Low-temperature nuclear orientation: Possibilities, results, perspectives

The theoretical expressions, which describe the directional distribution of gamma rays emitted by oriented nuclei and the deorientation coefficients, have been analyzed, and the generalization of these expressions was made fo r the case of the level population from any number of the initally oriented nuclear states. The possibilities and also restrictions of the low-tempera ture nuclear orientation method are shown and are illustrated by our experi mental and theoretical results. The most possibilities of ffered by the nuc lear orientation study were used. For example, hundreds of spin values, I, I-i, and I-f, and of the E2/M1, M2/E1, E3/M2 and E0/E2 mixing ratios, the m echanismus of orientation of EuGd and YbGd, the magnitudes of the magnetic dipole moments of the Gd-147 and Gd-149 ground states, the attenuation fact ors of orientation of the excited states in Yb-171, th, E2/M1 mixing ratio sign change when going from Yb-169 to Yb-171 (observation of the space refl ection property), the intensities of the components with different multipol arities in the beta transition from (EuFe)-Eu-154 and so on where determine d. The studied nuclei were interpreted in the frame of the quasiparticle-ph onon model of Soloviev, of this model with a Coriolis interaction, of the I BA models and of the dynamic deformation model. Some future developments an d possibilities are shown.