Terahertz driven dielectric linacs

太赫兹驱动介电直线加速器

• 批准号: ST/N003063/1
• 负责人: Graeme Burt
• 金额: $ 3.43万
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FN003063%2F1
• 关键词: Terahertz; driven; dielectric; linacs

In particle physics, future linear colliders such as CLIC or ILC require ultra-short, sub-picosecond, bunches to obtain the luminosity necessary for the particle physics science exploration. In accelerator based X-Ray sources, sub 10fs bunches are highly sought after, opening new windows on material science. Going beyond these massive accelerators will require higher gradient structures to shrink the size and cost of future high energy colliders. Current metallic microwave structures are limited by electric breakdown to around 100 MV/m.In the drive to obtain every shorter particle bunches, the synchronization of the bunches, both to each other and to facility infrastructure (RF, drive lasers, facility clocks, diagnostic systems) is crucial for the facility optimization, and yet continues to present unsolved problems. Both generation and synchronization of such ultra-short particle beams presents a subsequent problem for the measurement of the ultra-short bunches; only two technologies exist that approach the requirements of future linear colliders and accelerator light sources; laser based 'electro-optic' detection and transverse deflecting cavities. However, EO detection is not currently able to address the few-fs regime, while the gradient requirements make RF (Transverse deflecting cavity) TDC's infeasible for sub-ps measurements on high energy particle physics machines. A high gradient, high frequency (>300 GHz) TDC would allow the same technique to be applied to ultra-short, high energy colliders.Here we propose to develop a blue-skies approach to these problems, using laser generated THz radiation to be coupled to dielectric lined waveguide for acceleration and manipulation of those beams. In extending the GHz-RF techniques into the picosecond/THz regime we gain in time resolution for manipulation and detection; we gain orders of magnitude in the temporal gradient necessary for manipulation on the sub-picosecond time scale; we gain orders of magnitude in energy efficiency, through only generating the accelerating and deflecting fields over a time window matched to the beams to be accelerated (rather than matched to microsecond cavity filling times). Similar high profile research at Stanford has demonstrated gradients in excess of 250 MV/m using laser pulses at much shorter wavelengths. The short timescales involved and the lack of metallic-vacuum transitions prevents the breakdown in the structure up to the dielectric strength of the lining or grating. However in contrast to a wide body of research into optical acceleration methods, the THz approach allows complete trapping of 'conventional' picosecond bunches rather than the high frequency optical smearing associated with the <3fs periods of laser-acceleration concepts. By using THz the electron bunch can occupy a small range of phases producing a far higher quality bunch consistent with requirements from accelerator applications such as colliders and FELs. One of the first steps towards this goal is the demonstration of laser-based schemes for the acceleration and deflection of relativistic electron beams. We propose to take preliminary simulations and experiments to the next stage of proof-of-concept demonstration on STFC's test accelerator, VELA. Our approach is a melding of concepts in electro-optic detection and THz generation (areas of expertise for Jamison and Graham) and particle physics cavity design (expertise of Burt). By using an integrated team the structure and source can be developed in tandem to provide a technology ideally suited to accelerator development. While other experiments have taken place with sub-relativistic particles this would be the first acceleration of fully relativistic particles by a THz structure and would be the first transverse deflecting cavity operating in the THz regime.

