低温永磁波荡器过冷液氮冷却系统的设计

低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)是目前插入件技术发展的主要方向之一,其利用一些永磁材料,如钕铁硼(Nd Fe B)或镨铁棚(Pr Fe B)的磁场性能在低温下明显高于室温的特性来提高波荡器性能和光源束流品质,工作温区为50-150 K,需要冷却系统的冷却。CPMU冷却系统主要包括过冷液氮冷却系统和磁体阵列冷却回路。本文介绍了上海光源(Shanghai Synchrotron Radiation Facility,SSRF)CPMU过冷液氮冷却系统的设计方案和设计参数,进行了系统主要热负载的分析;对冷却系统中关键设备之一的过冷换热器进行了设计,并计算分析了过冷氮流经CPMU冷却系统的全程阻力损失,为系统另一关键设备液氮泵的选型提供依据。对CPMU过冷液氮冷却系统进行的在线测试表明,该设计满足CPMU样机的冷却需求。     

北京正负电子对撞机重大改造工程中超导四极磁体传热与流动计算

超导四极(SCQ)磁体是北京正负电子对撞机重大改造工程(BEPCⅡ)的关键设备之一。本文对SCQ磁体恒温器进行稳定运行状态下传热和流动计算。计算得到了磁体在低温下的热负荷以及磁体恒温器内各组成部分的温度分布，并在此基础上，提出减小SCQ磁体热负荷的方法。比较计算了SCQ磁体采用超临界和过冷液氦两种冷却方式对磁体稳定运行的影响。     

上海光源新型波荡器EPU200磁结构的机械设计及力学分析

跟据用户的实验要求,本项目为上海光源中产生低轴功率密度的同步辐射光设计了新型波荡器EPU200(Elliptically Polarized Undulator)。EPU200是首台拥有8排磁化块、可以产生椭圆极化辐射并降低轴功率密度的纯永磁波荡器。其8排磁排列安装在4根铝梁上,每个磁化块固定件上安装两块磁化块,其磁结构的机械结构和安装十分复杂。磁结构对波荡器的品质有很大影响,首先设计EPU200的磁结构的机械结构,根据磁化块的排列通过Radia程序计算出磁化块的最大受力,并通过ANSYS Workbench对磁结构进行力学分析,得出该结构中磁化块的位置变形量,从而验证该机械结构的可行性。     

上海光源真空内波荡器积分场垫补中模拟退火算法的应用

上海光源真空内波荡器(IVU-25)系我国第一台真空内波荡器,由我所设计和研制。该波荡器采用混合型磁体结构,共80个磁周期,周期长度25mm,最小工作磁间隙7mm,最大峰值磁场强度0.94T。波荡器磁块的剩磁离散性及安装机械公差等因素会引起积分场误差从而影响储存环工作状态。在波荡器积分场多极分量垫补过程中,我们用模拟退火算法优化一次积分场分布来垫补多极分量,结果表明积分场多极分量均达到设计指标。     

PSD位置测量系统在波荡器磁场测量中的应用

位置敏感探测器(Position Sensitive Detector,PSD)是一种基于横向光电效应(x和y方向)的光电位置敏感器件,可直接探测到入射光斑的能量中心位置,在波荡器磁测中可用于获得霍尔探头测量过程中的横向位置变化。为了在狭小或封闭空间内实现对波荡器(尤其是真空内波荡器)磁场进行高精度的测量,我们设计并搭建了测试系统,对导轨直线度(x和y方向)进行了测量。实验结果表明,该位置测量系统具有5μm的测量精度,可以满足霍尔探头在波荡器磁测过程中的位置精度要求。     

热真空永磁流量计的热工和电磁设计与分析

利用ANSYS CFX和MAXWELL软件对中国原子能科学研究院设计的热真空永磁流量计进行了热工和电磁分析，该流量计用于测量地面试验回路中真空条件下1 000℃高温液态碱金属的流量，给出了流量计的温度云图和磁感应强度分布图，并得到了输出电压与流速的基本关系。结果表明：使用三层隔热屏阻隔降温，冷却铜块接触冷却，可将磁钢温度控制在100℃以下；选用钕铁硼和钐钴永磁体，均可输出毫伏级电信号，而用高磁能积的钕铁硼可使流量计实现更小的重量和体积，确保了永磁流量计在热真空条件下运行的可靠性。     

