Nuclear Relaxation of ³He Gas on Various Solid Surfaces

Abstract

The nuclear spin–lattice relaxation time of 3 He gas in contact with metallic and glass surfaces has been measured. The relaxation time of the gas in the presence of a glass surface is strongly dependent on both the permeability of the glass to helium and the concentration of paramagnetic impurities in the glass. Two relaxation mechanisms may in this case be distinguished, relaxation due to the diffusion of the gas into the glass and relaxation induced during the adsorption of the helium on the glass surface. A phenomenological model to account for these observations is proposed.The mechanism responsible for the relaxation of 3 He on metallic surfaces remains obscure.