CAREER: Computing Radiation Spectra in Compton Sources with High Precision

X射线使科学家能够研究从宏观到单个原子位置的所有长度尺度上的材料内部结构。这种能力对科学、技术和世界经济产生了深远的影响。科学界一致认为，许多科学和技术领域的未来进步取决于对纳米尺度上结构-功能关系的理解，在纳米尺度上，新的性质会出现。控制复杂材料的制造规模将允许新的物理，化学和生物功能。康普顿辐射源的输出通量和亮度可以与现代同步辐射源相媲美，甚至在某些方面超过了现代同步辐射源，将最先进的科学和医学X射线探针带入了大学、工业和医学实验室。在这方面，该项目将改进康普顿源辐射谱的计算。如果成功，这种新方法有望在开创硬X射线源技术的新时代方面发挥关键作用。结合强大的优化工具，这将导致所有现有和未来康普顿源的性能大幅改善。当相对论电子束与激光束相互作用时，通过康普顿散射产生强烈且高度准直的电磁辐射。增加激光强度会改变电子碰撞过程中的纵向速度，这会导致散射辐射谱的显著加宽。这种有质动力展宽的影响是如此有害，以至于大多数康普顿光源要么保持在低激光强度，要么付出高昂的代价，以物理上可能的峰值光谱输出的一小部分工作。在这个项目中，PI和他的合作者将建立在以前的工作基础上，这些工作表明单个电子的有质动力加宽可以通过入射激光波的适当频率调制（啁啾）来消除。PI将把这种啁啾处方推广到现实的电子束和激光脉冲，以量化其优点。具有啁啾声的康普顿源的高保真模拟预计将大幅节省现有康普顿源的运营成本以及新康普顿源的设计和建造成本。该奖项反映了NSF的法定使命，并且通过使用该基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

X-rays enable scientists to study the internal structure of materials on all length scales from the macroscopic down to the positions of individual atoms. This capability has had profound impact on science, technology, and on the world economy. The community is in agreement that future advances in many areas of science and technology depend on understanding the structure-function relationships at the nano-scale, where new properties emerge. Controlling the fabrication of complex materials at that scale will allow for novel physical, chemical, and biological functionality. Output flux and brilliance of Compton sources rivals, and by some measures exceeds, modern synchrotron sources, bringing the most advanced scientific and medical X-ray probe into the university, industrial, and medical laboratory. In this context, this project will improve the calculation of radiation spectra in Compton sources. If successful, the new approach is expected to play a pivotal role in ushering a new era in hard X-ray source technology. Combined with powerful optimization tools, this will lead to substantial improvements in performance for all existing and future Compton sources.When a relativistic electron beam interacts with a laser beam, intense and highly collimated electromagnetic radiation is generated through Compton scattering. Increasing the laser intensity changes the longitudinal velocity of the electrons during their collision, which leads to considerable broadening in the scattered radiation spectra. The effects of such ponderomotive broadening are so deleterious that most Compton sources either remain at low laser intensities or pay a steep price to operate at a small fraction of the physically possible peak spectral output. In this project, the PI and his collaborators will build on previous work that showed that the ponderomotive broadening for individual electrons can be eliminated by suitable frequency modulation (chirping) of the incident laser wave. The PI will generalize this chirping prescription to realistic electron beams and laser pulses, in order to quantify its advantages. High-fidelity simulations of Compton sources with chirping are expected to lead to substantial savings in the operational costs of the existing as well as the design and construction cost of new Compton sources.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.