高能质子轰击重靶的轻带电粒子在线实验研究

Accelerator-Driven Systems (ADS) are one of the proposed options for the incineration of long lived nuclides and minor actinides. In the roadmap towards the demonstration of the ADS concept, an important element is the spallation target, which is the interface between the two principal components of an ADS, the high-power accelerator and the subcritical core. The creation and the accumulation of stable and radioactive nuclides in the target material during the irradiation of the target are a very important issue for many reasons: safety concerns related to gas production, licensing, study of accident cases, target handling and disposal after irradiation. Monte Carlo codes are an essential tool for this kind of investigation, and were used extensively during the design phase, as well as during the experimental measurement program. Light charged particle production of high energy proton beam bombed on heavy target elements were measured on line. The charged fragmentation will be calculated with different models incorporated in the MCNPX, FLUKA,GEANT4 package codes. Through the comparison the code calculations of charged fragmentation with the experimental data, the refined physical model of charged fragmentation parameters are proposed to simplify a technical calculation in real targets.

为了嬗变长寿命产物和次锕系核素，加速器驱动次临界系统（ADS）是一个推荐的选项。在ADS概念中，散裂靶是重要的组成部分，它连接着高功率加速器和次临界堆。对散裂靶而言，辐照产生的放射性核素非常重要，关系到散裂靶安全设计，运行，突发事件以及换靶等方面。在散裂靶设计之初，蒙特卡洛模拟程序是基本的工具，可以模拟散裂靶的各种需求。本项目采用在线实验测量高能质子轰击重靶产生的轻带电粒子，获得散裂反应出射带电产物的双微分截面数据，并采用MCNPX，FLUKA，GEANT4等模拟程序模拟相关结果。通过实验数据与模拟数据比较，探索散裂反应机制，提高散裂靶模拟设计的可靠性。

加速器驱动次临界系统是国际公认为的最有前景嬗变核废料中长寿命产物和次锕系核素的处置手段。加速器驱动次临界系统中，散裂靶是耦合加速器与次临界反应堆的核心部件。散裂靶主要功能是与高能质子束发生散裂反应，产生高能广谱散裂中子，驱动次临界反应堆系统稳定运行。高能粒子束流轰击重金属靶，除了放出大量散裂中子，还会生成大量具有放射性的剩余核素，这些剩余产物的特性及产额对于散裂靶安全设计具有重要的意义。我们通过兰州重离子加速器提供的高能碳束轰击重金属靶，采用在线实验测量高能粒子束流轰击重金属靶产生的出射轻带电粒子，通过ΔE-E法鉴别粒子种类，获得了出射轻带电粒子在特定角度的出射能谱。我们采用Geant4模拟程序模拟了相关过程，通过与实验结果进行比对，检验了散裂反应物理模型的精确性。同时我们开展了高能碳束打重金属靶的出射中子产额的测量，通过水浴活化法得到了400MeV/u轰击厚靶的中子产额为18.4±2.1n/C，我们采用Geant4模拟相应的物理过程，通过三种不同模型比对发现INCL模型的结果与实验结果符合较好。上述研究成果通过实验数据和数值模拟结果的对比，探索了高能粒子轰击重金属靶的散裂反应机理和特征，提高散裂靶模拟设计程序的可靠性。为进一步发展散裂反应模拟代码以及ADS散裂靶装置的设计和运行提供了基础的数据支持。