Comparison of morphological characteristics for alpha tracks in CR-39 using different radon monitors

CR-39 is a solid nuclear track detector that is commonly used for long-term passive radon monitoring. For a specific incident particle, etching condition and type of CR-39, the morphology of the nuclear tracks in CR-39 varies with the energy and angle of incident particles. This study systematically compares the performance of six different passive radon monitors from the perspective of nuclear track morphology using both theoretical calculations and experiments. Based on different shapes of exposure chambers for these monitors, different strategies for dealing with incident α particles can be observed, especially for those emitted from deposited progeny on the inner wall. These characteristics contribute to the strengths and weaknesses of each monitor in terms of efficiency, uncertainty, robustness in measurement, and consistency of track morphology. The results of this study revealed that the optimisation of the radon monitor should be multidirectional and situation-oriented. It was expected to be helpful to improve radon measurement using these monitors.