Energy calibration of a CR-39 nuclear-track detector irradiated by charged particles

Charged particle diagnosis is an important aspect of laser–plasma experiments conducted at super-intense laser facilities. In recent years, Columbia Resin #39 (CR-39) detectors have been widely employed for detecting charged particles in laser–plasma experiments. This is because the CR-39 polymer does not respond to electromagnetic pulses or X-rays. This study presents a method for calibrating the relationship between particle energy and track diameter in a CR-39 detector (TasTrak ® ) using 3–8 MeV protons, 6–30 MeV carbon ions, and 1–5 MeV alpha particles. The particle tracks were compared under the manufacturer’s recommended etching conditions of 6.25 mol/l NaOH at 98 °C and under the widely adopted experimental conditions of 6.25 mol/l NaOH at 70 °C. The results show that if the NaOH solution concentration is 6.25 mol/l, then the temperature of 70 °C is more suitable for etching proton tracks than 98 °C and employing a temperature of 98 °C to etch alpha-particle and carbon-ion tracks can significantly reduce the etching time. Moreover, this result implies that C 3+ ion or alpha-particle tracks can be distinguished from proton tracks with energy above 3 MeV by controlling the etching time. This calibration method for the CR-39 detector can be applied to the diagnosis of reaction products in laser–plasma experiments.