Ultra-Low Emittance Electron Beams from Laser-Plasma Photo-Cathodes

物理、生物医学、材料科学和化学等基础研究的进展，关键取决于高能电子的质量。电子目前的一个重要应用是X射线放射学，用于医疗诊断、国土安全、无损分析和计算机制造。通过开发用激光加速电子的新方法，该项目旨在展示大幅提高电子束质量的新技术。在这一过程中，新一代的科学、技术、工程和数学学生将接受被认为对国家科学和经济竞争力至关重要的学科的培训。近年来，紧凑型高场梯度激光等离子体加速器发展迅速。最近的几项理论研究预测了超低发射度光束的可能性(大大低于目前的技术水平)。然而，这些预测还有待实验验证。这类实验将在该项目期间使用尖端激光技术进行，包括内布拉斯加州大学极端光实验室提供的PB级峰值功率级迪奥克勒斯激光器。激光将被用来注入和加速电子，产生创纪录的低发射率光束。将开发和实施新的方法来测量超低束发射度。实验结果将与建模和模拟的预测进行比较，以验证现有的物理模型，或开发与观测相一致的新模型。预计这项研究将大大提高我们对激光尾波场电子加速器基本物理的理解，并进一步推动其发展。

The progress of basic research into physics, biomedicine, materials science, and chemistry depends critically on the qualities of high-energy electrons. An important current application of electrons is x-ray radiology, used for medical diagnostics, homeland security, non-destructive analysis, and computer manufacturing. By developing novel methods to accelerate electrons with laser light, this project aims to demonstrate new techniques to greatly improve the quality of electron beams. In the process, a new generation of students in science, technology, engineering, and mathematics will receive training in disciplines deemed essential for national scientific and economic competitiveness. The development of compact high-field-gradient laser-plasma accelerators has advanced rapidly in recent years. Several recent theoretical studies predict the possibility of ultra-low emittance beams (substantially lower than the current state of the art). However, these predictions have yet to be tested experimentally. Such experiments will be conducted during this project with the cutting-edge laser technology, including the petawatt peak-power-level DIOCLES laser, available at the University of Nebraska's Extreme Light laboratory. Laser light will be used to both inject and accelerate electrons, producing beams with record low emittance. Novel methods will be developed and implemented to measure ultra-low beam emittance. The experimental results will be compared with predictions of modeling and simulation?to either validate existing physical models, or develop new ones that agree with observations. It is anticipated that this research will significantly improve our understanding of the fundamental physics of laser-wakefield electron accelerators, as well as further advance their development.