MRI: Development of a Multiuser Instrument for Attosecond X-Ray Probing of Correlated Quantum Dynamics

自1895年被发现以来，x射线在医疗技术以及材料和蛋白质的元素和结构分析中得到了许多应用。随着新的激光技术的出现，产生持续时间小于万亿分之一秒（一阿秒）的百万分之一的x射线爆发已经成为可能。这些新型的超短x射线脉冲可以为研究与光收集和催化有关的复杂分子的内部工作提供一个窗口，并指导量子信息处理新材料的开发。该项目的研究人员将通过开发一种仪器平台来创造新的x射线研究机会，该平台将x射线脉冲与最先进的探测器（如瞬态x射线光谱仪和电子成像）集成在一起。这项工作的目标将是直接观察、操纵和实时控制分子和材料中的量子过程，这对我们国家的能源、信息和安全利益至关重要。因此，该项目将增强美国的科学竞争力，并培训新x射线技术的下一代劳动力。具体而言，该项目旨在开发一种时间分辨多功能阿秒x射线光谱台式仪器，该仪器将实现终极时间分辨率，以化学灵敏度，原子分辨率和轨道选择性来探测分子和材料中的电荷再分配动力学。该仪器将覆盖软x射线范围从100到1000电子伏特使用高功率中红外激光谐波产生。阿秒分辨率、高通量和元素特异性的结合将把x射线光谱能力扩展到一个新的领域，从而形成一个独特的多用户仪器，对基本电子过程，特别是涉及相关电子动力学的过程有新的见解。该仪器将为学生和早期职业研究人员提供方便的访问和研究培训机会。该开发项目集成了瞬态x射线吸收光谱、光电子光谱、条纹能力和同步电荷粒子成像，以服务于亚利桑那大学的广泛用户群，以及国家层面的其他科学家。该奖项反映了美国国家科学基金会的法定使命，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。

Since their discovery in 1895, x-rays have found numerous applications in medical technologies and in the elemental and structural analysis of materials and proteins. With the advent of new laser technologies, it has become possible to produce x-ray bursts of duration less than a millionth of a trillionth of a second (an attosecond). These novel ultrashort x-rays pulses can provide a window into the inner workings of complex molecules relevant to light harvesting and catalysis and guide the development of novel materials for quantum information processing. Researchers working on this project will create new x-ray research opportunities by developing an instrumental platform that integrates the x-ray pulses with state-of-the-art detectors, such as transient x-ray spectrometer and electron imaging. The goal of this effort will be direct observation, manipulation, and real-time control of quantum processes in molecules and materials, the pursuit of which is vital to energy, information, and security interests of our nation. The project will thus enhance US scientific competitiveness and train the next generation workforce in new x-ray technologies.Specifically, the project aims to develop a tabletop instrument for time-resolved multifunctional attosecond x-ray spectroscopy, which will realize the ultimate time-resolution to probe the dynamics of charge redistribution in molecules and materials with chemical sensitivity, atomic resolution, and orbital selectivity. The instrument will cover the soft x-ray range from 100 to 1000 electron volts using a high-power mid-infrared laser for harmonic generation. The combination of attosecond resolution, high flux, and elemental specificity will extend the x-ray spectroscopic capabilities into a new regime, leading to a unique multiuser instrument for novel insights into fundamental electronic processes, especially those involving correlated electron dynamics. The instrument will offer easy access and research training opportunities for students and early career researchers. The development project integrates transient x-ray absorption spectroscopy, photoelectron spectroscopy, streaking capabilities, and coincident charge particle imaging to serve a broad user base at the University of Arizona, as well as other scientists at the national level.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.