可变椭圆极化波荡器EPU10.0的传动控制

可变椭圆极化波荡器EPU10.0是一种可产生多种极化模式相干太赫兹辐射的波荡器。EPU10.0的主要特点是波荡器内的磁块分上下各两排，上下气隙固定，一对对角线永磁块排列固定，另一对可独立做纵向移动，移动重复定位精度小于0.01mm。对该波荡器的磁测结果显示：在水平线极化和圆极化模式下，磁场的两个横向分量的一、二积分分别为0.012T•cm和0.7T•cm²，达到了设计指标。     

上海光源插入件光束线白光狭缝设计

上海光源是第三代同步辐射装置,第一期工程拟建造7条光束线中有5条选用插入件光源,其中,三条由波荡器(Undulator)引出,两条由扭摆器(Wiggler)引出。插入件光源产生高功率同步辐射,会给插入件光束线部件设计带来极大的挑战。为此,我们为插入件光束线设计了新型L形白光狭缝,本文主要介绍了该白光狭缝设计。     

CFETR纵场超导磁体CICC导体低温冷却设计与分析

纵场磁体中导体低温超导性对整个托卡马克装置磁体系统的稳定具有重要作用。对纵场磁体的低温冷却系统进行热分析,确定线圈排布匝数、纵场磁体中心冷却孔以及盒壁内侧冷却孔的质量流速,并计算液氦在导体中心冷却孔流动时的沿程压降。分析结果表明:同种工况不同线圈排布磁体组件温差值各不相同,经过对比分析,纵场磁体选用154匝线圈排布方案。为确保纵场线圈盒体温度与导体铠甲的温度分别在20 K与5 K范围之内,线圈盒内侧壁面冷却孔质量流速为3.6 g?s~(-1),纵场磁体线圈导体内中心冷却孔质量流速为9.5 g?s~(-1),液氦流动沿程压降为1.72×10~5Pa。     

EAST托卡马克绝缘子低温力学性能理论及实验分析

复合材料绝缘子是EAST托卡马克磁体系统的关键部件，担负着整个磁体系统低温冷却回路与高压部件的对地绝缘作用。运行中，绝缘子在低温下要承受较高的内压及电压，保持绝缘子在低温状态下的机械整体性是运行安全的必要保证。从整个装置的使用安全考虑，有必要对绝缘子低温力学性能作全面分析。本工作首先对绝缘子的机械低温力学性能进行理论分析，然后通过设计的低温力学实验验证理论分析结果。以此为基础，对装置中的损坏绝缘子进行分析，确定损坏原因。     

Structural analysis and optimization for ITER upper ELM coil

ITER ELM coils are used to mitigate or suppress Edge Localized Modes (ELM), which are located between the vacuum vessel (VV) and shielding blanket modules and subject to high radiation levels, high temperature and high magnetic field. These coils shall have high heat transfer performance to avoid high thermal stress, sufficient strength and excellent fatigue to transport and bear the alternating electromagnetic force due to the combination of the high magnetic field and the AC current in the coil. Therefore these coils should be designed and analyzed to confirm the temperature distribution, strength and fatigue performance in the case of conservative assumption. To verify the design structural feasibility of the upper ELM coil under EM and thermal loads, thermal, static and fatigue structural analysis have been performed in detail using ANSYS. In addition, design optimization has been done to enhance the structural performance of the upper ELM coil.     

SSRF波荡器的渡越辐射特性研究

通过解析分析和数值模拟计算,对上海同步辐射装置(SSRF)波荡器U9.0在红外及远红外波段(波长范围8200μm)的渡越辐射谱通量密度角分布、亮度等特性进行了研究,并探讨了电子束发射度、能量散度及波荡器磁场误差对渡越辐射谱亮度的影响。结果表明,SSRF U9.0的红外及远红外渡越辐射通量密度最高可达351013Photons/(smrad2BW),收集角φ=0.23mrad,且通量密度随电子上的发射度、能散和波荡器磁场误差等的变化很小。     

上海软X射线装置中纯永磁移相器的积分场垫补

X射线自由电子激光(Free-electron Laser,FEL)达到饱和功率输出时所需要的波荡器总长度为数十米甚至上百米,目前国内外研制的波荡器只能分段加工,且每段长度一般在5 m以内。为了保证两相邻波荡器间辐射光的相位相互匹配,通用的设计是在相邻波荡器之间增加移相器。移相器的加入不应对电子束流产生影响,其产生的磁场沿束流方向的一二次积分必须达到技术要求。由于移相器较短,二次积分较小,可不予考虑。在不考虑永磁块非线性的基础上,导出了纯永磁移相器的磁场一次积分以及调整移相器中某些磁化块的高度和倾斜角度产生的磁场一次积分变化量的解析表达式。利用这种方法对上海软X射线自由电子激光装置中的5台移相器做积分场垫补,使得每台移相器的磁场一次积分在好场区内都小于20 Gs·cm,满足工程设计要求。     

