Measurements of neutron scattering angular distributions with a new scintillator setup

Elisa Pirovano,Arnd Junghans,Markus Nyman,Arjan Plompen,Roland Beyer,Ralf Nolte,A Plompen,P Siegler,S Kopecky,F.-J Hambsch,W Mondelaers,S Oberstedt,J Heyse,P Schillebeeckx

doi:10.1051/epjconf/201714611008

Elisa Pirovano, Arnd Junghans + Show 12 more

Open Access

https://doi.org/10.1051/epjconf/201714611008

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Abstract

A new experimental setup for the measurement of neutron scattering cross sections and angular distributions is currently being developed at the neutron time-of-flight facility GELINA, at the JRC-Geel. Up to 32 liquid organic scintillators are employed for the detection of neutrons scattered from a sample of the investigated material. The differential cross section is measured at eight different angles, and the angle-integrated cross section is obtained from the differential data by numerical integration. Two experiments for the study of scattering on iron were carried out, one at GELINA and the other at nELBE (HZDR). The first results for the angular distributions of elastic scattering in the neutron energy range from 2 to 6 MeV are here presented and compared with evaluations from the major nuclear data libraries.

Highlights

Neutron scattering is the most important energy loss mechanism and the main moderation process for fast neutrons in nuclear reactors
A new experimental setup for the measurement of neutron scattering cross sections and angular distributions is currently being developed at the GELINA facility
Up to 32 liquid organic scintillators are employed to detected neutrons scattered from the target sample and to measure the differential cross section at eight different angles

Summary

Introduction

Neutron scattering is the most important energy loss mechanism and the main moderation process for fast neutrons in nuclear reactors. Iron is one of the main reactor structural materials: depending on the structure of the vessel, the volume fraction of iron can up to times higher than that of fuel. Being present in such large quantities, it heavily influences the neutron energy spectrum, the flux distribution and the reaction rates. Some discrepancies exist between evaluated and experimental integral crosssections [2] For these reasons, iron-56 was included in the high priority list for nuclear data of the OECD-NEA [3] and it is one of the six nuclides for the pilot project of the CIELO (Collaborative International Evaluated Library Organization) collaboration [4]

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