样品在核反应堆内照射是40Ar-39Ar定年技术的前提，而辐照孔道内辐照条件参数是影响样品定年精度的主要因素。目前，我国40Ar-39Ar实验室存在反应堆资源匮乏且辐照条件参数缺乏系统性研究等问题，限制了国内40Ar-39Ar定年技术的发展。申请人拟对高通量试验堆HFETR开展40Ar-39Ar定年工作，在对其辐照条件参数进行探索的基础上，利用核物理手段优化辐照孔道内的辐照条件参数。通过筛选强吸收E＞7Mev中子的屏蔽材料，降低副反应40Ca(n, nα)36Ar的干扰；合理设计中子屏和稳定辐照罐旋转装置，将轴向中子通量梯度降至1%/cm以内，基本消除径向中子通量差异。在此基础上，提供一系列的优化后的针对40Ar-39Ar定年样品的辐照条件参数，最终形成一份利用HFETR辐照不同类型40Ar-39Ar定年样品的技术报告，促进国内40Ar-39Ar同位素年代学的发展和应用。

Samples irradiated in the nuclear reactor is essential to the 40Ar-39Ar dating technique. The parameters of the irradiation channel are main influence factors in the 40Ar-39Ar dating precision. Currently, there have been several problems that limit the development of domestic 40Ar-39Ar dating technique, such as the shortage of reactor resources, the lack of systematic research of the irradiation parameters for samples. In this work, the applicants aim to conduct the irradiation of the samples on high flux engineering test reactor(HFETR), and focus on the optimization of the irradiation parameters by means of nuclear physics on the basis of the primary study of the irradiation channel. The interference of the nuclear reaction 40Ca(n, nα)36Ar will be decreased by selecting special materials which could strongly adsorb the neutrons with energy higher than 7Mev. The proper design of the neutron shielding will limit the gradient of the neutron flux in axial direction within 1%/cm, and the vertical differences of the neutron flux will be almost eliminated through the fix device for the irradiated vessel during the rotation. Based on that, a series of optimized irradiation parameters will be provided, and a detailed report which is for the different kinds of 40Ar-39Ar dating samples irradiated in the HFETR will be established, for the promotion of the development and application of the 40Ar-39Ar geochronology in our country.