MRI: Acquisition of a Small-Angle X-Ray Scattering Instrument

该提案寻求获得最先进的小角度x射线散射仪器。该仪器的配置，结合了旋转阳极源和两个独立的相机，已经精心设计了不同的用户群体，他们的兴趣包括蛋白质聚集，聚合物科学，沸石成核，DNA电泳和胶体科学。选择旋转阳极源，因为它的光束强度高，有利于分析散射弱的样品。双全角/广角（SA/WA）相机是一个强大的单元，非常适合多用户仪器。该相机采用线源，将更大的样本量暴露于入射光束，从而减少了数据采集所需的时间。双SA/WA相机可用于研究Bragg衍射以分析聚合物的结晶度，Kratky光学将使我们能够表征高达约1000 nm的结构域。专用的小角度相机，虽然更专业，为我们提供了二维成像的能力，散射各向异性的样品（如半结晶聚合物）和大范围的样品到探测器的距离（100-1000毫米），使其有可能观察一个相机上的大范围的散射角度。该仪器将位于化学部门的晶体和分子结构实验室（CMSL），并由材料表征设施（MCF）维护。MCF由科学与工程学院和研究副校长办公室支持，CMSL和MCF都有完善的基础设施，用于学生培训和仪器维护。该仪器的用户群体本质上是多学科的，包括来自化学工程、机械工程、化学、生物学、生物化学和生物物理学以及医学生物化学和遗传学的教员。这些研究人员的共同需求是了解用衍射或光谱学等方法无法探测的结构问题。这一文书将处理的具体问题包括：沸石成核和有机分子存在下其他复杂无机体系形成的机制2。浓缩体系中核壳颗粒和聚合物包覆颗粒的研究蛋白质和合成生物材料在溶液中的聚集行为生物膜组件和大分子的体外研究DNA电泳用凝胶孔结构的测定非晶与半晶聚合物的加工-性能关系[j]。枝晶材料中金属颗粒形成的无损分析该仪器将在几个层面上对德州农工大学产生积极影响。它将成为几个研究项目的焦点，并将为其他人目前的研究提供一个新的工具。该仪器可能是美国最好的实验室SAXS仪器之一，因此它也将增强我们在聚合物和胶体科学领域招募领先教师的能力。最后，这一工具将在两个方面对教育产生积极影响。鉴于该仪器的多用户性质，它将大量用于研究生和本科生的学生培训，大约有35名学生最初使用该仪器进行研究。第二，这个工具将被纳入我们中的一个人正在开发的课程中（D. F.尚茨）。由于目前校园内没有SAXS仪器，该仪器将填补德州农工大学基础设施的巨大空白，使研究和教育受益。

This proposal seeks the acquisition of a state-of-the art small-angle X-ray scattering instrument. The configuration of this instrument, combining a rotating anode source with two independent cameras, has been carefully designed around a diverse user community whose interests include protein aggregation, polymer science, zeolite nucleation, DNA electrophoresis, and colloidal science. A rotating anode source was chosen due to its high beam intensity, facilitating analysis of samples that scatter weakly. The dual all-angle/wide-angle (SA/WA) camera is a robust unit ideally suited for a multi-user instrument. This camera employs a line source exposing a larger sample volume to the incident beam subsequently reducing the time needed for data acquisition. The dual SA/WA camera can be used to study Bragg diffraction for analyzing crystallinity in polymers and the Kratky optics will allow us to characterize domains up to approximately 1000 nm in size. The dedicated small-angle camera, though more specialized, gives us the capability of two-dimensional imaging for samples that scatter anisotropically (e.g. semicrystalline polymers) and a wide range of sample-to-detector distances (100-1000 mm), making it possible to observe a wide range of scattering angles on one camera. The instrument will be located in the Crystal and Molecular Structure Laboratory (CMSL) in the Chemistry Department and maintained by the Materials Characterization Facility (MCF). The MCF is supported by the Colleges of Science and Engineering and the Office of the Vice President for Research, and both the CMSL and MCF have a well-developed infrastructure for student training and instrument maintenance. The user community for this instrument is inherently multidisciplinary, including faculty from Chemical Engineering, Mechanical Engineering, Chemistry, Biology, Biochemistry and Biophysics, and Medical Biochemistry and Genetics. The common need of these investigators is to understand structural issues that cannot be probed with methods such as diffraction or spectroscopy. Specific problems that will be addressed with this instrument include:1. mechanisms of zeolite nucleation and the formation of other complex inorganic systems made in the presence of organic molecules2. studies of core-shell particles and polymer-coated particles in concentrated systems3. aggregation behavior of proteins and synthetic biomaterials in solution4. in-vitro studies of biological membrane assemblies and macromolecules5. determination of pore structures in gels used for DNA electrophoresis6. processing-property relationships of amorphous and semi-crystalline polymers7. non-destructive analysis of metal particle formation in dendritic materialsThis instrument will positively impact Texas A&M at several levels. It will be a focal point of several research programs and will give others a new tool for their current research. The proposed instrument would likely be one of the best laboratory SAXS instruments in the United States, so it will also enhance our ability to recruit leading faculty in the areas of polymeric and colloidal science. Finally, this instrument will positively impact education in two ways. Given the multi-user nature of this instrument it will be heavily utilized in student training of both graduates and undergraduates, with approximately 35 students initially performing research with the instrument. Second, this instrument will be integrated into a course one of us is developing (D. F. Shantz). As there is currently not a SAXS instrument on campus, this instrument will fill a large void in the infrastructure at Texas A&M, with research and education benefiting.