¹⁰B(n,α)⁷Li and ¹⁰B(n,α₁γ)⁷Li cross section data up to 3 MeV incident neutron energy

¹ European Spallation Source ERIC, Lund, Sweden
² EC-JRC-Directorate G, Unit G.2, Geel, Belgium
³ Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
⁴ Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania, Italy

^a e-mail: Riccardo.Bevilacqua@esss.se
^b e-mail: Franz-Josef.Hambsch@ec.europa.eu

Published online: 13 September 2017

Abstract

The ¹⁰B(n,α) reaction cross-section is a well-established neutron cross-section standard for incident neutron energies up to 1 MeV. However, above this energy limit there are only scarce direct (n,α) measurements available and these few experimental data are showing large inconsistencies with each other. These discrepancies are reflected in the evaluated data libraries: ENDF/B-VII.1, JEFF-3.1.2 and JENDL-4.0 are in excellent agreement up to 100 keV incident neutrons, whereas the ¹⁰B(n,α) data in the different libraries show large differences in the MeV region. To address these inconsistencies, we have measured the cross section of the two branches of the ¹⁰B(n,α) reaction for incident neutron energies up to 3 MeV. We present here the ¹⁰B(n,α) and the ¹⁰B(n,α₁γ) reactions cross section data, their branching ratio and the total ¹⁰B(n,α) reaction cross section. The measurements were conducted with a dedicated Frisch-grid ionization chamber installed at the GELINA pulsed neutron source of the EC-JRC. We compare our results with existing experimental data and evaluations.