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对一种工业用大功率电子加速器(450kW)的加速管中的空间电荷效应作了5点假设,建立了物理模型。对模型的束内外径向电位分布、空间电荷对轴上电位的影响,以及空间电荷力对束流传输的影响等进行了理论分析,得到了束内径向电位分布。结果表明:束流内部径向电位沿径向均呈抛物线变化,并在轴上达到最小值;而空间电荷产生的束内电场与半径呈线性变化;空间电荷不仅会引起轴上电位的跌落,而且对束流有发散作用,特别是在电子速度较低时更为明显。在考虑了空间电荷效应后,强流静电加速管的电场设计关键在加速管的前端,与弱流加速管相比,强流加速管的电场变化要大得多。 相似文献
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基于KONUS束流动力学理论,完成了一台工作频率为162.5 MHz、占空比为1%的交叉指型漂移管直线注入器(IH-DTL)的动力学设计。该IH-DTL内置两套三组合四极透镜,共有41个加速单元,可为同步加速器提供流强400 eμA、能量4 MeV/u的C4+束流。在动力学设计过程中着重对每个加速间隙的同步能量偏差、注入相位和间隙电压等参数进行优化,使得该IH-DTL的横向归一化RMS接收度达到0.24 πmm·mrad,且横纵向归一化发射度增长小于10%,有利于提高同步环的注入效率。然后根据动力学设计的结构参数进行IH-DTL的高频仿真计算,将得到的三维电磁场分布导入PIC粒子跟踪程序中进行束流动力学模拟。动力学模拟结果显示,束流在IH-DTL出口的横向自然发射度小于13 πmm·mrad,达到了同步环的注入要求,而且在7%的垂直二极场分量下,束流中心的横向偏移在±0.5 mm以内,整体的束流传输效率高于99%。An interdigital H-mode drift tube linac (IH-DTL) with KONUS beam dynamic has been designed, which operation frequency was chosen 162.5 MHz. This IH-DTL consists of 41 accelerating cells and two quadrupole magnets triplets, can provide the C4+ with the current of 400 eμA and energy of 4 MeV/u for the synchrotron. In the beam dynamic design, the synchronous particle energy, inject RF phase and the acceleration voltage of each gap are optimized carefully to make the transverse normalized RMS acceptance of the IH-DTL to be 0.24 πmm·mrad and the beam emittance growth small than 10%. Then the RF structure was designed and the 3D electromagnetic field was imported into the PIC particle tracking code for the beam dynamic simulation. The transverse beam emittance at the exit of the IH-DTL is small than 13πmm·mrad which meets the injection requirement of the synchrotron. What is more, under the 7% vertical dipole fields component, the offset between the beam center and the drift tube's axis is ±0.5 mm at most. The transmission efficiency of the IH-DTL is higher than 99% for the whole beam in the acceptance. 相似文献
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The superconducting spoke cavity has been proposed to accelerate the proton in the low energy section of high power proton linac for an Accelerator Driven Sub-critical System (ADS). Considering that the High Order Modes (HOMs) in the superconducting cavity have far reaching influence on power dissipation and beam stability, the analysis of HOMs of the spoke cavity is needed. In this paper, we put emphasis on the analysis of HOMs of the spoke cavity and the HOMs coupler design. 相似文献
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In the RD of the CSNS Drift Tube Linac(DTL),the first unit tank with 28 drift tubes has been developed.The axial accelerating field is ramped from 2.2 MV/m to 3.1 MV/m in this tank.The required field flatness is less than±2%with the standard deviation of 1%for the beam dynamics;the field stability should be less than 1%for machine stable operation.After successful alignment,RF tuning was carried out focusing on the field profile measurement.Four slug tuners and eleven post couplers were applied in this procedure.The ramped field and required stability had been achieved by fine adjustment of the slug tuners and post couplers.In this paper,the preliminary tuning results are presented and discussed. 相似文献
