Properties of straight and curved neutron guide tubes

The properties of straight and curved neutron guides for neutrons of the energy region 4·10^?7 eV≦E≦2·10^?6 eV (very cold neutrons) are investigated. Experimental data for the angular distribution of neutrons emerging from a straight neutron guide are presented and it is shown that they can be theoretically verified using Steyerl's approximation. In the second part we consider a strongly curved neutron guide. The effect of laminating such a guide is investigated experimentally and theoretically and the conditions for optimum transmission are discussed.