For neutrons passing through narrow channels it has been predicted by Lévy-Leblond  and Greenberger  that the quantization of the transverse momentum of the neutron beam changes the longitudinal momentum, resulting in a phase shift that should be measurable by means of neutron interferometry. It is a purely quantum mechanical phenomenon which arises from the wave-like nature of quantum particles.
In this thesis I present the preparation and the results of a series of measurements which have been carried out with a stack of narrow channels in a neutron interferometer. Thermal neutrons with wave lengths of 1.9Å and 2.7Å have been used. The experiments have been performed mostly at the Institut Laue Langevin (ILL) in Grenoble, France, but also at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, USA. First results have been published in .
In addition, I present detailed calculations on the experiment. The channel influence on the neutrons is studied by solving the stationary Schrödinger equation. The wave function is calculated in the channel and behind the channel, for incident plane waves and for localized beams. The wave function gives full information on the confinement induced phase, the transmitted amplitude and the diffraction on the channel edges. The effect of the interferometer crystals on the wave function is calculated using the dynamical theory of diffraction. Finally both calculations are put together in order to describe the neutron beam as a stationary wave packet passing the whole system of the interferometer and the channel stack.
The measurements show that there must be additional phase effects superimposed on the confinement phase. The calculations indicate that these additional phase contributions could arise from the diffraction by the channels in combination with the dynamical diffraction in the interferometer crystals.
 Daniel M. Greenberger, A New Non-Local Effect in Quantum Mechanics, Physica B 151 (1988), 374.
 Jean-Marc Lévy-Leblond, A Geometrical Quantum Phase Effect, Physics Letters A 125 (1987), 441.
 Helmut Rauch, Hartmut Lemmel, Matthias Baron, and Rudolf Loidl, Measurement of a Confinement Induced Neutron Phase, nature 417 (2002), 630.