Matsumura Hiroshi, Masumoto Kazuyoshi, Nakao Noriaki, Wang Qingbin, Toyoda Akihiro, Kawai Masayoshi, Aze Takahiro, Fujimura Masatsugu
High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan.
Radiat Prot Dosimetry. 2005;116(1-4 Pt 2):1-5. doi: 10.1093/rpd/nci012.
We carried out a shielding experiment of high-energy neutrons, generated from a tungsten target bombarded with primary 500-MeV protons at KENS, which penetrated through a concrete shield in the zero-degree direction. We propose a new method to evaluate the spectra of high-energy neutrons ranging from 8 to 500 MeV. Au foils were set in a concrete shield, and the reaction rates for 13 radionuclides produced by the spallation reactions on the Au targets were measured by radiochemical techniques. The experimental results were compared with those obtained by the MARS14 Monte-Carlo code. A good agreement (between them) was found for energies beyond 100 MeV. The profile of the neutron spectrum, ranging from 8 to 500 MeV, does not depend on the thickness of the concrete shield.
我们在日本高能加速器研究机构（KENS）进行了一项高能中子屏蔽实验，该高能中子由被初级500兆电子伏特质子轰击的钨靶产生，且沿零度方向穿透混凝土屏蔽层。我们提出了一种新方法来评估能量范围在8至500兆电子伏特的高能中子能谱。将金箔置于混凝土屏蔽层中，并用放射化学技术测量金靶上散裂反应产生的13种放射性核素的反应速率。将实验结果与通过MARS14蒙特卡罗代码获得的结果进行比较。发现在能量超过100兆电子伏特时（两者之间）吻合良好。能量范围在8至500兆电子伏特的中子能谱分布不依赖于混凝土屏蔽层的厚度。
