共查询到18条相似文献,搜索用时 359 毫秒
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以直线感应加速器(LIA)匹配磁场设计和束线调谐为背景,提出解决强流相对论电子束长距离、小波动、多元件磁约束的输运优化问题的数值优化办法,建立基于遗传算法的优化程序。结合束质心轨迹及束包络耦合模型,设计描述束传输半径波动大小的评价函数,采用励磁元件馈入电流为优化对象,解决LIA磁场配置组合爆炸优化问题。计算结果表明:优化程序可依据不同的初始束流,有针对性地快速给出一组符合束输运要求的励磁电流配置。研究成果为在建的LIA装置束线调谐提供一种重要的数值分析工具。 相似文献
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由于直线感应加速器束输运系统磁场准直偏差和束脉冲期间所引起的束流Corkscrew运动是导致发射度增长的重要原因之一,因而提高磁场准直精度是抑制和减小Corkscrew振幅的重要措施。机械轴的精密对中是磁轴准直及磁场误差校正的基础。 相似文献
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“神龙一号”强流脉冲加速器由72个直线感应加速腔和18个用于测试和真空泵接口的多功能腔组成。直线感应加速器的研制建造中磁轴对中偏差和聚焦磁场的自然偏差所引起的束流质心偏移轨道中心是不可避免的,由于束脉冲期间存在能散,使束流产生Corkscrew运动,导致束流品质变坏。而束脉冲期间的能散只能减小到一定水平,因此必需采取一定的措施抑制Corkscrew幅度的增长。在加速器的安装阶段,脉冲悬丝技术被应用于准直加速段聚焦磁场,并在磁轴准直测试的同时对磁场固有倾斜偏差进行初步校正。根据脉冲悬丝测试所得实验数据,采用传输矩阵法对加速段束质心轨迹进行了初步估计,计算中考虑了各加速腔聚焦磁场的倾斜和偏移误差。给出了计算结果和分析。 相似文献
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3.5 MeV 注入器是“神龙一号”直线感应加速器的束源,在注入器束流调试中,首先通过数值模拟方法,初步确定束流过聚焦和聚焦不足两种极端情况下引出线圈输运磁场峰值的变化范围;然后以注入器出口束流波形为参考,通过实验调试找到了这两种情况下引出线圈输运磁场峰值的实际配置;再通过测量束流的剖面或发射度,在这两种配置中选定一个折中的引出线圈磁场配置,并最终确定了注入器输运磁场的总体配置。经过调试完成后的注入器束流为3.6 MeV,流强为2.8 kA,归一化边发射度为1 040 mm·mrad,达到了预期的指标。 相似文献
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采用粒子模拟(PIC)方法模拟了强流电子束在薄磁透镜中的聚焦。建立了强流电子束的聚焦模型,模拟了神龙一号加速器某次实验的结果,得到的模拟结果非常接近实验值,证明采用建立的PIC模型模拟强流束经过磁透镜时的聚焦是可信的。应用此模型模拟了电子束参数(入射半径、发射度、能散度、相位角等)对焦斑直径的影响, 结果表明:在模拟条件下,电子束平行入射时最佳束包络半径位于20.0~22.5 mm;发射度和能散度对焦斑直径的影响和理论公式吻合得较好;只有入射电子束包络半径和相位角匹配时才能得到小的焦斑直径。 相似文献
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在注入器段阳极杆内不同位置进行电子束包络的测量可以为多脉冲电子束在注入器段的传输磁场配置调试提供最直接的支撑,也是研究热阴极发射性能的重要手段,测量工作具有极为重要的意义。神龙二号采用热阴极作为多脉冲电子束源的发射体,对真空的要求极高,且加热及降温周期较长,不适合频繁地破坏真空进行测量位置的调整;针对这样的特点,设计了一套可伸缩式的测量装置,结合多幅分幅相机,在不破坏真空的情况下,可以完成多个位置的束包络的时间分辨测量,在提高测量效率的基础上进一步提高了注入器的调试效率。 相似文献
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研究了周期性聚焦磁场通道中,束晕-混沌的外部磁场滑模变结构控制方法。通过选择适当的滑模函数,根据李雅普洛夫稳定性条件,推导出外部磁场的滑模变结构控制器。模拟结果表明,在控制条件下,混沌变化的束包络半径能被控制到匹配半径。将该方法应用在多粒子模型中,实施每隔一个磁场周期就调节一次磁场幅度的控制策略,可实现对初始分布为K-V分布离子束的束晕-混沌的有效控制,束平均发射度降低了80%左右,束晕强度因子变为0,束流质量得到了很好的改善,消除了束晕及其再生现象。由于外部磁场是可测和可调的物理量,控制器简单且利于实现,研究结果可为强流离子加速器中周期性聚焦磁场的设计与试验提供参考。 相似文献
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强流质子源与低能传输线(LEBT)是作为CIADS注入器的超导强流质子直线加速器的关键前端系统。目前LEBT采用双螺线管匹配结构设计,并安装有限制锥,但仍然不能避免少量H2+和H3+进入后端加速装置,这对直线加速器长期运行稳定性与可靠性会产生一定影响。为此,在LEBT加入分析磁铁对混合束(H+,H+2,H3+)进行分离再注入后端加速器腔体,将是一个有效的方案。本研究对经过带有30度分析磁铁的LEBT的强流质子束的束流品质进行了模拟与实验测量。结果表明,分析磁铁高阶磁场的影响使经过分析磁铁的强流质子束束流品质变差,并且该影响随着束流包络的增大而增大。这些结果为CIADS注入器的低能传输线设计提供了参考依据。High current proton source and the low energy beam transport(LEBT) are the key front-end systems for CIADS injector:high current proton linac accelerator. CIADS injector's LEBT adopts double solenoid matching structure, using a limit cone which can partially avoid H2+ and H3+ which injecting into the back-end linac accelerator may impact the long-term stability and reliability of the whole system. It will be an effective method to separate the hybrid ions (H+, H2+, H3+) by adding a dipole magnet at LEBT. In this article, we simulated and mesasured the high current proton beam quality behind the LEBT with a 30 degree dipole. The results show that the the proton beam quality is significantly effected by high-order magnetic fields of the dipole magnet, and the effect increases with the increase of the beam envelope. The achieved result is useful for the LEBT design of CIADS injector. 相似文献
