Calibration of new batches and a study of applications of nuclear track detectors under the harsh conditions of nuclear fusion experiments

Abstract

This paper describes calibration studies of PM-355 detectors manufactured at different times in order to compare their sensitivity to the investigated ions. These studies were motivated by the application of solid-state nuclear track detectors (SSNTDs) in fusion experiments to measure energetic ions escaping from high-temperature plasmas. The CR-39 detector and its new versions such as PM-355, PM-500, PM-600 have been examined for several years at our institute. The PM-355 plastic appeared to be the best, especially for the detection of light ions. However, to use these detectors optimally, especially in spectroscopic measurements, each new batch of PM-355 material should be carefully calibrated.In high temperature plasma experiments the detectors operate under harsh conditions of high temperature, heat impact, intense X-ray, neutron and fast electron radiation. In order to evaluate the effect of these conditions on the crater formation process, some of the α particle- and proton-irradiated PM-355 detector samples were heated in an oven and then etched and scanned. Other alpha- and proton-irradiated samples were exposed to γ and electron radiation of doses varying from 100 to 2000kGy. The irradiated samples were then etched in steps and the bulk etching rate vB of the PM-355 material was determined. The craters induced by the projectiles in both heated and γ and electron irradiated samples differ considerably from the craters observed in non irradiated and non heated samples. Finally, based on the collected data an attempt was made to compare the sensitivity function of detectors from different deliveries, as well as those that were subjected to extreme external conditions. To this end we estimated the values of the sensitivity function v=vTvB for the detectors in question using mainly the simple model of two etching rates vT and vB .