Measurements of Neutron Scattering from a Copper Sample Using a Quasi-Differential Method in the Region from 2 keV to 20 MeV

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.

Keywords:

• Neutron scattering
• copper
• Zeus benchmark
• angular distribution
• nuclear data

Acknowledgments

This work was created while some of the authors were employed by the U.S. Government or one of its contractors, and with the scope of such employment, the U.S. Government is granted a non-exclusive royalty-free license to publish, republish, or reproduce the work or to allow others to reproduce this work for U.S. Government purposes.

The authors would like to thank the RPI LINAC staff: Peter Brand, Mathew Gray, Larry Krusieski, and Azeddine Kerdoun. The data presented in this publication would not have been possible without their time and effort. This work was partially supported by the Nuclear Criticality Safety Program, funded and managed by the National Nuclear Security Administration for the U.S. Department of Energy.