Femtosecond-micrometer spatiotemporal alignment of particle and laser beams

粒子束和激光束的飞秒微米时空对准

• 批准号: 2123491
• 金额: --
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2123491
• 关键词: Femtosecond; micrometer; spatiotemporal; alignment; particle

Alastair Nutter will be developing a novel versatile method for spatiotemporal alignment and synchronization of particle and laser beams. The underlying principle was discovered as a key result of a multi-year experimental campaign obtained by the E210 collaboration at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory at Stanford, one of our strategic partners. The project will be done co-funded by our partner at Helmholtz-Institute Dresden-Rossendorf (HZDR) in Germany. HZDR did not only agree to co-fund this PhD project directly, but will also be providing substantial resources into the burgeoning collaboration in terms of using beamtime at their PW-class laser system to the tune of ~10 weeks per year, and may be additionally investing into significant SCAPA beamtime (daily fees for the 350 TW laser at SCAPA are £ 3300). The student will be based at Strathclyde, but will also be placed at HZDR for extended times, in line with the international aspect of the Strathclyde CDT on Plasma-based Particle and Light Sources http://ppals.phys.strath.ac.uk/ . The coordinated interaction of intense laser and electron beams plays an ever-increasing role, for example for various pump-probe experiments and imaging of the ultrafast and ultrasmall. This requires precise techniques to measure and control temporal and spatial overlap of the interaction. We have discovered a fundamental effect which permits plasma-photonic synchronization and alignment of intense laser and electron beams with femtosecond and micrometer precision in a single robust apparatus. A laser-generated cold plasma filament picks up the electric field of a transient electron beam to varying degree, seed plasma electrons are heated by this coupling and perform complex oscillations which extend into ambient gas. Here, their non-relativistic energies are just right to generate substantial amount of additional plasma via impact ionization. This acts as a 'magnifying glass', transforming the specific femtosecond-micrometer interaction signature into visible plasma recombination / de-excitation light, which is observable on microsecond-millimeter scales.We have already exploited this basic effect to demonstrate combined spatiotemporal synchronization and alignment of the SLAC Stanford 20 GeV electron beam with a focused Ti:Sapphire laser with femtosecond-micrometer accuracy. This approach enables advanced diagnostics which will improve a wide range of pump-probe experiments substantially, and allows to realise advanced spatiotemporally resolved experiments which are hitherto not feasible. The phenomena also shed light on the previously hidden importance of impact ionization for instance in advanced plasma accelerator experiments. Supporting particle-in-cell simulations reveal fascinating dynamics over a wide range of time and length scales: The initial fs-scale kick by the electron beam is spread along the thin seed filament by plasma density waves and corresponding GV/m scale fields on the ps-scale, and impact ionization and recombination processes then take place on the ns-us time scale.In Stanford, we have been using a basic version of this effect, using an electron beam generated in a conventional linear accelerator. Alastair's PhD work will develop this method of spatiotemporal alignment further, such that it will be available in advanced shape when FACET-II, the follow-up plasma wakefield accelerator facility in Stanford will come online in 2019 for user-assisted commissioning. However, the effect has even wider applicability and can be used to enable advanced plasma wakefield acceleration at laser-plasma accelerator facilities such as SCAPA or HZDR. For this, the electron beam is generated not by a conventional accelerator, but by a laser-plasma-accelerator.

Alastair Nutter将开发一种新型的多功能方法，用于粒子和激光束的空间时间对齐和同步。基本原则是作为我们战略合作伙伴之一的斯坦福大学SLAC国家加速器实验室的高级加速器实验测试设施（FACET）的E210合作进行了多年实验运动的关键结果。该项目将由我们在德国的Helmholtz-Institute Dresden-Rossendorf（HZDR）的合伙人共同资助。 HZDR不仅同意直接共同获得该博士学位项目，而且还将为新兴的合作提供大量资源，以在其PW级激光器系统中使用Beamtime每年10周的调音，并且还可以额外投资于Scapa Beam Time（Scapa 350 Tw Laser的每日费用）。该学生将位于Strathclyde，但也将与基于等离子体的粒子和光源的Strathclyde CDT的国际方面http://ppals.phys.phys.strath.ac.ac.uk/相符。强烈激光和电子束的协调相互作用起着不断增长的作用，例如用于各种泵探针实验以及超快和超毛的成像。这需要精确的技术来测量和控制相互作用的临时和空间重叠。我们发现了一种基本效果，该效应允许血浆 - 光子同步以及激光和电子束在单个鲁棒设备中使用飞秒和微米精度的对齐。激光生成的冷等离子体丝将瞬态电子束的电场拾起到不同程度的电场，通过这种耦合，种子等离子体电子被加热并进行复杂的振荡，以扩展到环境气体。在这里，他们的非权利主义能量是通过撞击电离产生大量额外等离子体的合适性。这起作用是“放大玻璃”，将特定的飞秒微微度计的相互作用转换为可见的等离子体重组 /去激光的光，在微秒毫秒毫米尺度上可以观察到，我们已经探索了这种基本效果。飞秒微米计的精度。这种方法可以实现高级诊断，这将大大改善广泛的泵送实验，并允许实现迄今不可行的高级空间解决实验。该现象还阐明了撞击电离的先前隐藏的重要性，例如在高级等离子体加速器实验中。支撑粒子中的颗粒模拟揭示了在各种时间和长度尺度上的引人入胜的动力学：电子束的初始FS尺度通过血浆密度波和相应的GV/M尺度场沿薄的种子灯丝沿薄的种子灯丝散布，然后在ns-us time stare.ins time a ins the Electron上，在PS量表上进行了效果。传统的线性加速器。阿拉斯泰尔（Alastair）的博士学位工作将进一步开发这种时空对齐方式，以便在Facet-II（Stanford的后续等离子Wakefield Accelerator设施）将于2019年在网上进行用户辅助调试时，它将以先进的形式获得。但是，这种效果甚至更广泛，可用于在激光 - 血浆加速器设施（例如SCAPA或HZDR）上启用高级等离子体Wakefield加速。为此，电子束不是由常规加速器而是由激光 - 铂 - 加速器生成的。