Measurement of general etch rate for CR-39 plastic at short distance scale

Submicron changes in the thickness of solid state nuclear track: detectors during chemical etching can be measured by using a laser interferometer. Such a real-time monitoring allows us to determine with good accuracy the general etch rate of the detectors al very short distance scale. Combined with track measurements from an atomic force microscope, it is possible to study the detector response in this previously unexplored regime. We report a set of measurements for CR-39 plastic detectors obtained with this technique. No short-term variation of general etch rates was found within an accuracy of 5 nm h(-1) beyond the shortest measurable distance of similar to 50 nm. (C) 1997 Elsevier Science B.V.