波荡器磁场误差对其自发辐射的影响模拟研究

波荡器由多个单磁块组成,磁块不可避免的剩磁离散性和尺寸离散性是引起波荡器磁场误差的根本原因。波荡器磁场误差将影响波荡器自发辐射谱的质量。本文给出一种新的单磁块磁场、波荡器磁场及自发辐射的模拟方法,从单磁块磁场模拟人手,使用正态分布随机数发生器产生多组不同剩磁或者不同尺寸的单磁块,再由这种方式产生的单磁块组成波荡器,然后计算自发辐射,从而研究波荡器磁场误差对自发辐射的影响。     

Tunable biasing magnetic field design of ferrite tuner for ICRF heating system in EAST

Ion cyclotron range of frequency(ICRF) heating has been used in tokamaks as one of the most successful auxiliary heating tools and has been adopted in the EAST. However, the antenna load will fluctuate with the change of plasma parameters in the ICRF heating process. To ensure the steady operation of the ICRF heating system in the EAST, fast ferrite tuner(FFT) has been carried out to achieve real-time impedance matching. For the requirements of the FFT impedance matching system, the magnet system of the ferrite tuner(FT) was designed by numerical simulations and experimental analysis, where the biasing magnetic circuit and alternating magnetic circuit were the key researched parts of the ferrite magnet. The integral design goal of the FT magnetic circuit is that DC bias magnetic field is 2000 Gs and alternating magnetic field is±400 Gs. In the FTT, E-type magnetic circuit was adopted. Ferrite material is Nd Fe B with a thickness of 30 mm by setting the working point of Nd Fe B, and the ampere turn of excitation coil is 25 through the theoretical calculation and simulation analysis. The coil inductance to generate alternating magnetic field is about 7 m H. Eddy-current effect has been analyzed, while the magnetic field distribution has been measured by a Hall probe in the medium plane of the biasing magnet. Finally, the test results show the good performance of the biasing magnet satisfying the design and operating requirements of the FFT.     

Design of Tokamak ELM Coil Support in High Nuclear Heat Environment

In Tokomak, the support of the ELM coil, which is close to the plasma and subject to high radiation level, high temperature and high magnetic field, is used to transport and bear the thermal load due to thermal expansion and the alternating electromagnetic force generated by high magnetic field and AC current in the coil. According to the feature of ITER ELM coil, the mechanical performance of rigid and flexible supports under different high nuclear heat levels is studied. Results show that flexible supports have more excellent performance in high nuclear heat condition than rigid supports. Concerning thermal and electromagnetic （EM） loads, optimized results further prove that flexible supports have better mechanical performance than rigid ones. Through these studies, reasonable support design can be provided for the ELM coils or similar coils in Tokamak based on the nuclear heat level.     

Sm(Co0.82，Fe0.1，Cu0.06，Zr0.02)7.2永磁材料中子辐照后退磁效应的计算分析

运用于反应堆的永久磁铁处于中子辐照的恶劣环境,而辐照将会影响永久磁铁的性能。为评估中子辐照对永磁铁性能的影响程度,利用欧洲活化计算系统EASY-2007对耐2a中子辐照的Sm(Co_0.82,Fe_0.1,Cu_0.06,Zr_0.02)_7.2永磁铁进行辐照计算,通过分析元素成分的变化来推测磁性能的衰减情况。结果表明,辐照后的永磁铁中Fe元素含量变化不大,而Sm元素含量大幅降低,这使得矫顽力降低严重。     

Thermo-mechanical analysis of the thermal shield for ITER magnet feeder

The thermal shield for ITER magnet feeder plays the role of preventing thermal radiation from the warm components to the cool superconductor and supercritical helium system. Heat loads were calculated for thermal analysis, then finite element model was established by ANSYS code. Thermal analysis was performed in order to check the temperature distribution and pressure drop of the thermal shield under normal operation state. Different materials (steel or aluminum) for the thermal shield were also checked. Thermal stress analysis was performed based on the results of thermal analyses. Compared analysis results with design criteria, it is demonstrated that the results of the simulation are within allowable design requirements and the design scheme can be applied to the detailed design.