Radiation lenses including channels consisting of capillaries or fibres, polycapillaries or multilayer planar properly coupled, a central channel filled with refracting material for neutrons and an extraction channel. The channels can be bent with a graded curvature and filled with material with an increasing refracting index, such an increasing refracting index depending on the position of the channel respect the central channel. The lenses can be subdivided into sectors in which the channels have a different curvature and are filled with materials with a different refracting index to increase the combined effect of the total reflection and the refraction. The sectors can be configured in a cubic, cone or prism shape.