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新型激光驱动储存环物理优化设计研究

Research on Optimization and Design of Advanced Laser-driving Storage Ring

作者:潘志龙
  • 学号
    2015******
  • 学位
    博士
  • 电子邮箱
    pan******com
  • 答辩日期
    2020.05.24
  • 导师
    唐传祥
  • 学科名
    核科学与技术
  • 页码
    116
  • 保密级别
    公开
  • 培养单位
    032 工物系
  • 中文关键词
    逆康普顿散射,稳态微聚束,储存环,激光驱动,纵向优化
  • 英文关键词
    ICS,SSMB,storage ring,laser-driving,longitudinal dynamic optimization

摘要

基于电子储存环的同步辐射光源从同步辐射在1947 年被第一次观测到开始,已经历经了四代的发展。第一代的同步辐射光源主要服务于高能物理实验,同步辐射是作为寄生物从偏转磁铁中引出。第二代同步辐射光源是专门为同步辐射用户而设计,光源亮度提高了2 个量级。第三代同步辐射光源中,束团发射度得到了进一步的优化,且插入件被大量引入用来优化辐射的亮度和相干性。第四代同步辐射光源提出衍射极限环的概念,将使储存在环内的电子束横向尺寸达到衍射极限,以大大提高出射光束的亮度。储存环的发展提供了具有宽能谱、高亮度、高偏振等优良性质的光源,为原子物理、生命科学、相衬成像、材料科学、化学、医学等领域提供了优良的研究平台,具有十分重要且不可替代的作用。近年来,将激光驱动与电子储存环相结合的先进光源的研究越来越受到重视,它们利用储存环中的电子束团与激光相互作用,产生高品质的光束,这些先进光源对储存环的设计提出了新的要求。本论文的工作主要围绕这类激光驱动储存环的环物理,以及储存环的设计、优化、动力学模拟而展开,包括利用逆康普顿散射(ICS) 产生高亮度伽马射线源的储存环(ICS 储存环)和利用环内稳态微聚束(SSMB) 产生高功率极远紫外激光(EUV) 的储存环(SSMB 储存环)。ICS 储存环的设计主要在于光源产额的优化。本文首先介绍了逆康普顿散射物理过程,以及该过程在储存环内对电子束统计平衡参数的影响。在综合考虑束内散射效应(IBS 效应)之后,本本给出了优化的磁铁聚焦结构(lattice)设计,以最大化? 射线产额。基于该lattice,利用编写的模拟程序,本文模拟了逆康普顿散射作用下储存环内电子束平衡参数的变化,同时模拟了不同激光参数下电子束的损失情况。SSMB 储存环侧重于纵向空间的优化。为了实现稳态微聚束以产生高功率的EUV 光源,在纵向强聚焦的设计中,需要保证纵向束团长度小于100 nm 的电子束团在储存环内稳定储存,这比国际上现有的储存环内电子束团长度小了3-4 个量级。本文从原理上提出一种可行的lattice 设计方案,全局和局部动量压缩因子被同时优化。非线性动力学和非线性设计也是重点讨论的对象并得到了较好的优化。对设计出的lattice 进行的单粒子束流动力学模拟表明,储存在环内的稳定电子束团长度为40 nm 左右,满足需求。该结果初步表明,在储存环内实现稳态微聚束并且产生kW 量级的EUV 辐射从储存环物理上是具有可行性的。

After the first observation of synchrotron radiation in 1947, tAfter the first observation of synchrotron radiation in 1947, the electron storage ring based synchrotron radiation light source has developed for four generations. The first generation synchrotron radiation light sources are mainly served for the experiments of high-energy physics, extracting the synchrotron radiation from bending magnets as parasite. The second generation synchrotron radiation light sources are exclusively designed for synchrotron radiation users, whose brightness is improved by about 2 orders of magnitude. In the third generation synchrotron radiation light sources, the brightness of light source are optimized furthermore, and large number of insertion devices (for example, undulator) are introduced for optimizing the brightness and coherence of radiation. In thenext generation, diffraction limited storage rings are proposed, in which the transverse size of electron beam reaches the diffraction limit, resulting in the significant improvement of brightness for radiating beam. The development of storage ring produces many light sources with excellent properties in terms of wide spectrum, high brightness, and high polarization, which provides the great research platform for many fields, such as atomicphysics, life sciences, contrast imaging, material science, chemistry, and medical science, and playing an important and irreplaceable role.In recent years, the researches on the advanced light source by combining the laser-driving and electron storage rings have been increasingly emphasized, which can producelight source with high quality by utilizing the interaction of electrons and laser in storage ring. Those advanced light source put forward new requirements for storage ring design.This paper is mainly concerned with the physics, lattice design, optimization and dynamic simulation of the advanced laser-driving storage rings, in terms of the storage ring togenerate high brightness ?-ray light source based on inverse Compton scattering technique (ICS storage ring) and the storage ring to generate high average power EUV radiation by steady-state microbunching (SSMB storage ring).The point of ICS storage ring design is optimizing the yields of light source. We introduce the inverse Compton scattering process first, whose impact on the statistical equilibrium parameters of electrons in storage ring also provided. A ring lattice are obtained to gain an optimal yields of ? photon based on the brightness calculation in the ring, intra-beam scattering (IBS) also considered. We code a simulation program to simulate the change of equilibrium parameters for marcoparticles in this optimal lattice, and simulatethe loss condition of electrons by changing the laser parameters (different yields of light source).The optimization for SSMB storage ring is focusing on the longitudinal dynamics. In order to generate high average power EUV radiation by SSMB, the requirements for bunch length of the electron beam stored in the ring should be under 100 nm, which is shorter than the bunch length in existing storage rings by 2-3 orders of magnitude. A feasible lattice design is proposed, while an approach of minimizing global momentum compaction factor and local momentum compaction factor is put forward. The nonlinear dynamics and nonlinear design are also discussed to get an optimal solution. The dynamic simulation of macro-particle indicates that the bunch length of electron beam stored in this lattice is about 40 nm, while only single-particle effects is considered. The results preliminarily indicate that it is possible to achieve the SSMB and generate kW level EUVradiation from the aspect of storage ring physics.