Shielding experiments of concrete and iron for the 244 MeV and 387 MeV quasi-mono energetic neutrons using an organic scintillator (at RCNP, Osaka Univ.)

Masayuki Hagiwara,Tetsuro Matsumoto,Yosuke Iwamoto,Hiroshi Yashima,Kichiji Hatanaka,Takashi Nakamura,Hiroshi Iwase,Atsushi Tamii,Hiroshi Nakashima,Tatsushi Shima,Yoshihiro Nakane,Daiki Satoh,Yukio Sakamoto,Akihiko Masuda,F Malvagi,C.M’B Diop,F Malouch,J.C Trama,J Miss

doi:10.1051/epjconf/201715308021

Abstract

A shielding benchmark experiment has been performed using a quasi-monoenergetic 7 Li(p,n) neutron source with the peak energies of 244 and 387 MeV at the Research Center for Nuclear Physics (RCNP) of Osaka University, in order to assess the accuracy of nuclear data and calculation codes used in high-energy accelerator shielging design. Energy spectra behind bulk shields of 10- to 100-cm-thick iron, 25- to 300-cm-thick concrete and their composite are measured using a NE213 organic liquid scintillator with a diameter and thickness of 25.4 cm each with a time-of-flight and an unfolding method. The neutron attenuation lengths are illustared for iron and concrete as a function of the incident energy.

Highlights

In recent years, accelerators have been used for various purposes of fundamental research fields such as nuclear physics, material and life science and industrial and medical applications
The shielding benchmark experiment using the p-7Li quasi-monoenergetic neutron sources have been performed for 40 and 65 MeV in Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), Japan Atomic Research Agency [1, 2] and for 137 MeV in the Research Center for Nuclear Physics (RCNP), Osaka University, Japan [3, 4], because the data are very useful to investigate the attenuation length of monoenergetic neutrons and the accuracy of nuclear data libraries and nuclear reaction models implemented in the simulation codes used for accelerator shielding designs
In order to extend the shielding benchmark experiment using p-7Li quasi-monoenergetic neutron sources to higher energies, we have developed the irradiation field of p-7Li quasi-monoenergetic neutron sources with the peak energies of hundreds of MeV in RCNP. [3, 5] In 2009, we have performed a seris of benchmark experiments using a NE213 scintillator of 25.4-cm in diameter and 25.4-cm in thickness [6] and a Bonner sphere spectrometer [7] for the hundreds of MeV p-7Li quasi-monoenergetic neutron sources, and obtained the pleliminary neuron spectra in time and energy behind iron and concrete shields with several thicknesses from 10- to 300-cm for the p-7Li quasi-monoenergetic neutron sources with the peak energies of 244 and 387 MeV

Summary

Introduction

Accelerators have been used for various purposes of fundamental research fields such as nuclear physics, material and life science and industrial and medical applications. In order to extend the shielding benchmark experiment using p-7Li quasi-monoenergetic neutron sources to higher energies, we have developed the irradiation field of p-7Li quasi-monoenergetic neutron sources with the peak energies of hundreds of MeV in RCNP. [3, 5] In 2009, we have performed a seris of benchmark experiments using a NE213 scintillator of 25.4-cm in diameter and 25.4-cm in thickness [6] and a Bonner sphere spectrometer [7] for the hundreds of MeV p-7Li quasi-monoenergetic neutron sources, and obtained the pleliminary neuron spectra in time and energy behind iron and concrete shields with several thicknesses from 10- to 300-cm for the p-7Li quasi-monoenergetic neutron sources with the peak energies of 244 and 387 MeV. The neutron attenuation length were obtained for iron and concrete as a function of neutron incident energies

Experimental facility and setup

Measurement of neutron spectra behind Shields

Energy spectra

Attenuation length

CONCLUSION