Development of High Energy Resolution Neutron Spectrometer for Fusion Reactor Material Irradiation Test Faclility

本课题旨在研制一种适用于聚变反应堆材料辐照试验实验中加速器中子源常规监测的新型中子探测器。其探测原理基于斜散射几何中的反冲核反望远镜技术，其独特思想是在入射中子束平行位置放置大面积反冲核发射器（辐射器），并在远离中子束的辐射器和反冲核探测器之间插入反冲核多微准直板。该系统的优点是通过调整探测器元件的几何参数，如辐射体的厚度和面积、反冲核微准直器的形状等，实现了高能量分辨率和高探测效率以及良好的抗辐射性能的兼容。在聚变反应堆材料辐照试验实验中，计算了1 - 50 MeV能量范围内的中子的精确探测器响应。制作了1/24模型对应的探测器样机，并利用加速器14MeV中子源进行了性能测试，结果验证了探测器概念和设计计算的有效性。根据14MeV中子源监测的要求，通过优化的实例设计，建立了探测器规格的确定程序。利用一些微加工技术证明了制造反冲核微准直板的可能性，而反冲核微准直板是实现现有探测器概念所必需的。通过对14MeV以上能谱区的设计考虑，明确了预测的性能和存在的问题。

The present study is aiming at the development of a new type neutron detector suitable for routine monitoring of accelerator neutron sources which are expected for fusion reactor material irradiation test experiments. The detection principle is based on recoil nucleus counter telescope technique in oblique scattering geometry with unique ideas that a large area recoil nucleus emitter (radiator) is placed In parallel to the incident neutron beam and a multi-micro collimation plate for recoil nuclei is inserted between the radiator and recoil nucleus detectors away from the neutron beam. The excellence of this system can reaIize the compatibility of high enegy resolution and high detection efficiency together with good radiation resistance by adjusting the geometrical parameters of the detector elements such as the radiator thickness and area, the shape of recoil nucleus microcollimators, etc.The main research results are summarized as follows ;1.The program to calculate the precise detector response was developed for neutrons in the energy region between 1 and 50 MeV expected for fusion reactor material irradiation test experiments.2.A prototype detector correspnding to 1/24 model was manufactured and the performance test was made by using an accelerator 14MeV neutron source, of which results verified the validity of the present detector concept and design calculation3.The procedure to determine the detector specification was established through an example design optimized to the requirements for 14MeV neutron source monitoring4.The posibility of manufacturing a recoil nucleus microcollimation plate, which is essential to reaIize the present detector concept, was demonstrated by some micromacnining technique.5.The predicted performance and problems were made clear through design consideration for neutron spectrometry in the energy region higher than 14MeV.