High-Speed, High-Resolution Diagnostic System for a Plasma Wakefield Accelerator

该项目旨在开发一种新的诊断方法，用于测量先进粒子加速器概念（即所谓的等离子体韦克菲尔德加速器（PWFA））的物理过程。PWFA研究的最终目标是将未来粒子加速器的占地面积，能耗和成本降低几个数量级，用于从X射线自由电子激光器到高能粒子对撞机的应用。 目前，还没有合适的诊断加速器等离子体源已经开发，该问题的研究领域的瓶颈。等离子体源的特性必须是非侵入性的，并且精确到百分之几的水平，以避免破坏加速电子束的质量。这就需要部署能够探测宏观和瞬态等离子体源的诊断技术，其分辨率为1000或更高，这超出了传统等离子体诊断系统的应用范围。本项目将为开发一种先进的综合诊断技术系统奠定基础，该系统旨在非侵入性地解析等离子体源密度分布（典型密度范围：每立方厘米10^15到10^18），空间分辨率为~mm，时间分辨率为~ps。各个诊断子系统将基于已知和经过验证的技术，这些技术相互配合运行，以显著减少整个系统的系统误差。三个主要的诊断子系统分别依赖于斯塔克加宽、汤姆逊散射和光发射（“等离子体辉光”）的原理。该项目的目标是：1）为每个诊断系统建立详细的模型和预期信号的模拟，2）使用小的、表征良好的测试等离子体源单独测试和优化每个系统，3）集成所有系统并执行测试等离子体源的同时测量，以及4）开发分析框架，该分析框架组合由所有诊断系统收集的数据并且使恢复的等离子体密度分布中的系统误差最小化。该项目的成功将为未来的项目指明方向，该项目将采用成像光谱仪提供单次拍摄，空间分辨等离子体丝密度分布。这将与超短激光探测脉冲和快速选通CCD相机的使用相结合，以提供最佳的时间分辨率和信噪比。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project is aimed towards development of a new diagnostic that will measure the physical processes underlying an advanced particle accelerator concept, a so-called plasma wakefield accelerator (PWFA). PWFA research has the ultimate goal of reducing the footprint, energy consumption, and cost of future particle accelerators by several orders of magnitude for applications ranging from X-ray free electron lasers to high-energy particle colliders. Currently, no suitable diagnostics for the accelerator plasma source have been developed, and the problem approaches a research bottleneck for the field. The characterization of the plasma source must be non-intrusive and accurate to the few-percent level in order to avoid spoiling the quality of the accelerated electron beam. This necessitates the deployment of diagnostics capable of probing a macroscopic and transient plasma source with percent-level resolution, or better, which lies outside of the application of conventional plasma diagnostic systems.This project will lay the groundwork for the development of an advanced, integrated system of diagnostic techniques intended to non-intrusively resolve the plasma source density profile (typical density range: 10^15 to 10^18 per cm^3) at the percent level in a single shot, with a spatial resolution of ~mm and a temporal resolution of ~ps. The individual diagnostic sub-systems will be based upon known and proven techniques that are run in tandem with one another to significantly reduce the systematic errors of the full system. The three primary diagnostic sub-systems rely on the principles of Stark broadening, Thomson scattering, and optical emission ("plasma glow"), respectively. The goals of the project are 1) to build detailed models and simulations of the expected signals for each of the diagnostic systems, 2) to test and optimize each system individually using a small, well characterized test plasma source, 3) to integrate all systems and perform simultaneous measurements of the test plasma source, and 4) to develop the analysis framework that combines the data collected by all of the diagnostic systems and minimizes the systematic errors in the recovered plasma density profile. The success of this project will point the way forward for an intended future project that incorporates an imaging spectrometer to provide a single-shot, spatially resolved plasma filament density profile. This will be combined with the use of an ultra-short laser probe pulse, and a fast-gated CCD camera to provide the best possible temporal resolution and signal-to-noise ratio.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.