共查询到20条相似文献,搜索用时 31 毫秒
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由于束流的传输效率对射频四极场加速器(RFQ) 中射频场的分布极其敏感,所以在RFQ 的运行过程中不再采用传统的调谐器调谐RFQ。水冷调谐的方法基本上不影响RFQ 射频场的分布,所以适用于RFQ 的调谐。中国科学院高能物理研究所为C-ADS、CSNS 预研RFQ 项目开发建造了一套水冷调谐系统,使用RF 相位差作为控制量进行RFQ 水冷调谐,相位差的控制精度达到了1°运行结果显示该系统满足了RFQ 的调谐需求。介绍了该系统的水冷系统、调谐控制系统和一些运行经验。Since the beam transmission of a Radio Frequency Quadrupole(RFQ) Accelerator is very sensitive to the field profile, the ordinary frequency tuning method by the local movable tuner is no more adopted in an RFQ operation. The tuning method by controlling cooling water temperature is widely adopted to tune the RFQ due to the less affect on the RFQ field profile. A Resonance Control Cooling System (RCCS) is developed and commissioned for the 973 RFQ,which is a R&D project for C-ADS and CSNS RFQ at IHEP. This system adopts the RF phase difference as control variable to tune the RFQ. The control accuracy of the RF phase difference is about 1°. The running of the 973 RFQ shows that the RCCS works very well and fully satisfies the operation requirement of the RFQ. In this paper, the water skid, resonance control system of the RCCS and the operation experiences will be presented. 相似文献
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RFQ (射频四极透镜) 是直线加速器中最重要的前级聚焦加速结构,其工作模式下束流孔中的电场四极对称性是保证束流品质及加速效率的关键。为了解决其各自存在的工作模式下四极场的不对称问题,分别对四杆型RFQ 和四翼型RFQ 的结构和模式谐振特性做了研究。针对四翼型RFQ,模拟显示双端口对称耦合的方式从抵消二极模式和提高结构对称性两方面来达到削弱工作模式下的场分布中二极量的目的,对一个1 m段四翼RFQ 模型腔的测量证实了双端口对称耦合抵消腔内二极模式的有效性;针对四杆型RFQ 的二极场,以SSC-Linac 项目的RFQ 为原型,利用三维模拟计算软件CST-MWS 进行模拟,通过改进支撑板的结构并调整参数,完全地消除了工作模式下的极间二极场,且理论上此种改进方法对支撑板结构的四杆型RFQ 均有效。Radio Frequency Quadruple(RFQ) is the most important front-end acceleration structure in linear accelerators.It can focus and accelerate beam in longitudinal and transversal direction, simultaneously. Symmetric of electric field in acceleration aperture is very important for the beam dynamics. To an idea RFQ, there is only quadruple electric field in the acceleration aperture. The dipole field in aperture is harmful and need be as small as possible. The methods to reduce it are studied in a four-rod RFQ and a four-vane RFQ in the article ndependently. To a four-vane RFQ, the symmetrical double-port couplers are employed to counteract the neighboring dipole modes. The availability is confirmed by the simulation with the 3-D Finite Element tool, CST-MWS. And it is also observed by measuring a model-cavity with a symmetrical double-port couplers. To a four-rod RFQ, a new structure of stems is proposed to reduce the dipole mode.Taking the RFQ for the SSC-LINAC project as example, the dipole mode contributions to the electric filed is completely eliminated by selecting stem’s parameters carefully. It is confirmed by the simulation of CST-MWS. heoretically, this method is independent with the frequency of an RFQ and serves for all RFQs with 4-rod or 4-wane structure. 相似文献
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介绍了单j壳的球形平均场加几何四极-四极和标准对力模型的量子相交叉行为。在单j=15/2的壳内,计算了随模型控制参数变化的多个物理量如低激发能级、激发态间重叠积分、低激发态间的B(E2)比值和电四极矩比值。结果显示,在类转动到对激发相的演化中,多个物理量在交叉区存在非常明显的变化,如B(E2;41 → 21)/B(E2;21 → 0g),B(E2;42 → 21)/B(E2;21 → 0g)等,并且这些变化在核子数达到半满壳时尤为显著。此外,尽管当j较小时,由几何四极-四极相互作用得到的低激发能级不满足转动谱规律,但当j值足够大时,这些低激发能级满足转动谱规律。The analysis of the quantum phase crossover behavior in the spherical shell model mean-field plus the geometric quadrupole-quadrupole (Q·Q) and standard pairing model within a single-j shell is reported. Several quantities, such as low-lying excitation energies, the overlaps of excited states, ratios of some B(E2) and electric quadrupole moments of some low-lying states as functions of the control parameter of the model in a j=15/2 shell are calculated. The results show that there are noticeable changes in the crossover region of the rotational-like to the pair-excitation phase transition, such as B(E2;41 → 21)/B(E2;21 → 0g) and B(E2;42 → 21)/B(E2;21 → 0g), especially in the half-filling case. Though the low-lying excitation energies generated from the geometric quadrupole-quadrupole interaction not satisfy the pattern of a rotational spectrum when j is small, these energies follow the pattern of a rotational spectrum when j is sufficiently large. 相似文献
