【作者】 秦斌；

【导师】 樊明武；

【作者基本信息】 华中科技大学 ， 控制理论与控制工程， 2007， 博士

【摘要】 紧凑型回旋加速器由于具有灵活和经济特点,是核物理、固态物理等基础研究的重要工具,同时,广泛应用于PET(Positron Emission Tomography)诊断、质子治疗、同位素生产和工业辐照等应用领域。虚拟样机作为一种新兴的基于虚拟现实和数值仿真的数字化技术,目前在复杂制造领域得到了应用。将虚拟样机技术引入到回旋加速器的设计中,有助于产生创新方案、降低工程风险。本文研究了在虚拟样机的集成环境下,以加速器束流动力学为工具,所开展的紧凑型回旋加速器主磁铁和轴向注入系统中相关部件的物理设计,并以实验验证了虚拟样机数值模拟方法的有效性。作为全文的理论基础,本文首先对回旋加速器束流动力学作了回顾,包括粒子的横向运动与纵向加速运动及其稳定性,着重讨论了基于数值方法的回旋加速器平衡轨道、粒子滑相和横向自由振荡频率的分析与计算。在此基础上,提出了一种基于对电磁场中粒子运动方程进行数值积分,以跟踪单粒子或束流相空间内多粒子轨迹并进行相关束流动力学分析的算法,设计并实现了了采用该算法的PTP(Particle Tracking Package)程序内核与人机界面,并将该程序的计算结果同TRIUMF实验室的CYCLOP程序作了比对。PTP作为一个分析工具,在论文中加速器各部件的设计中均有应用。主磁铁是紧凑型回旋加速器中造价最高的部件,对设计要求极严,要求满足粒子加速的等时性和横向聚焦条件,避免危险的共振线穿越。论文讨论了主磁铁设计上的主要考虑因素,研究了在集成环境下,利用有限元磁场计算与束流动力学分析的协同化作业进行磁铁设计与优化的方法。轴向注入系统是提高注入效率和束流强度的关键,本文以一台16 MeV回旋加速器为实例,开展了基于TRACE3D程序的轴向注入的光路设计,并研究了螺旋偏转板解析与数值分析方法。本文提出了一种基于Python脚本语言和混合编程方法的回旋加速器虚拟样机集成环境方案,并进行了实现。该方案能够满足虚拟样机设计平台中异构性组件的集成需求,同时具有灵活和易于扩展的特性。物理样机上的实验及数据比对是验证虚拟样机有效性的重要手段。在论文的最后部分,介绍了作者参予的两项实验研究:其一为日本京都大学研究用反应堆实验室FFAG(Fixed Field Alternating Gradient)注入环的束流测量实验;其二为中国原子能科学院CYCIAE100回旋加速器中心区实验平台主磁铁测量实验。这两项实验的结果分别验证了束流动力学和磁铁有限元分析在数值模拟上的预测能力和准确性。更多还原

【Abstract】 The compact cyclotron is a very flexible and economical accelerator, which is not only an important tool for fundamental science such as nuclear and solid-state physics research, but also widely employed in PET (Positron Emission Tomography) system, proton therapy, isotopes production and industrial radiation. We applied VP (Virtual Prototyping) technique in the design and development processes of compact cyclotrons, which conduces to generating innovational schemes and reducing risks. With the guide of beam dynamics theory, this thesis describes the design study for the main magnet, the axial injection system and some related components of cyclotrons in the integrated VP environment. The experimental results agree well with the numerical simulation of magnet fields and beam behavior.First of all, the basic beam dynamics including transverse and longitudinal motion with their stability underlying compact cyclotrons are reviewed. The numerical analysis and calculation method of equilibrium orbits, phase shift and tune in cyclotrons is discussed.With Runge-Kutta integration on particles motion equations, we can obtain beam particles trajectories and perform related beam dynamics analysis. Base on this method, a code named PTP (Particle Tracking Package) is designed and implemented with C++ and Python languages. The results of PTP agree well with the TRIUMF code CYCLOP.The main magnet is the most expansive part in cyclotrons, which has stringent design tolerances. The magnetic field distribution should fulfill requirements of isochronisms and transverse focusing of the beam, as well as to avoid dangerous resonance crossing. The main design considerations of the main magnet are summarized. And an automated magnet design and optimization method with the collaboration between beam dynamics analysis and magnet FEM (finite elements method) calculation is studied.The axial injection system is the key facility of achieving high intensity beam and high transport efficiency. This thesis studied the optics design of a 16 MeV cyclotron axial injection line with the TRACE3D code. The analytical and numerical design study of the spiral injector is described.The VP integrated platform is a large-scale software and has numerous loose-coupled components. A pythonic approach and implementation with heterogeneous feature is proposed, which achieves a combination of code efficiency, flexibility and compactness.Experimental study of physical prototypes is very important to validate numerical results in VP environment. Two experiments are introduced. One is the beam measurement of the Injector ring of FFAG Complex in KURRI. The other is the magnet field measurement of a 10 MeV prototype cyclotron in CIAE. The experiment results show good agreement with the numerical simulation of beam dynamics and magnet field.更多还原