European Commission, Joint Research Centre, Directorate for Nuclear Safety and Security, Nuclear Security Unit, Via Enrico Fermi 2749, 21027, Ispra, VA, Italy.
European Commission, Joint Research Centre, Directorate for Nuclear Safety and Security, Nuclear Security Unit, Via Enrico Fermi 2749, 21027, Ispra, VA, Italy.
Appl Radiat Isot. 2021 Jul;173:109694. doi: 10.1016/j.apradiso.2021.109694. Epub 2021 Apr 2.
We present experimental and MCNP modeled results of neutron flux monitoring in an irradiator, which consists of aCf sealed source housed in the center of a cubic block of high-density polyethylene. This work is contributing to our development in the delayed gamma-ray spectroscopy non-destructive assay technique for nuclear safeguards and security applications. We evaluated the thermal and resonance flux values using the Westcott foil activation method for two measurement position count rates of Au and In. Comparisons between the calculated thermal fluxes from measurements and those from MCNP models show deviations of ~20%. However, both the measured and modeled thermal fluxes are two orders of magnitude higher than the fluxes at the resonance peak energies at both measurement positions, demonstrating that the irradiator is sufficient. Furthermore, this work showed that with aCf sealed source of a strength of 4.4 × 10 n.s, a thermal flux in the range 2-5 × 10 n.s.cm is achievable in our compact irradiator making it suitable for active analysis techniques such as DGS.
我们展示了一个辐照器中中子通量监测的实验和 MCNP 模拟结果，该辐照器由一个位于高密度聚乙烯立方块中心的 Cf 密封源组成。这项工作有助于我们在延迟伽马射线光谱无损 assay 技术方面的发展，用于核保障和安全应用。我们使用 Westcott 箔活化法评估了两个测量位置 Au 和 In 的计数率的热通量和共振通量值。测量得到的热通量与 MCNP 模型计算得到的热通量之间的比较显示偏差约为 20%。然而，无论是测量得到的还是模拟得到的热通量都比两个测量位置的共振峰能量的通量高两个数量级，这表明辐照器是充足的。此外，这项工作表明，使用 4.4×10 n.s 的 Cf 密封源，在我们的紧凑型辐照器中可以实现 2-5×10 n.s.cm 的热通量范围，这使得它适合于主动分析技术，如 DGS。
