Deep penetration and activation studies using the high energy neutron field

在KENS空间中子源装置上设置了一个高能中子场辐照室，用于研究材料的屏蔽、活化和辐射损伤。在这个房间里，有一个高能中子源，它是由500 MeV质子轰击厚钨靶产生的。一个普通的混凝土屏蔽4米厚的新组装在房间里，与位于2.5米下游的目标中心的光束出口接触。将铋、铝、铟和金箔的活化探测器插入屏蔽层内的8个狭缝中，通过测量活化探测器的□射线，得到了中子反应率的衰减，并利用MARS 14程序进行了蒙特-卡罗模拟，计算结果与测量结果在2倍以内吻合较好。这些实验数据将作为基准数据，以检查传输计算代码和屏蔽参数的深穿透的准确性。

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.