Sensitivity enhancement of plastic nuclear track detectors through photo-oxidation

Abstract

A new method is presented for the sensitization of plastic track detectors. It has been found effective for cellulosics, polycarbonates, and polyesters. Most of the reported data deals with Lexan. The method consists of irradiating plastics with ultraviolet radiation, UV, in the presence of oxygen. The sensitivity enhancement is found to increase exponentially with decreasing UV wavelength and increasing particle restricted energy loss rate, REL. This technique can be used to provide a continuously variable sensitivity from sample to sample, within a given sample, or from one etch to the next of a given sample. Greater spatial resolution is possible because of the increase in the ratio rT/rB. Better charge resolution is possible because of the stronger dependence of the track etch rate, ^rT, on REL. Long term measurements show that samples stored in the dark in the O₂ atmosphere show a small increase in ^rT with time. In inert atmospheres a negligible increase is observed, and in a vacuum ^rT decreases.