Deep penetration and activation studies using the high energy neutron field

在KENS散裂中子源设施设置了高能中子场辐照室，用于材料的屏蔽、活化和辐射损伤研究。在这个房间里，一个高能中子源是由一个厚钨靶被500兆电子伏的质子轰击而产生的。在与目标中心下游2.5 m的梁出口接触的房间内，新组装了一个4m厚度的普通混凝土护盾。在屏蔽内的8个槽中插入了铋、铝、铟和金箔的激活探测器，并通过测量激活探测器发出的□射线获得了中子反应速率的衰减。还使用MARS 14代码进行了蒙特卡罗模拟，计算和测量结果之间的比较表明在2因子内的一致性很好。该实验数据可作为检验深侵彻传输计算代码和屏蔽参数准确性的基准数据。

An irradiation room for a high-energy neutron field was arranged at the KENS spallation neutron source facility for studies of shielding, activation and radiation damage of materials. In this room, a high-energy neutron source produced in the forward direction from a thick tungsten target bombarded by 500-MeV protons is available. An ordinary concrete shield of 4-m-thickness was newly assembled in the room in contact with the beam exit located 2.5-m downstream from the target center. Activation detectors of bismuth, aluminum, indium and gold foils were inserted into 8 slots inside the shield, and attenuations of neutron reaction rates were obtained by measurements of □-rays from the activation detectors.A Monte-Carlo simulation using the MARS 14 code was also performed, and comparisons between the calculations and measurements show good agreements within a factor of 2. This experimental data will be useful as benchmark data to check the accuracies of the transmission calculation codes and shielding parameters for deep penetration.