NMR of He-3 in porous glasses

A study of He-3 in porous glasses is performed in which the observed chemical shifts and lineshapes are attributed to the local magnetic field distribution in the pores and to the distribution of pore shapes. The observed relaxation times T-1 and T-2 are explained by the residual oxygen concentration in the pores and by the diffusion of He-3 in the inhomogeneous local field, respectively. The study indicates that in principle sample tubes containing He-3 in the pores as a built-in lock substance could be produced but the production is not straightforward. He-3 proves to be an ideal nucleus for studying the shape of void structures in solids. (C) 1996 Academic Press, Inc.