Real-Time Detection and Discrimination of Radioactive Gas Mixtures Using Nanoporous Inorganic Scintillators

Abstract The nuclear industry's expansion to encompass carbon-free electricity generation from small modular reactors and nuclear fuel reprocessing necessitates enhanced detection and monitoring of pure beta-emitting radioactive elements like ³H and ⁸⁵Kr ; this endeavour is crucial for nuclear safety authorities tasked with environmental monitoring. However, the short range of electrons emitted by these gases makes detection challenging. Current methods, such as ionisation chambers and liquid scintillation do not offer at the same time good sensitivity, real-time analysis, and ease of implementation. We demonstrate an approach using a gas-solid mixture to overcome these limitations. We synthetized a transparent and scintillating nanoporous material, an aerogel of Y₃Al₅O₁₂:Ce⁴⁺ and achieved real-time detection with an efficiency of 96% for ⁸⁵Kr and 20\% for ⁸⁵H. The method reaches a sensitivity bellow 100 mBq per cm³ over 100 s measurement time. Statistical analysis of the temporal responses allows measurement of gas mixtures containing both ³H and ⁸⁵Kr . We are able to measure simultaneously pure beta emitters, a capability not possible previously. Our results demonstrate a compact and robust detection system for in-line measurement of strategic radioactive gases. This combination of concept and method enhances nuclear powerplant management and contributes to environmental safeguarding. Beyond the detection issues, this concept opens a wide field of new methods for radionuclide metrology.