基于NdFeB的小周期错列波荡器物理模型研究

X-ray free electron laser facility is an important platform of contemporary scientific research, but has the problems of large scale and high cost. So, the compact XFEL becomes a research hotspot and the reduction of undulator period is one of the important directions of the development of the compact XFEL. Although various types of undulators, such as superconducting undulator, in-vacuum undulator, cryogenic permanent magnet undulator and microwave undulator et. al., have been proposed and developed, it is still difficult to meet the requirements of mini-period and high field strength. The peak field of solenoid-derived undulator with 10 mm period is up to 1.08 T, and shows great application value. But low temperature required by superconducting solenoid limits its popularization and application. In this project, seeing the high magnetic properties of NdFeB permanent magnetic material at room temperature, it is proposed to replace the superconducting solenoid by NdFeB, and we will fulfill the following research contents: establishment of physical model of mini-period NdFeB-derived staggered undulator, research on the magnetic field rules in the physical model, verification of the physical model and the magnetic field rules and feasibility discussion for the compact XFEL. If the undulator physical model can be established successfully, a new scheme for reducing the undulator period will be provided, which will promote the development of compact XFEL.

X 射线自由电子激光装置是当代科学研究的重要平台，但有规模巨大和成本高昂等问题，因此紧凑型XFEL成为一个研究热点，减小波荡器周期是紧凑型XFEL发展的重要方向之一。虽然已经提出并发展了超导波荡器、真空波荡器、低温波荡器和微波波荡器等多种类型的波荡器，但是依然难以同时满足小周期和高场强的要求。基于螺线管的错列波荡器在10 mm周期下，峰值场强可高达1.08 T，具有很大应用价值，但是超导螺线管所需的低温条件限制了其推广应用。鉴于NdFeB永磁材料在室温具有优良的磁性能，本课题提出用NdFeB材料来取代超导螺线管的思路，并完成以下研究内容：建立基于NdFeB永磁材料的小周期错列波荡器物理模型；研究该模型中的磁场规律；通过实验来验证模型和磁场规律的正确性；探讨该模型用于紧凑型XFEL的可行性。这一波荡器物理模型若能成功建立，将提供一种减小波荡器周期的新方案，对XFEL 装置的小型化有推动作用。

波荡器是XFEL装置的重要部件之一，其周期长度和电子束能量一起决定了辐射波长，并且周期越短辐射波长越短，减小波荡器周期可以减小XFEL装置的电子能量，从而有助于其小型化。超导螺线管错列波荡器是一种已有的小周期波荡器，但其需要超导螺线管，具有成本高加工难的问题。本项目在基于超导螺线管错列波荡器的基础上，提出了基于NdFeB的小周期错列波荡器。项目完成了如下研究内容：设计了基于NdFeB的小周期错列波荡器永磁磁路和软磁磁路，分别得到了永磁磁路和软磁磁路的解析表达式，并研究了磁路参数对磁场的影响规律，分析了永磁材料退磁效应和软磁材料饱和效应对磁场的影响；联合使用遗传算法和RADIA磁场计算程序，对基于NdFeB的小周期错列波荡器进行了优化；研究了基于NdFeB的小周期错列波荡器磁场的调节方法；进行了验证平台的搭建和磁场点测台的升级改造，完成了基于NdFeB的小周期错列波荡器物理模型验证；分析了基于NdFeB的小周期错列波荡器在XFEL装置上应用的可行性。重要结果如下：实现了4 mm波荡器间隙和10 mm周期下，横向峰值磁场约0.34 T，并且在2 mm波荡器间隙和10 mm周期下，横向峰值场强达到了约0.79 T。通过本项目，建立了一种基于NdFeB的小周期错列波荡器物理模型，为基于加速器光源的波荡器提供了一种新方案。

内容获取失败，请点击重试