Gas adsorption techniques permit pore radius measurements from approximately four Angstroms to five hundred Angstroms employing both classical mesopore and newer micropore methods. See Gas Sorption - Principles of Operation for further information.
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Mercury porosimetry provides measurements of pore radii from several million down to eighteen Angstroms. See Mercury Porosimeter - Principle of Operation for further information.
Electroacoustic provides mean pore size value very rapidly without mercury, cryogens or vacuum pumps. See Principles of Operation.
Capillary flow porometry measures the pore size distribution of through-pores, typically of filters and membranes. See Capillary Flow Porometry - Principle of Operation.