高能中子辐照场的布置及在日本国立放射医学综合研究所使用4米厚混凝土的屏蔽实验

Arrangement of high-energy neutron irradiation field and shielding experiment using 4 m concrete at KENS.

作者信息

Nakao N, Yashima H, Kawai M, Oishi K, Nakashima H, Masumoto K, Matsumura H, Sasaki S, Numajiri M, Sanami T, Wang Q, Toyoda A, Takahashi K, Iijima K, Eda K, Ban S, Hirayama H, Muto S, Nunomiya T, Yonai S, Rasolonjatovo D R H, Terunuma K, Yamauchi K, Sarkar P K, Kim E, Nakamura T, Maruhashi A

机构信息

High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan.

出版信息

Radiat Prot Dosimetry. 2005;116(1-4 Pt 2):553-7. doi: 10.1093/rpd/nci013.

DOI:10.1093/rpd/nci013

PMID:16604697

Abstract

An irradiation field of high-energy neutrons produced in the forward direction from a thick tungsten target bombarded by 500 MeV protons was arranged at the KENS spallation neutron source facility. In this facility, shielding experiment was performed with an ordinary concrete shield of 4 m thickness assembled in the irradiation room, 2.5 m downstream from the target centre. Activation detectors of bismuth, aluminium, indium and gold were inserted into eight slots inside the shield and attenuations of neutron reaction rates were obtained by measurements of gamma-rays from the activation detectors. A MARS14 Monte Carlo simulation was also performed down to thermal energy, and comparisons between the calculations and measurements show agreements within a factor of 3. This neutron field is useful for studies of shielding, activation and radiation damage of materials for high-energy neutrons, and experimental data are useful to check the accuracies of the transmission and activation calculation codes.

摘要

在KENS散裂中子源设施中，布置了一个由500 MeV质子轰击厚钨靶向前产生的高能中子辐照场。在该设施中，在距靶中心下游2.5 m的辐照室内，用4 m厚的普通混凝土屏蔽层进行了屏蔽实验。将铋、铝、铟和金的活化探测器插入屏蔽层内的八个插槽中，并通过测量活化探测器发出的伽马射线获得中子反应率的衰减。还进行了低至热能的MARS14蒙特卡罗模拟，计算结果与测量结果的比较表明，两者在3倍的范围内相符。该中子场对于研究高能中子材料的屏蔽、活化和辐射损伤很有用，实验数据对于检验传输和活化计算代码的准确性很有用。