IH-DTL直线加速器的设计及实验研究

发布时间：2018-11-25 15:18

【摘要】：兰州重离子研究装置(HIRFL)目前由SFC(扇聚焦回旋加速器)、SSC(分离扇回旋加速器)、CSRm(冷却储存环主加速器)和CSRe(冷却储存环实验平台)构成,其中SFC作为唯一的注入器不能同时保证SSC与CSRm的供束。为了提高整个HIRFL的运行效率,近代物理研究所为SSC专门设计了一台CW运行的重离子直线注入器,能够为SSC提供能量为0.58MeV/u或者1.025MeV/u,质荷比为3-7的强流连续的重离子束。它由一台ECR离子源、一台RFQ和四台IH-DTL构成。本论文从动力学优化设计出发,依次对SSC直线注入器IH-DTL1的高频仿真设计、高频腔体测量、功率耦合器设计、高功率锻炼和束流调试进行讨论分析,同时束流动力学相关的PIC粒子跟踪模拟贯穿整个论文。对IH-DTL1腔体测量以及功率锻炼过程中发现的问题做出了分析并解决,且在IH-DTL2的设计中进行了针对性的优化。通过SSC直线注入器RFQ及IH-DTL1的束流实验,验证了其动力学设计的有效性。通过对SSC直线注入器IH-DTL1的动力学模拟分析,发现了其在保证束流品质的前提下引出能量在一定范围内连续可调的特性,并通过初步的束流实验进行了验证。另外通过对IH-DTL3、4进行束流动力学研究提出来将其合并成一个加速腔改进方案,使整个SSC直线注入器更加紧凑。基于在SSC直线注入器设计和调试的经验,近代物理研究所为医用重离子装置HIMM提出了注入器的升级改造项目即采用紧凑型直线注入器代替原来的回旋加速器。采用直线注入器能够大提高同步环注入束的流强及束流品质。本论文针对HIMM直线注入器的束流要求进行了主加速段DTL的动力学设计,采用了KONUS束流动力学方案使得加速梯度非常高,从而整个DTL可由一个独立的IH型加速腔实现。通过对加速结构的优化,将该DTL中束流发射度增长限制在10%,并且有足够强的误差容忍性。根据动力学设计的结果进行了腔体高频设计,着重对IH-DTL的电场分布、调谐器调谐能力及耦合器的优化选择进行分析讨论,最终确定了腔体的结构。最后基于高频设计得到的腔体电场分布对HIMM直线注入器DTL段进行全面的束流动力学模拟计算,增加了设计的可靠性。通过上述SSC直线注入器和HIMM直线注入器的设计研究,为近物所常温直线加速器的设计和运行积累了丰富的经验。
[Abstract]:At present, the Lanzhou heavy Ion Research Facility (HIRFL) is composed of SFC (Fan focusing Cyclotron,), SSC (separated Fan Cyclotron,), CSRm (cooling Storage Ring main Accelerator) and CSRe (cooling Storage Ring Experimental platform). SFC as the only injector can not guarantee the supply of SSC and CSRm at the same time. In order to improve the efficiency of the whole HIRFL, the Institute of Modern Physics specially designed a CW running heavy ion linear injector for SSC, which can provide the SSC with energy of 0.58MeV/u or 1.025 MeV / u. A continuous heavy ion beam with a mass charge ratio of 3 to 7. It consists of one ECR ion source, one RFQ and four IH-DTL. Starting from the dynamic optimization design, this paper discusses and analyzes the high-frequency simulation design of SSC linear injector IH-DTL1, the measurement of high-frequency cavity, the design of power coupler, the high-power training and beam debugging. At the same time, the PIC particle tracking simulation related to beam dynamics runs through the whole thesis. The problems found in the measurement of IH-DTL1 cavity and power training are analyzed and solved, and the design of IH-DTL2 is optimized. The effectiveness of the dynamic design is verified by the beam experiments of SSC linear injector RFQ and IH-DTL1. Through the dynamic simulation analysis of SSC linear injector IH-DTL1, it is found that the energy can be continuously adjustable in a certain range under the premise of ensuring the beam quality, and it is verified by a preliminary beam experiment. In addition, the beam dynamics of IH-DTL3,4 is studied to combine it into an improved scheme of accelerating cavity, which makes the whole SSC linear injector more compact. Based on the experience of designing and debugging the linear injector in SSC, the Institute of Modern Physics has proposed an upgrade project of the injector for the medical heavy ion device HIMM, that is, the compact linear injector is used instead of the original cyclotron. The linear injector can greatly improve the current intensity and beam quality of the synchronous ring injection beam. In this paper, the DTL dynamic design of the main acceleration section is carried out according to the beam requirement of the HIMM linear injector. The KONUS beam dynamics scheme is adopted to make the acceleration gradient very high, so that the whole DTL can be realized by an independent IH cavity. By optimizing the accelerating structure, the beam emittance increase in the DTL is limited to 10%, and the error tolerance is strong enough. According to the results of dynamic design, the cavity high frequency design is carried out. The electric field distribution of IH-DTL, tuner tuning ability and the optimum selection of coupler are analyzed and discussed. Finally, the structure of cavity is determined. Finally, the beam dynamics of the DTL segment of the HIMM linear injector is simulated based on the electric field distribution of the cavity obtained by the high-frequency design, which increases the reliability of the design. Through the design and research of the SSC linear injector and the HIMM linear injector, rich experience has been accumulated for the design and operation of the near-object normal temperature linear accelerator.
【学位授予单位】：中国科学院大学(中国科学院近代物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TL53

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