New type of low temperature source of Ultra-cold neutrons and production of continous beams of UCN

We discuss a new type of source for Ultra-cold neutrons (UCN) in which the UCN are produced in a thin film on the walls of a cryogenic container. The UCN build up to a significant density inside the container, and the build-up time can be adjusted without effecting the UCN density. Applications to the production of intense, continous beams of UCN for scattering experiments are emphasized. The new source is well suited for installation inside the moderator of an intense neutron source.