Intense Beam Dynamics with a the IBEX linear Paul trap

下一代强流强子束加速器将用于产生用于科学和社会应用的质子、中子和µ子束。由于缺陷的存在，即使在线性聚焦系统中，粒子束在这个区域的动力学本质上也是非线性的。这些系统通常没有解析解，并且在计算机模拟中精确建模可能是极具挑战性的。然而，未来的机器和新的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。这个项目的主要目的是利用一种新的实验设备来更好地理解强子加速器的基本束动力学。该项目将专注于加速器中的束流物理，然而，该项目的影响可能是广泛的，从可能应用于其他领域的线性Paul陷阱诊断的潜在新发展，到可能对英国和国际未来重大加速器项目产生影响的见解。这名学生将使用一种新的实验设备--位于牛津郡卢瑟福·阿普尔顿实验室的强流束实验(IBEX)--来研究强流束动力学效应。这个实验不是加速器，而是一个被称为线性保罗陷阱的物理等效系统，在这个系统中，使用射频四极电极将Ar离子限制在实验室框架内。该系统可以近似强流粒子束的横向动力学，射频微扰可以用来研究缺陷。该项目将与RAR的强束小组密切合作，并与广岛大学冈本广美教授的束物理小组进行更广泛的合作。对线性(四极)陷阱的初步调查将以大学类似设置的结果为基准。广岛和将包括最初在低强度区域和后来在空间电荷主导区域的整数共振交叉的研究。这项初步研究涉及基本束流动力学主题，特别是与无标度固定场交变梯度加速器有关的主题，其中几乎没有工作来确定共振交叉现象如何随着强流束流的变化而变化。然后，学生将被期望使用IBEX设备来开发他们自己的关于其他主题的研究问题。一个这样的方向可能是未来加速器的新晶格构型的稳定性，使用IBEX绘制第一个和更高稳定性区域的稳定性图，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，并以ISIS同步加速器上的实验为基准。一旦四极陷阱的研究正在进行中，学生可能会为开发新的系统诊断方法做出贡献，以便在现场观察离子等离子体的影响，或测量四极或其他模式。该项目与STFCS未来设施的战略很好地结合在一起，包括在15-20年的时间尺度上调查新的中子散裂源。

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.