pISSN 0374-4914 eISSN 2289-0041

## Research Paper

New Physics: Sae Mulli 2016; 66: 162-168

Published online February 29, 2016 https://doi.org/10.3938/NPSM.66.162

## Design and Characterization of a Thermal Neutron Source Based on a 13 MeV Proton Cyclotron

Jeongho KIM1, Seung Wook LEE*1, Suhyun LEE2, Jongyul KIM2, Myung-Kook MOON†2

1 School of Mechanical Engineering, Pusan National University, Pusan 46241, Korea
2 Neutron Instrumentation Division, Korea Atomic Energy Research Institute, Daejeon 34057, Korea

Correspondence to:* seunglee@pusan.ac.kr
moonmk@kaeri.re.kr

Received: November 6, 2015; Revised: December 10, 2015; Accepted: December 18, 2015

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

### Abstract

We have designed and characterized a cyclotron-driven neutron source based on the 13 MeV proton beam for thermal-neutron imaging systems. Accelerator-based neutron sources mainly comprise \romannumeral 1) a target emitting neutrons via nuclear reactions with high energy protons, \romannumeral 2) moderators reducing the kinetic energy of the fast neutrons to allow neutron radiography and \romannumeral 3) reflectors optimizing the divergence of the neutron beam. In this study, a conceptual design consisting of a 1.25 mm-thick beryllium target, a 3 cm-thick HDPE (high-density polyethylene) moderator and a 50 cm-cube-shaped graphite reflector has been proposed. For realistic demonstrations, not only have we calculated the neutron fluences and distributions at up to L/D = 200, where L is the aperture-to-detector distance and D is the aperture diameter, which is an important factor in the field of radiography, but also we have confirmed that the neutron flux of up to $1.4\times10^{5}$ n/cm$^{2}\cdot$s can be obtained when the source-to-detector distance is 3 m.

Keywords: Neutron Source, Cyclotron, Monte Carlo Simulation, \textsc{Geant4}, Target, Moderator, Neutron Radiography