Quantum Theory of Low-Energy Neutron Double-Slit Diffraction

The phenomena of electron, neutron, atomic and molecular diffraction were researched by many experiments in recent year and these experiments were explained by various theory. In this paper, we study the double-slit diffraction of neutron with an approach of quantum mechanics at frist. We find some new results: When slit width a and slit distance d is the ratio of (a+d)/a=n(n=1,2,3,…), order n, 2n, 3n,… are missing in diffraction pattern; When the ratio of (a+d)/a≠n(n=1,2,3,…), there isn’t missing order in diffraction pattern; The length of slit b only affects the diffraction intensity while the thickness c not only affects the intensity, but also changes the missing order in diffraction patterns.