Optimization of a photoneutron source based on 10 MeV electron beam using Geant4 Monte Carlo code

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• 作者：Boubaker Askri ; ^{askrib@gmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Photonuclear ; Geant4 ; Neutron source ; Monte Carlo ; Electron beam
• 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• 出版年：2015
• 出版时间：1 October 2015
• 年：2015
• 卷：360
• 期：Complete
• 页码：1-8
• 全文大小：1149 K

文摘

Geant4 Monte Carlo code has been used to conceive and optimize a simple and compact neutron source based on a 10 MeV electron beam impinging on a tungsten target adjoined to a beryllium target. For this purpose, a precise photonuclear reaction cross-section model issued from the International Atomic Energy Agency (IAEA) database was linked to Geant4 to accurately simulate the interaction of low energy bremsstrahlung photons with beryllium material. A benchmark test showed that a good agreement was achieved when comparing the emitted neutron flux spectra predicted by Geant4 and Fluka codes for a beryllium cylinder bombarded with a 5 MeV photon beam. The source optimization was achieved through a two stage Monte Carlo simulation. In the first stage, the distributions of the seven phase space coordinates of the bremsstrahlung photons at the boundaries of the tungsten target were determined. In the second stage events corresponding to photons emitted according to these distributions were tracked. A neutron yield of 4.8 × 10¹⁰ neutrons/mA/s was obtained at 20 cm from the beryllium target. A thermal neutron yield of 1.5 × 10⁹ neutrons/mA/s was obtained after introducing a spherical shell of polyethylene as a neutron moderator.