摘要:
在低温核天体物理环境下,如静态核稳定燃烧阶段的核反应都发生较低的能区,其伽莫夫窗口内的核反应截面非常小,这就需要加速器提供较强束流才能完成核反应截面的直接测量.最近在中国科学院近代物理的320 kV高压平台上建立了低能核天体物理实验室以及相应的研究平台.驱动该平台的是一个14.5 GHz的永磁铁型ECR离子源,它能够提供非常强的束流离子.对于质子和氦离子,离子源出口的最大流强可以达到100 eμA,在实验终端上可以获得大约30 eμA的流强.基于此强流加速器装置,我们建立了核天体物理实验测量装置,包括靶室以及带电粒子和伽玛射线探测器等设备.利用已知的核反应对探测器性能和实验方法进行了一系列测试.同时,展示了近年来取得的一些主要实验结果.最后,对该平台上开展工作的前景进行了展望,并指出基于该地面装置的低能核反应研究所积累的技术及经验对于我国锦屏深地核天体物理JUNA项目的重要意义.
Abstract:
For the hydrostatic stable burning in stars,the Gamow window is well below the Coulomb barriers for the charged-particle-induced nuclear reaction involved.Such nuclear reaction occurs through the quantum-mechanics tunneling effect,and its cross section drops rapidly approaching the Gamow window.An accelerator which can provide intense beam current is thus required to directly measure the reactions at low energies.An experimental setup for low-energy nuclear astrophysics studies has been recently established at a 320 kV high-voltage platform of the Institute of Modern Physics (IMP),Lanzhou,China.The driver machine of this platform is a very strong ECR ion source employing all-permanent magnets,which can typically supply up to about 100 eμA proton,alpha and many other heavy ions,and ultimately about 30 eμA currents can be achieved at the experimental terminal.The experimental setup includes a target chamber,and the charged-particle and γ-ray HPGe detectors.This work describes the setup established,characteristics of detectors,methodologies,and test results of several reactions with known cross sections.Furthermore,some important results published are shown briefly.We believe that the experimental technologies developed and experiences accumulated at this above-ground platform will be extremely helpful for the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project in China.
首页
登录
注册
下载: