Development of a Small Angle X-ray Scattering Station for Dynamical Materials Studies and Education

这笔赠款支持康奈尔高能同步加速器源(CHESS)开发用于动力学材料研究和教育的小角X射线散射站(SAXS)。这个X射线站将是一个用户设备，用于研究材料的结构和动力学，特征尺寸从0.1到200纳米，时间尺度从亚毫秒到不确定。将探索的材料类型包括聚合物、纳米复合材料、大分子表面活性剂、树枝状大分子和有机-无机杂化薄膜。该设施将利用国际象棋公司的“G”摆动光束线产生的极高通量X射线束。G-LINE设备从一开始就被设计成提供稳定的、聚焦的、高强度的X射线束，通常会向样本提供每秒超过1015个光子的高通量。在如此高的通量下，在短至毫秒到微秒的时间内进行常规的原位测量颗粒大小、形状、晶格扭曲、应变和松弛、分子重新定向和完全相变变得切实可行。随着CHESS的摇摆器源产生极强的X射线束，这个新设施将显著提高国家从弱散射和快速变化的材料中收集高质量X射线数据的能力。要研究的材料类别--表面活性剂、树枝状大分子、聚合物、蛋白质和薄膜--属于传统上难以研究的“软物质”这一大类。这个新的SAXS设施正在康奈尔大学的中心校园建设，为本科生和研究生提供了一个在国家同步加速器中心长期参与和项目的难得机会。研究生需要帮助设计和建造这个设施，并完成他们自己的论文项目。这种全面的“动手”方法将使广大学生对X射线技术有深入的了解，并为未来的材料研究职业生涯提供彻底的科学家培训。

This grant provides support for the development of a small angle X-ray scattering station (SAXS) for dynamical materials studies and education at the Cornell High Energy Synchrotron Source (CHESS). This X-ray station will be a user facility to study the structure and dynamics of materials with feature sizes ranging from 0.1 to 200 nanometers and time scales ranging from sub-millisecond to indefinite. The types of materials that will be explored include polymers, nano-scale composites, macro-surfactants, dendrimers and organic-inorganic hybrid thin films. This facility will take advantage of the extremely high-flux X-ray beams produced by the "G" wiggler beamline at CHESS. Designed from the start to deliver stable, focussed, high intensity X-ray beams, the G-line facility will routinely deliver a high flux of more than 1015 photons per second onto a specimen. With such high fluxes it is becoming practical to perform, on times as short as milliseconds to microseconds, routine in-situ measurements of particle size, shape, lattice distortions, strain and relaxation, molecular reorientations, and complete phase transformations. With the extremely powerful X-ray beams from the wiggler source at CHESS, this new facility will significantly increase national capabilities to collect high quality X-ray data from weak scattering and rapidly varying materials. The classes of materials to be studied - surfactants, dendrimers, polymers, proteins and thin-films - fall into the broad class of "soft matter" that has traditionally been difficult to study. This new SAXS facility is being built on the central campus of Cornell University, providing a rare opportunity for undergraduate and graduate students to have long-term participation and projects at a national synchrotron center. Graduate students are expected to help design and build the facility as well as carry out their own dissertation projects. This overall 'hands-on' approach will give a broad group of students a deep understanding of X-ray techniques and provide a thorough training of scientists for future materials research careers.