Nuclear reactions with oriented nuclei

In this chapter, the use of oriented nuclei as targets in nuclear reactions is discussed. A few aspects of oriented nuclear targets and polarized projectiles are considered in some detail. The use of density matrix elements for nuclear reactions is briefly described, with an extension to impure spin states. Several technical aspects are reviewed. Specialized topics of nuclear reactions, in which oriented targets are used, are discussed. Some of these experiments need both polarized nuclei and polarized projectiles, e.g. the determination of neutron resonance spins. In other cases the combination of aligned nuclei and unpolarized projectiles suffices, e.g. for fission fragment directional distributions and nuclear shape effects. In capture-γ-ray emission measurements with (i) aligned nuclei and (ii) polarized nuclei/polarized neutrons, produce complementary information. (Auth.)