A new application of the spark counter: Pore size measurement of nuclear track microfilters

Abstract

Based on the known spark counting technique a method for pore size measurement in nuclear track microfilters is presented. The increased electric strength of a fine pore in a dielectric material is utilized to establish this new method, in which the sparks are counted as a function of the growing sparking voltage. Both electrodes are made from aluminized polyester foil in order to reduce the effect of multiple sparking in the applied voltage range of 600–1800 V corresponding to a pore diameter range of 1.5-0.1 μm. Due to the high pore density of NTMFs it is necessary to add a reduction foil of a low hole density to select some small areas in the NTMF for sparking. In this way the method can be applied to pore size measurement in the porosity range used in separation processes.