An Improved Passive CR-39-Based Ddirect ²²²Rn/²²⁰Rn Progeny Detector

• Main Authors: Jun Hu, Guosheng Yang, Chutima Kranrod, Kazuki Iwaoka, Masahiro Hosoda, Shinji Tokonami
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: ²²²Rn progeny; ²²⁰Rn progeny; CR-39; equilibrium equivalent concentration; deposition velocity
• Online Access: https://www.mdpi.com/1660-4601/17/22/8569
• ISSN: 1661-7827; 1660-4601

An improved passive CR-39-based direct ²²²Rn/²²⁰Rn progeny detector with 3 detection channels was designed and tested in this study to measure and calculate equilibrium equivalent concentration (EEC) of both ²²²Rn and ²²⁰Rn without the equilibrium factor. A theoretical model was established to calculate the EEC with optimization. Subsequently, an exposure experiment was carried out to test the performance of this detector, and we compared the chamber experiment and the theoretical model by estimating and measuring various parameters. The deposition flux of progeny derived from the prediction agreed well with the value measured in the exposure chamber. The energy-weighted net track density (NTD) measured by this detector is much more reliable to reflect the linear relation between NTD and time-integrated EEC. Since the detector is sensitive to the exposure environmental condition, it is recommended to apply the detector to measure the EEC after its calibration in a typical indoor environment.