Ang Joyce W L, Bongrand Arthur, Duval Samuel, Donnard Jérôme, Jolis Ester M, Utsunomiya Satoshi, Minomo Kenta, Koivula Risto, Siitari-Kauppi Marja, Law Gareth T W
Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
Singapore Nuclear Safety and Research Initiative, National University of Singapore, Singapore, 138602, Singapore.
Sci Rep. 2024 Mar 5;14(1):5413. doi: 10.1038/s41598-024-52876-w.
Radioactive particles often contain very high radioactivity concentrations and are widespread. They pose a potential risk to human health and the environment. Their detection, quantification, and characterization are crucial if we are to understand their impact. Here, we present the use of a real-time autoradiography gaseous detector (using parallel ionization multiplier) to expedite and improve the accuracy of radioactive particle screening in complex environmental samples. First, standard particles were used to assess the detector capabilities (spatial resolution, spectrometry, and artefact contributions), then, we applied the technique to more complex and environmentally relevant samples. The real-time autoradiography technique provides data with a spatial resolution (≲100 µm) suitable for particle analysis in complex samples. Further, it can differentiate between particles predominantly emitting alpha and beta radiation. Here, the technique is applied to radioactive cesium-rich microparticles collected from the Fukushima Daiichi nuclear exclusion zone, showing their accurate detection, and demonstrating the viability of real-time autoradiography in environmental scenarios. Indeed, for more complex samples (radioactive particles in a less radioactive heterogeneous background mix of minerals), the technique permits relatively high selectivity for radioactive particle screening (up to 61.2% success rate) with low false positive percentages (~ 1%).
放射性粒子通常含有非常高的放射性浓度且分布广泛。它们对人类健康和环境构成潜在风险。如果我们要了解它们的影响，对其进行检测、定量和表征至关重要。在此，我们展示了使用实时放射自显影气体探测器（使用平行电离倍增器）来加快并提高复杂环境样品中放射性粒子筛选的准确性。首先，使用标准粒子评估探测器性能（空间分辨率、光谱分析和伪像贡献），然后，我们将该技术应用于更复杂且与环境相关的样品。实时放射自显影技术提供的空间分辨率（≲100 µm）数据适用于复杂样品中的粒子分析。此外，它可以区分主要发射α和β辐射的粒子。在此，该技术应用于从福岛第一核电站核禁区收集的富含放射性铯的微粒，展示了其准确检测能力，并证明了实时放射自显影在环境场景中的可行性。确实，对于更复杂的样品（在放射性较低的矿物异质背景混合物中的放射性粒子），该技术允许在放射性粒子筛选中具有相对较高的选择性（成功率高达61.2%），假阳性率较低（约1%）。
