FEATURES OF ADVANCED NEUTRON OPTICAL DEVICES.

The features of neutron interferometry and neutron magnetic resonance systems are described. The existence of widely separated coherent beams in perfect crystal neutron interferometry permits a great variety of experiments with matter waves in the field of basic quantum mechanics. For example, the phase of the spatial and spinor wave functions can be measured. Recent results on the 4 pi -symmetry of a spinor and the first direct verification of the spin-superposition law are discussed. Multiple Laue reflections are used to achieve an angular resolution up to 0. 001 sec of arc, which permits the observation of wide slit diffraction effects. Neutron magnetic resonance systems allow a uniform energy shift of the neutrons and may be an important component in the future for the realization of systems for dynamical neutron polarization, monochromatization and focusing of neutrons into certain energy, space, angle or time intervals. Additional advantages exist for pulsed sources, very slow neutrons and highly monochromatic beams.