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DAI Zhi-Yong XIE Yu-Tong LI Hong ZHANG Wen-Wei LIU Yun-Long PAN Hai-Feng ZHANG Lin-Wen DENG Jian-Jun 《中国物理C(英文版)》2009,33(9)
DRAGON-Ⅰ designed and manufactured by CAEP is a linear induction accelerator which can produce a 20 MeV-3 kA-60 us electron beam. The high performance required for the machine is determined by the beam quality and thus is greatly dependent on the accelerator alignment. In order to reduce the chromatic effect of the beam, the stretched wire technique has been developed to measure magnetic axes of the cells precisely, and the dipole steering magnets have been equipped into each cell to correct its magnetic axis misalignment. Finally, the laser tracker has been used to examine the installation error of the accelerator. In this paper, different alignment techniques and the primary results are presented and discussed. 相似文献
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The time-resolved electron beam envelope parameters, including cross sectional distribution and beam centroid position, are very important for the study of beam transmission characteristics in a magnetic field and for verifying the rationality of the magnetic field parameters employed. One kind of high time-resolved beam envelope measurement system has recently been developed, constituted of a high-speed framing camera and a streak camera.It can obtain three panoramic images of the beam and time continuous information along the given beam profile simultaneously. Recently obtained data has proved that several fast vibrations of the beam envelope along the diameter direction occur during the front and the tail parts of the electron beam. The vibration period is several nanoseconds. The effect of magnetic field on the electron beam is also observed and verified. Beam debugging experiments have proved that the existing beam transmission design is reasonable and viable. This beam envelope measurement system will establish a good foundation for beam physics research. 相似文献
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GAOYuan LUOXiao-Shu FANGJin-Qing WENGJia-Qiang 《理论物理通讯》2004,42(1):64-68
In this paper, the parametric adaptive method for controlling the beam halo-chaos in the periodic focusing channels of high-current proton linacs is presented. The study of proton beam halo-chaos based on controlled beam envelope equation and the results of particles-in-ceU simulations for macro-particle beam show that the proton beam chaotic envelope as well as the beam rsm radius can be controlled to the beam matched radius using this method. For the Kapchinskij-Vladimirskij (K-V) distribution of initial proton beam, all statistical physical, quantities of the beam halo-chaos are largely reduced. This control method has an advantage of the control halo-chaos since the exterior magnetic field as controlled parameter can be rather easily adjusted in the periodical magnetic focusing channels for the experiment. 相似文献