Lu175 are discussed on the basis of the Bohr-Mottelson unified nuclear model