The neutron field of various irradiation positions of the TRIGA Mark II reactor of the Jožef Stefan Institute (JSI) has been thoroughly characterized by neutron activation dosimetry and miniature fission chambers techniques. In order to have a fully validated calculation scheme to analyze and plan experiments, the gamma field also has to be experimentally validated. The 10-year long collaboration between CEA and JSI is a perfect framework to carry out such a study, and measurements of the gamma field started in late 2016. Several measurement techniques were investigated in in-core and ex-core positions. Online measurements were carried out using miniature ionization chambers (ICs) manufactured by the CEA and PTW Farmer. Positional dependence was studied, showing a decrease in the delayed gamma contribution to the total gamma flux with increasing distance from the reactor core center. To characterize the gamma dose in the core, as well as in the periphery, thermoluminescent and optically stimulated luminescent detectors (TLDs and OSLDs, respectively) were tested. These detectors are commonly used at CEA to measure the gamma dose in a given material, in order to study the nuclear heating in various core elements (control rod, baffle, structural material). Different filters were used in order to assess an integrated dose ranging from a few Gy up to several kGy. The comparisons of experimental results against calculations performed with the JSIR2S code package show a very good agreement. The feasibility of such measurements demonstrates the complementarity between measurements with dosimetry and ICs from low to very high gamma-dose environment, such as in material testing reactors.

中文翻译：

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JSI TRIGA 反应堆中的伽马加热和伽马通量测量：结果和前景


约瑟夫斯特凡研究所 (JSI) TRIGA Mark II 反应堆各个辐照位置的中子场已通过中子活化剂量测定和微型裂变室技术进行了彻底表征。为了有一个完全验证的计算方案来分析和计划实验，伽马场也必须经过实验验证。 CEA 和 JSI 之间长达 10 年的合作是开展此类研究的完美框架，伽玛场的测量于 2016 年底开始。在堆芯内和堆芯外位置研究了几种测量技术。使用 CEA 和 PTW Farmer 制造的微型电离室 (IC) 进行在线测量。研究了位置依赖性，结果表明，随着距反应堆堆芯中心距离的增加，延迟伽马对总伽马通量的贡献减少。为了表征核心以及外围的伽马剂量，测试了热释光和光激发光探测器（分别为 TLD 和 OSLD）。这些探测器通常在 CEA 中用于测量给定材料中的伽马剂量，以便研究各种核心元件（控制棒、挡板、结构材料）中的核加热。使用不同的过滤器来评估从几戈瑞到几千戈瑞的综合剂量。实验结果与使用 JSIR2S 代码包执行的计算的比较显示出非常好的一致性。此类测量的可行性证明了从低到极高伽马剂量环境（例如在材料测试反应堆中）的剂量测定和 IC 测量之间的互补性。