【作者】 王荣；

【导师】 裴元吉；

【作者基本信息】 中国科学技术大学 ， 核技术及应用， 2006， 博士

【摘要】 本论文首先介绍了目前国家同步辐射实验室对极短(ps量级)电子束团宽度测量装置的需求。归纳、讨论了国际上针对极短电子束团测量的几种基本思路。阐明了一种新型测量思路——时间—能量转换法(散能法)研究的意义以及主要解决的问题。 以现有微脉冲束流电子枪(MPG)装置产生的电子束团为测量对象，开展了散能测量系统的设计工作。现有微脉冲电子枪MPG装置产生的电子束团动能大概在300KeV，初始能量分散很小(＜0.1％)，峰值流强可达为10A～100A，束团宽度在ps量级上。通过利用束流动力学数值计算软件Parmela对这样的电子束团进行计算分析发现，束团间存在强烈的空间电荷作用将严重破坏束团性能，使它无法直接适用于散能测量。提出在MPG后端直接与盘荷波导结构相连，对MPG电子进行加速，减弱空间电荷作用影响。经过加速后的电子也将进入另一盘荷波导结构受到散能作用。 以电子动能300KeV、初始能量为0.1％、峰值流强为10A的ps量级的MPG电子束团为测量对象，提出了包括加速、散能、能量分析等过程在内的整套散能测量方案。在充分理解束流动力学原理的基础上，利用理论公式编写程序完成了加速用盘荷波导结构、散能用盘荷波导结构、聚焦系统、能量分析系统等基本设计工作。利用Parmela程序对电子在上述结构参数下确定的测量系统中的运动进行了模拟，并且据此对这些结构参数进行必要的修正，最终确定上述几种结构的物理参数。利用Parmela程序对不同的电子束团不同条件下在测量系统中的运动进行了模拟计算，为将来的调试工作提供了依据。 就实际情况确定了二极分析磁铁的物理参数，从理论上对磁铁的几何结构参数作了初步计算。分别利用Mafia、Opera程序对磁铁进行数值计算，确定了磁铁的加工尺寸。完成了二极磁铁的加工。利用国家同步辐射实验室的现有磁测平台进行了磁场测量，将测量结果与数值计算结果进行比较，展现了Mafia、Opera程序在二极磁铁设计中的应用效果。 提出了一种新的基于Microwave Studio的盘荷波导耦合器的设计方法。对加速段、散能段进行了冷测工作，并给出了测量参数。更多还原

【Abstract】 The thesis described the need for the measurement of the length of pico-second electron bunch. Several typical measurement methods for it have been given and discussed here. A novel way by means of time-energy conversion process was proposed, and the meaning for developing it was discussed.For measurement of the length of the electron bunch produced by the existing micro-pulse gun (MPG) device in NSRL, the design and construction work for the measurement system has been done. The electron bunch form the MPG in NSRL has the following parameters: the kinetic energy is about 300keV, low energy dispersion (about 0.1%), the peak current is about 10A～100A, the length of electron bunch is in pico-second. With the help of "Parmela", the strong space charge force would distort the original electron bunch. To such electron bunch its length could not be got by time-energy conversion measurement. In order to overcome it, an accelerating structure (so called "accelerating section") was connected with the MPG to offer the electrons extra energy to weaken the space-charge-effect. Another accelerating structure (so called "time-energy conversion section") was used to convert the electron bunch to energy just behind the first one.For such an electron bunch from MPG defined before, an entire measurement system has been discussed, including accelerating process, time-energy conversion process, energy analysis, and so on. With the knowledge of beam dynamics theory, the code has been edited to get the original parameters of disk-loaded structure, focus system and energy analysis system. And then we simulated the motion of the electron bunch in the measurement system with the original parameters so as to correct the original parameters by "Parmela".We defined the physics property of dipole, and got the original structural parameters by theory formula. The three-dimension simulation of dipole to find the final structural parameters was finished by Mafia and Opera respectively. We更多还原