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WANGC.Z LIUX XUC.Y WANGL.Y FANGY ZHANGP.X 《光散射学报》2005,17(1):10-12
手二步阳极氧化法制备了大面积上有规则排列纳米洞的阳极氧化铝模板。与一步阳极氧化法的结果进行了比较,SEM测量表明,一步阳极氧化得到的AAO模板正面(对着负电极的一面)和反面,有很大不同,正面纳米洞的分布更不规则,而二步法得到的模板正反面都有排列规则的纳米洞。这一结果也表明阳极氧化过程是一种自组织有序的过程,氧化时间越长,纳米洞的分布越规则越均匀 相似文献
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辐射阻尼和远程偶极场联合作用导致的混沌自旋动态能够产生常见于高场梯度磁共振实验中不可再现的实验结果,且该现象较先前所认为的更为常见.该文发展了一种基于射频微扰的周期性控制方法,以降低Lyapunov指数并抑制在波谱中的不稳定测量结果.同时讨论了周期性控制的设计原则及如何应用在诸多脉冲序列中,用以抑制自旋湍流. 相似文献
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强流质子加速器需要采用分段共振耦合RFQ作为其低能加速结构,为减少束流损失,RFQ加速器必须达到所要求的场分布.针对共振耦合结构的特殊性,在RFQ传输线模型的理论基础上,在一台RFQ冷模型上进行了场调谐的实验研究,获得了满意的实验结果.同时,也验证了作者用LabVIEW编写的RFQ场调谐程序的正确性. 相似文献
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对一长度为3m的分段共振耦合RFQ冷模进行了多次调谐和测量,得到了RF电场平整度好于4%的场分布;解决了分段共振耦合RFQ调谐时耦合单元处RF电场分布出现的台阶问题;确定了分段共振耦合RFQ的调谐步骤. 相似文献
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The RFQ cooler and buncher RFQ1L is a key device of the SHANS (Spectrometer for Heavy Atoms and Nuclear Structure). The status of the machining and assembly of the central part is introduced, and the structure of the whole RFQ1L system and the preliminary plan for the testing are discussed also. 相似文献
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M. Okamura R. A. Jameson H. Kashiwagi T. Hattori N. Hayashizaki K. Sakakibara 《辐射效应与固体损伤》2013,168(10-12):445-449
We have developed a new heavy ion production system which uses a combination of an RFQ and a laser ion source. Induced plasma by a laser shot is delivered to the RFQ without an extraction electrode. We named this new idea ‘direct plasma injection scheme (DPIS)’. In 2004, a new RFQ was built for demonstrating the capability of the DPIS. After a few months of commissioning period, we could obtain more than 60 mA of carbon beam from the RFQ. This new scheme could be applied to cancer therapy facilities and high energy nuclear physics accelerator complexes. 相似文献
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超重核研究谱仪的RFQ冷却聚束器RFQ1L 总被引:2,自引:0,他引:2
介绍了超重核研究谱仪中RFQ冷却聚束器RFQ1L的结构和运用SIMION程序对离子的冷却、聚束、引出和撇气过程的模拟情况。 模拟显示: 通过仔细选择工作点就完全可以把经过充气反冲质量分离器分离后的低品质束流转化为斑点小、发射度小和能量单一的高品质束流, 为紧接其后的磁铁和激光高效率分析提供条件。The structure and the simulation results about the cooling,bunching,extraction and skimming of the RFQ cooler and buncher RFQ1L, which is an important part of the being built super heavy nuclide research spectrometer, have been introduced. It shows that, by careful choice of its working point, we can obtain an ion beam with small beam spot, small emittance and mono energy, which can satisfy the requirements of the successive analyses by dipole and laser with high efficiencies. 相似文献
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Zhou QuanFeng Zhu Kun Guo ZhiYu Kang MingLei Gao ShuLi Lu YuanRong Chen JiaEr 《中国科学:物理学 力学 天文学(英文版)》2011,54(2):271-273
A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.
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中国散裂中子源RFQ的热分析 总被引:1,自引:0,他引:1
射频四级场(RFQ)加速器的水冷具有以下两种功用: 首先它可以把射频场发热带走, 维持RFQ腔的热稳定性及限制RFQ强体形变幅度; 其次, 当RFQ失谐时, 它还可以用来进行RFQ的调谐, 而同时又基本不影响RFQ的射频场分布. 由于RFQ粒子的传输效率对射频场的分布极其敏感, 在RFQ的运行中不再采用传统的用调谐器对RFQ进行调谐的方法. 本文通过热分析, 确定了RFQ加速器的水冷管道的数量和布局及最佳工作水温; 确定了RFQ失谐时, 如何利用水温变化来对RFQ进行调谐的方法. 相似文献
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RFQ冷却聚束器 总被引:1,自引:0,他引:1
简要介绍了RFQ冷却聚束器的基本原理, 并对设计中的RFQ冷却聚束器的特点和利用SIMION程序进行模拟的初步结果进行了讨论.The principle of RFQ (Radiofrequency Quadrupole) cooler and buncher is briefly introduced. The characteristics of the being designed RFQ cooler and buncher and the preliminary results simulated by using the SIMION code are discussed. 相似文献