Neutron-induced fission cross section of 242Pu from 15 MeV to 20 MeV

N Jovančević,F.-J Hambsch,P Salvador-Castineira,C Bonaldi,M Vidali,W Geerts,L Daraban,S Oberstedt,J Heyse

doi:10.1051/epjconf/201714604044

Abstract

Accurate nuclear-data needs in the fast-neutron-energy region have been recently addressed for the development of next generation nuclear power plants (GEN-IV) by the OECD Nuclear Energy Agency (NEA). This sensitivity study has shown that of particular interest is the 242 Pu(n,f) cross section for fast reactor systems. Measurements have been performed with quasi-monoenergetic neutrons in the energy range from 15 MeV to 20 MeV produced by the Van de Graaff accelerator of the JRC-Geel. A twin Frisch-grid ionization chamber has been used in a back-to-back configuration as fission fragment detector. The 242 Pu(n,f) cross section has been normalized to 238 U(n,f) cross section data. The results were compared with existing literature data and show acceptable agreement within 5%.

Highlights

Accurate cross section data for neutron induced nuclear reactions are required for many fields of science, in the energy region up to about 20 MeV
Accurate nuclear-data needs in the fast-neutron-energy region have been recently addressed for the development of generation nuclear power plants (GEN-IV) by the OECD Nuclear Energy Agency (NEA)
Measurements have been performed with quasi-monoenergetic neutrons in the energy range from 15 MeV to 20 MeV produced by the Van de Graaff accelerator of the JRC-Geel

Summary

Introduction

Accurate cross section data for neutron induced nuclear reactions are required for many fields of science, in the energy region up to about 20 MeV. A search of the EXFOR international database of experiments shows that only one set of experimental data exists above 15 MeV and 5 single point measurements between 14 MeV and 15 MeV [2]. Based on this scarcity, in the present work the 242Pu(n,f) cross section was measured at 6 incident neutron energies of 15.28 MeV, 16.16 MeV, 17.22 MeV, 18.02 MeV, 18.74 MeV and 19.81 MeV. That means that the cross section of one sample can be determined relatively to the other sample. A constant fraction discriminator was employed for setting of the electronic threshold for rejecting the signal from α particles

Digital-signal processing

Pulse height analysis

Results

Conclusion