Experimental approach to measure thick target neutron yields induced by heavy ions for shielding

Ngoc Duy Trinh ,M Lewitowicz,C Brouillard,V Desmezières,M Fadil,B Rannou,X Ledoux,T Clerc,E Dessay,S Damoy,A Madeline,G F Grinyer ,Marc Dupuis ,J Grinyer ,Nelly Ménard ,M F Michel ,B Jacquot ,F Porée ,V Morel ,Alain Savalle

doi:10.1051/epjconf/201715301018

Abstract

Double differential (angular and energy) neutron distributions were measured using an activation foil technique. Reactions were induced by impinging two low-energy heavy-ion beams accelerated with the GANIL CSS1 cyclotron: (36 S (12 MeV/u) and 208 Pb (6.25 MeV/u)) onto thick nat Cu targets. Results have been compared to Monte-Carlo calculations from two codes (PHITS and FLUKA) for the purpose of benchmarking radiation protection and shielding requirements. This comparison suggests a disagreement between calculations and experiment, particularly for high-energy neutrons.

Highlights

Nowadays, particle accelerators are used in many different fields from fundamental research to applications in medicine and in industry
In order to maintain a good level of knowledge concerning the radiation protection and shielding requirements and to answer to emerging needs in these fields with next-generation particle accelerators, characterization of potential radiation hazards like neutron yields induced by particle beams must be well known [1,2]
We compare the unfolded spectra to the simulated ones obtained from PHITS and FLUKA for neutrons emitted at 0° with respect to the beam axis

Summary

Introduction

Particle accelerators are used in many different fields from fundamental research to applications in medicine and in industry. In order to maintain a good level of knowledge concerning the radiation protection and shielding requirements and to answer to emerging needs in these fields with next-generation particle accelerators, characterization of potential radiation hazards like neutron yields induced by particle beams must be well known [1,2]. Due to the lack of the data concerning neutron yields induced by heavy-ion reactions around 10 MeV/u [1,2], we performed an experimental campaign at GANIL with the purpose of benchmarking the physics models in transport codes around this low energy limit. Indium, nickel, cobalt, iron, aluminum, niobium and bismuth were chosen as activation foils. This choice permits neutron energies from 0.5 MeV to 70 MeV to be measured. After irradiation of the natCu target, the measurement of the resulting activities in the activation foils was used to reconstruct the incident neutron spectra [3,4,5] using an unfolding method

Methods

Results

Conclusion