In the framework of the radioactive waste drum characterization using neutron coincidence counting, the Nuclear Measurement Laboratory of French Alternative Energies and Atomic Energy Commission (CEA) Cadarache is studying plastic scintillators as an alternative to ideal but costly ³He gas proportional counters. Plastic scintillators are at least five times cheaper for the same detection efficiency, and in addition, they detect fast neutrons three orders of magnitude more quickly than ³He detectors. However, they are sensitive to gamma rays with no pulse shape discrimination abilities for large detection volumes, which implies the necessity to identify precisely gamma background sources that may affect the useful signal. This article presents a detailed analysis of the gamma-ray spectrum of a radioactive waste drum containing glove box filters contaminated by plutonium dioxide. Classical gamma emissions following alpha and beta disintegrations are identified, and also those accompanying inelastic scattering (n, $\text{n}^{\prime }$ ) or radiative capture (n, $\gamma$ ) reactions in the whole waste drum, and ( $\alpha $ , n) or ( $\alpha $ , p) reactions in the filtration media, which can lead to neutron-gamma coincidences parasitizing useful coincidences from plutonium spontaneous fissions.

中文翻译：

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高能反应诱导伽马射线对含钚废料桶的高分辨率伽马光谱分析

在使用中子符合计数的放射性废物桶表征框架内，法国替代能源和原子能委员会 (CEA) 的核测量实验室正在研究塑料闪烁体作为理想但昂贵的³ He 气体正比计数器的替代品。对于相同的检测效率，塑料闪烁体至少便宜五倍，此外，它们检测快中子的速度比^{3 个}数量级快三个数量级他探测器。然而，它们对伽马射线很敏感，对于大检测量没有脉冲形状辨别能力，这意味着必须精确识别可能影响有用信号的伽马背景源。本文详细分析了装有被二氧化钚污染的手套箱过滤器的放射性废物桶的伽马射线光谱。确定了 alpha 和 beta 解体后的经典伽马辐射，以及伴随非弹性散射的那些（n， $\text{n}^{\prime }$ ) 或辐射捕获 (n, $\gamma$ ) 整个废物桶中的反应，和 ( $\alpha $ , n) 或 ( $\alpha $ , p) 过滤介质中的反应，这会导致中子-伽马巧合寄生于钚自发裂变的有用巧合。