Growth of fine holes in polyethylenenaphthalate film irradiated by fission fragments

Abstract
Growth of fine holes by chemical etching in polyethylenenaphthalate films exposed to fission fragments were examined by measuring gas flow through the films. The etching rate along tracks, the radial etching rate, and the bulk etching rate were determined at effective hole diameters of 100–1 000 Å and hole densities of approximately 108 cm−2. The effects of ethanol and surfactants on the etching rates were studied from the viewpoint of attaining less‐tapered holes.