Neutronic studies on a pulsed thermal neutron source based on the Be(p,n) reaction by using a compact proton accelerator
- 作者：Hiroyuki Hasemi ; hasemi@eng.hokudai.ac.jp ; Fujio Hiraga ; Yoshiaki Kiyanagi
- 关键词：Thermal neutron source ; Compact proton accelerator ; Be(p ; n) reaction ; MCNPX ; Neutron imaging
- 刊名：Physics Procedia
- 出版年：2012
- 期刊代码：P128_18753892
- 类别：ph
- 出版时间：2012
- 卷：26
- 期：Complete
- 页码：88-96
- 文件大小：355 K
摘要
A neutron source based on a compact proton accelerator can be used for neutron scattering and imaging experiments. To promote the neutron utilization in various fields of sciences and technologies, it is necessary to develop a high-performance compact accelerator based neutron source for efficient neutron beam experiments. For this purpose, we have performed design studies for an optimal moderator system for thermal neutrons aiming at the imaging. Therefore, we have carried out the neutronic studies by using the MCNPX code. The Be(p,n) reaction was assumed (proton energy 11 MeV), which gives a neutron yield of 2.15x1013 n/sec at 1 mA. Firstly, we studied neutronic characteristics of the intensity, the brightness and the pulse width to choose a moderator material for imaging between light water and heavy water. Secondly, we optimized moderator size and reflector thickness. It was indicated that a thermal neutron flux at 10 m from the moderator was 9.43x105 n/cm2/sec (L/D is 70.7) in case of a slab type. Finally, we investigated the effect of a target cooling system, a moderator vessel and a gap between the Be target and the moderator on a neutron flux. In such a practical model, the thermal neutron flux reduced to about 76%of a simple model.