Intense Beam Dynamics with a the IBEX linear Paul trap

下一代强强子束加速器将用于产生质子、中子和介子束，用于科学和社会应用。由于存在缺陷，即使在线性聚焦系统中，该区域的粒子束动力学本身也是非线性的。这些系统通常没有解析解，在计算机模拟中精确建模极具挑战性。然而，未来的机器和新型加速器概念将需要详细了解空间电荷效应、共振和非线性相互作用之间的相互作用。该项目的主要目的是利用一种新的实验装置对强强子加速器的基本束流动力学有更深入的了解。该项目将专注于加速器中的束流物理，然而，这个项目的影响可能是广泛的，从线性保罗陷阱诊断的潜在新发展，可能应用于其他领域，到可能影响英国和国际上未来主要加速器项目的见解。该学生将使用位于牛津郡STFC卢瑟福阿普尔顿实验室的新型实验设备“强束实验”（IBEX）来研究强束动力学效应。这个实验不是加速器，而是一个叫做线性保罗阱的物理等效系统，在这个系统中，氩离子被限制在实验室框架中，使用射频四极电极。该系统可以近似强粒子束的横向动力学，并且可以应用射频微扰来研究缺陷。该项目将与日本放射研究中心的强光束小组密切合作，并与广岛大学冈本博美教授的光束物理小组进行更广泛的合作。线性（四极）陷阱的初步调查将以广岛大学类似装置的结果为基准，并将包括对整数共振交叉的研究，最初是在低强度制度下，后来是在空间电荷主导制度下。这项初步研究涉及基本的光束动力学主题，特别是与非标度固定场交替梯度加速器相关的主题，其中很少有工作来确定共振交叉现象如何随强光束变化。然后，学生将被期望使用IBEX仪器对其他主题提出自己的研究问题。其中一个方向可能是未来加速器的新晶格结构的稳定性，使用IBEX绘制第一和更高稳定区域的稳定性图，并研究对空间电荷效应的敏感性。另一个可能的方向是建立半整数共振交叉的测试用例，并对ISIS同步加速器的实验进行基准测试。一旦对四极阱的研究正在进行中，学生可以为系统的新诊断的发展做出贡献，以便观察离子等离子体的原位效应，或测量四极或其他模式。该项目与stfc未来设施的战略非常一致，包括在15-20年的时间尺度上研究新的中子散裂源。

The next generation of intense hadron beam accelerators will be used to generate proton, neutron and muon beams for scientific and societal applications. The dynamics of particle beams in this regime is inherently non-linear, even in a linear focusing system, due to the presence of imperfections. These systems usually have no analytical solutions and can be extremely challenging to model accurately in computer simulations. Yet, future machines and novel accelerator concepts will require a detailed understanding of the interplay between space charge effects, resonances and non-linear interactions. The primary aim of this project is to establish a greater understanding of fundamental beam dynamics of intense hadron accelerators using a new experimental apparatus. The project will focus on the physics of beams in accelerators, however the impact of this project may be wide-ranging from potential new developments of diagnostics for linear Paul traps which may be applied in other fields to insights which could impact on major future accelerator projects in the UK and internationally. The student will investigate intense beam dynamics effects using a new experimental apparatus, the 'Intense Beam Experiment' (IBEX) located at the STFC Rutherford Appleton Laboratory in Oxfordshire. This experiment is not an accelerator, but a physically equivalent system called a linear Paul trap, where Argon ions are confined in the lab frame using rf quadrupole electrodes. This system can approximate the transverse dynamics of intense particle beams and rf perturbations can be applied to study imperfections. The project will be carried out in close collaboration with the Intense Beams Group at RAL and in wider collaboration with Prof. Hiromi Okamoto's beam physics group at University of Hiroshima. Initial investigations with the linear (quadrupole) trap will be benchmarked against results from a similar setup at Univ. Hiroshima and will include studies of integer resonance crossing initially in the low intensity regime and later in a space charge dominated regime. This initial research pertains to fundamental beam dynamics topics particularly relevant to non-scaling fixed field alternating gradient accelerators, where little work has been done to establish how the phenomenon of resonance crossing changes with intense beams. The student will then be expected to contribute to developing their own research questions on other topics using the IBEX apparatus. One such direction may be the stability of novel lattice configurations for future accelerators, using IBEX to map out stability diagrams in the first and higher stability regions and investigating sensitivity to space charge effects. Another possible direction is to establish a test case for half integer resonance crossing and benchmark against experiments on the ISIS synchrotron. Once investigations with the quadrupole trap are underway, the student may contribute to the development of novel diagnostics for the system in order to observe effects of the ion plasma in-situ, or to measure quadrupole or other modes.This project is well aligned with STFCs strategy for future facilities, including the investigation of a new neutron spallation source on a 15-20 year timescale.