Macro-autoradiographs of alpha emitters in environmental materials observed with solid-state track detector CR-39

Macro-autoradiographs of alpha emitters in environmental materials were obtained with solid-state nuclear track detector CR-39. This method is applicable only to alpha particles, and because their penetration ranges are very short, the obtained images are very clear. Since the method is simple and inexpensive, it can be used even at the high-school level. From the etch pit density obtained by microscopic observation, the radioactivity density of materials can be determined by using some theoretical calculations.