We have developed a novel method of determining median pore size and p
ore size distributions as a function of spatial position inside a poro
us sample. Pore sizes have been measured with one-, two- and three-dim
ensional spatial resolutions, using nuclear magnetic resonance (NMR) c
ryoporometry in conjunction with magnetic resonance imaging techniques
. NMR cryoporometry is a method of measuring pore sizes and pore size
distributions in the range of less than 40 Angstrom to over 2000 Angst
rom pore diameter, by the technique of freezing a liquid in the pores
and measuring the melting temperature by NMR. Since the melting point
is depressed for crystals of small size, the melting point depression
gives a measurement of pore size.