在粒子物理学中，未来的线性对撞机（例如 CLIC 或 ILC）需要超短、亚皮秒的束团以获得粒子物理科学探索所需的光度。在基于加速器的 X 射线源中，亚 10fs 束受到高度追捧，为材料科学打开了新的窗口。超越这些大型加速器将需要更高的梯度结构，以缩小未来高能对撞机的尺寸和成本。当前的金属微波结构受到电击穿的限制，约为 100 MV/m。在获得每个较短粒子束的过程中，粒子束之间以及设施基础设施（射频、驱动激光器、设施时钟、诊断）的同步系统）对于设施优化至关重要，但仍然存在未解决的问题。这种超短粒子束的产生和同步都给超短束团的测量带来了后续问题；只有两种技术可以满足未来线性对撞机和加速器光源的要求；基于激光的“电光”检测和横向偏转腔。然而，EO 检测目前无法解决少飞秒范围的问题，而梯度要求使得 RF（横向偏转腔）TDC 无法在高能粒子物理机器上进行亚皮秒测量。高梯度、高频 (>300 GHz) TDC 允许将相同的技术应用于超短、高能对撞机。在这里，我们建议开发一种解决这些问题的蓝天方法，使用激光产生的太赫兹辐射耦合到介电衬里波导以加速和操纵这些光束。在将 GHz-RF 技术扩展到皮秒/太赫兹范围时，我们获得了操纵和检测的时间分辨率；我们获得了在亚皮秒时间尺度上进行操作所需的时间梯度的数量级；通过仅在与要加速的光束匹配的时间窗口内生成加速和偏转场（而不是与微秒腔填充时间匹配），我们获得了几个数量级的能量效率。斯坦福大学类似的引人注目的研究已经证明，使用波长更短的激光脉冲可以产生超过 250 MV/m 的梯度。所涉及的时间尺度短且缺乏金属真空转变可防止结构击穿直至衬里或光栅的介电强度。然而，与光学加速方法的广泛研究相比，太赫兹方法允许完全捕获“传统”皮秒束，而不是与激光加速概念的 <3fs 周期相关的高频光学拖尾。通过使用太赫兹，电子束可以占据小范围的相位，产生质量更高的束，符合对撞机和自由电子激光器等加速器应用的要求。实现这一目标的第一步是演示基于激光的相对论电子束加速和偏转方案。我们建议在 STFC 的测试加速器 VELA 上进行初步模拟和实验，以进行下一阶段的概念验证演示。我们的方法融合了电光探测和太赫兹产生（贾米森和格雷厄姆的专业领域）和粒子物理腔设计（伯特的专业知识）的概念。通过使用集成团队，可以同时开发结构和源，以提供非常适合加速器开发的技术。虽然已经用亚相对论粒子进行了其他实验，但这将是太赫兹结构对完全相对论粒子的首次加速，并且将是在太赫兹范围内运行的第一个横向偏转腔。

项目成果

Characterizing a terahertz-driven dielectric-lined waveguide for electron beam manipulation

表征用于电子束操纵的太赫兹驱动的介电衬里波导

• DOI: 10.1109/irmmw-thz.2018.8509912
• 发表时间: 2018-09-01
• 期刊: 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)
• 作者: V. Georgiadis;A. Healy;M. Hibberd;G. Burt;S. Jamison;D. Graham
• 通讯作者: D. Graham

Electron-terahertz interaction in dielectric-lined waveguide structures for electron manipulation

用于电子操纵的电介质衬里波导结构中的电子-太赫兹相互作用

• DOI: http://dx.10.1016/j.nima.2018.02.025
• 发表时间: 2018
• 期刊: Accelerators, Spectrometers, Detectors and Associated Equipment
• 作者: Healy A

Terahertz-driven acceleration of a relativistic 35 MeV electron beam

太赫兹驱动的相对论 35 MeV 电子束加速

• DOI: http://dx.10.1109/irmmw-thz.2019.8873990
• 发表时间: 2019
• 作者: Hibberd M

Design of a Dielectric-Lined Waveguide for Terahertz-Driven Linear Electron Acceleration at Daresbury

达斯伯里太赫兹驱动线性电子加速的介质衬里波导设计

• 发表时间: 2016
• 作者: Healy A

Group Velocity Matching in Dielectric-Lined Waveguides and its Role in Electron-THz Interaction

介质衬里波导中的群速度匹配及其在电子-太赫兹相互作用中的作用

• DOI: http://dx.10.18429/jacow-ipac2017-wepva019
• 发表时间: 2017
• 作者: Healy Alisa