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

Abstract

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.

Keywords:

• macro-autoradiograph
• alpha emitter
• nuclear track detector
• CR-39
• environmental material
• radioactivity

Acknowledgements

This research was initiated as a joint effort between the Super Science High School project promoted by Mr Makoto Mishima of Okayama prefectural Ichinomiya High School and Mr Jun Kawai of the Mitsubishi Research Institute. Prof. Nobuhito Ishigure of Nagoya University provided the author with valuable comments on this study. Dr Takahiro Yamada of Japan Radioisotope Association determined the radioactivity of a RaDEF alpha-particle standard source and provided the author with an opportunity to use it. Prof. Takao Iida and Assoc. Prof. Jun Moriizumi of Nagoya University gave valuable advice on chemical etching of CR-39. The author would like to express his sincere thanks to each of them.