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，它将测量先进的粒子加速器概念背后的物理过程，即所谓的等离子体尾迹加速器(PWFA)。PWFA研究的最终目标是将未来粒子加速器的占地面积、能源消耗和成本降低几个数量级，适用于从X射线自由电子激光到高能粒子对撞机的各种应用。目前，还没有针对加速器等离子体源的合适的诊断方法，这一问题成为该领域的研究瓶颈。为了避免破坏加速电子束的质量，等离子体源的特性必须是非侵入性的，并且精确到几个百分点的水平。这就需要在常规等离子体诊断系统的应用之外，部署能够探测具有百分级或更高分辨率的宏观和瞬变等离子体源的诊断学。该项目将为开发先进的、集成的诊断技术系统奠定基础，该系统旨在非侵入性地在单次发射中分辨出等离子体源密度分布(典型密度范围：10^15到10^18/cm^3)，空间分辨率为~mm，时间分辨率为~ps。单独的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。这三个主要的诊断子系统分别依靠斯塔克展宽、汤姆森散射和光学发射(“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预期信号的详细模型和仿真，2)使用一个小的、特性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，将所有诊断系统收集的数据结合在一起，并将恢复的等离子体密度分布中的系统误差降至最低。该项目的成功将为未来的一个预期项目指明前进的方向，该项目将结合成像光谱仪，提供单次发射、空间分辨的等离子体细丝密度分布。这将与使用超短激光探测脉冲和快速选通的CCD相机相结合，以提供尽可能最佳的时间分辨率和信噪比。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势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.