The properties of liquid helium will be studied by neutron- diffraction techniques. The atomic momentum distribution n(p) will be probed by deep inelastic n scattering, for targets of liquid 3He, 3He - 4He mixtures and 4He, in restricted geometries. In a second study, elastic n scattering will be used to probe the helium structure inside porous media. In particular, one will examine the role of the surface randomness in determining the structure of the crystalline and glassy phases of the solid.
