基于ECR离子源的径向引出型D-D中子发生器基本特性研究

Because the D-D neutron generator has the advantages of small volume and high safety, the high yield D-D neutron generator has a potential application in neutron capture cancer and mobile thermal neutron radiography. Due to the limitation of the beam intensity of the conventional axial extraction D-D neutron generator, the neutron yield is difficult to be further improved. This project presents a D-D neutron generator based on the assumption of radial extracted ECR ion source, using a magnetic field structure for the ECR ion source discharge and the radial zone magnetic insulation at the same time. In such a method, it is to solve the problem of electron suppression when the beam is intense and the extraction area is small. This project is to study the discharge characteristics of the ECR ion source and the radial extraction characteristics when the extraction region is magnetically insulated, to obtain a magnetic field structure satisfies the above conditions, and to solve the discharge and the secondary electron suppression problem of the radial extraction D-D neutron generator.

由于D-D中子发生器体积小、安全性高，高产额D-D中子发生器在中子俘获治癌和可移动热中子照相方面有着很强的应用潜力。由于传统轴向引出型D-D中子发生器的束流强度受到限制，其中子产额很难得到进一步提升。本项目提出了一种基于ECR离子源的径向引出型D-D中子发生器设想，利用一个磁场结构同时使ECR离子源放电和使径向引出区实现磁绝缘，从而解决小空间内强流束引出时的二次电子抑制问题。针对此设想存在的一些未知因素，本项目对满足径向引出区磁绝缘条件时ECR离子源的放电特性研究和径向引出特性进行研究，拟获得同时满足上述条件的磁场结构，为基于ECR离子源的径向引出型D-D中子发生器解决放电和二次电子抑制等问题奠定基础。

本项目提出了一种基于ECR离子源的径向引出型D-D中子发生器设想，利用一个磁场结构同时使ECR离子源放电和使径向引出区实现磁绝缘，从而解决小空间内强流束引出时的二次电子抑制问题。对满足径向引出区磁绝缘条件时ECR离子源的磁场结构进行了设计和优化。对径向引出ECR离子源的放电特性进行了研究，获得了微波耦合方式、永磁体结构、微波功率、进气量等因素对其放电特性的影响。对该ECR离子源的束流径向引出特性进行了研究，获得了磁绝缘条件下的束流引出、二次电子抑制和靶散热效果。