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现代智能优化算法粒子群算法\,(Particle Swarm Optimization)\,在加速器设计优化上的应用逐渐增多。交变相位聚焦直线加速器\,(Alternative Phase Focused Drift Tube Linac)\,具有节省空间和造价的优点。将交变相位聚焦直线加速器的初步设计方案作为种子,植入粒子群算法中;以加速器的传输效率和束流能量作为目标,得到该方案的Pareto最优解集;在粒子进化过程中,以前沿解集作为粒子的运动方向,以前沿解集的束流径迹作为粒子的参数来源。最终得到了满足能量增益的高传输效率、大接受度的优化方案。The Particle Swarm Optimization(PSO), one of the modern intelligent optimization algorithms,is increasingly employed in the design and optimization of accelerators. Alternative Phase Focused Drift Tube Linac(APF DTL) has an advantage in cost-effecient fabrication and reduced construction space. The preliminary design of APF DTL is involved in the optimization as the anchor; by taking the acceleration efficiency and the beam energy as two fitness functions, the Pareto optimal set is obtained; the evolutionary direction is determined by the Pareto optimal set and the particles’ parameters in the optimization are derived from the simulations of the randomly selected Pareto optimal solutions. A final optimized design with extracted energy of 5.35 MeV/uand acceleration efficiency greater than 83% is acquired. 相似文献
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乔舰 殷学军 原有进 杨建成 冒立军 殷达钰 张小虎 杜衡 李小妮 李钟汕 吴波 赵贺 汤梅堂 秦元帅 石健 盛丽娜 柴伟平 申国栋 阮爽 王耿 刘杰 秦志明 王科栋 董自强 蔡付成 陈孝强 孔启宇 《原子核物理评论》2017,34(2):170-176
为了提高兰州重离子加速器冷却储存环(HIRFL-CSR)的运行效率、改善加速器输出束流品质,并实现几个加速装置分时供束,提高整个重离子加速装置的利用率,特为(HIRFL-CSR)增建一台新的注入器--CSRLINAC。在108.48 MHz的RFQ之后的CSR-LINAC主加速段,主要由一台108.48 MHz和两台216.96 MHz的IH型漂移管直线加速器组成,用于加速荷质比为1/8.5~1/3之间的重离子,其最大的束流流强为3 mA,并将粒子从0.3 MeV/u加速到3.71 MeV/u。运用KONUS动力学原理,在满足设计指标的情况下,首先利用TraceWin程序进行中能束线MEBT设计,后针对高频腔体设计和束流匹配的基本参数的系列讨论,特别是对CSR-LINAC的中能束流匹配线、参数选择和IH型KONUS结构的漂移管直线加速器进行设计模拟优化。最终得出,在保证腔体设计指标和95.3%的传输效率的情况下,该紧凑型直线加速结构经过三个腔体的加速后,束流的纵向归一化均方根发射度增长仅有25%;同时发现,当流强达到3 mA时,存在空间电荷效应,导致其纵向相宽增长约25%,最大横向包络也存在16.5%的涨落。In order to improve the operation efficiency of the Cooling Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR), a heavy ion linac (linear accelerator) was proposed and designed as a new injector for HIRFL-CSR. Following the 108.48 MHz Radio-Frequency Quadrupole (RFQ), three tanks in total with Interdigital H-mode drift tube linac (IH-DTL) structure are installed to boost the beam energy from 0.3 to 3.71 MeV/u, and the beam current of ions with charge-to-mass ratio from 1/8.5 to 1/3 can reach to 3 mA. The first tank operatesat the same frequency as the RFQ, and the rest two operate at 216.96 MHz. The “Combined Zero-Degree Synchronous Particle Structure” (KONUS) beam dynamics was used in the beam dynamics design. The overview of the physics design on the main accelerating components, including RF design and beam dynamics design are introduced in this paper. The optimized structure design, fabrication status and simulation results are presented in this contribution. It shows that under the condition of assurance of 95.3% transmission efficiency, the normalized rms emittance is about 25%. When the beam current is up to 3 mA, owing to the space charge effect, the increase of longitudinal phase spread and transverse envelope are about 25% and 16.3%, respectively. 相似文献