Abstract

Neutron scattering from a copper sample was measured at Rensselaer Polytechnic Institute utilizing the quasi-differential method. The measurement spanned the energy range from 0.5 to 20 MeV using the high-energy scattering system and from 2 keV to 0.5 MeV using the new mid-energy scattering system. Copper was selected as a material of interest to measure due to large discrepancies between experiments and simulations of the Zeus benchmark. The Zeus benchmark consists of a copper reflected highly enriched uranium system, and the angular distribution of copper scattering was thought to potentially be the cause of the discrepancy. The copper measurements found differences in the scattering response particularly in the incident energy region from 1 to 2 MeV for the high-energy measurement and from 2 to 4 keV in the mid-energy system. These differences are particularly noticeable at angles near 90 deg in the high-energy system and back angles in the mid-energy system. Additionally, for ENDF/B-VIII.0 there is a large discrepancy at the forward angle in the energy range around 0.5 MeV. For these reasons, a new evaluation of copper scattering utilizing these results is recommended and perhaps could help to improve the agreement with the Zeus benchmarks.

摘要

伦斯勒理工学院使用准微分法测量了铜样品的中子散射。使用高能散射系统测量的能量范围为 0.5 至 20 MeV，使用新的中能散射系统的测量能量范围为 2 keV 至 0.5 MeV。由于 Zeus 基准的实验和模拟之间的巨大差异，铜被选为感兴趣的测量材料。Zeus 基准由铜反射的高浓缩铀系统组成，铜散射的角分布被认为可能是造成差异的原因。铜测量发现了散射响应的差异，特别是在高能测量的 1 到 2 MeV 和中等能量系统中的 2 到 4 keV 的入射能量区域。这些差异在高能系统中接近 90 度的角度和中能系统中的背角处尤为明显。此外，对于 ENDF/B-VIII.0，在 0.5 MeV 左右的能量范围内，前向角存在很大差异。由于这些原因，建议使用这些结果对铜散射进行新的评估，这可能有助于提高与 Zeus 基准的一致性。