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，结合了两个独立的摄像机旋转阳极源，已经精心设计了不同的用户社区，其利益包括蛋白质聚集，聚合物科学，沸石成核，DNA电泳和胶体科学。选择旋转阳极源是因为其高光束强度，便于分析散射弱的样品。双全角度/广角（SA/WA）摄像头是一款坚固耐用的单元，非常适合多用户仪器。该相机采用线源，将较大的样品体积暴露于入射光束，从而减少数据采集所需的时间。双SA/WA相机可用于研究布拉格衍射，以分析聚合物中的结晶度，Kratky光学器件将使我们能够表征尺寸高达约1000 nm的域。专用的小角度相机虽然更专业，但为我们提供了对各向异性散射的样品（例如半结晶聚合物）进行二维成像的能力，并且样品到检测器的距离范围很广（100-1000 mm），从而可以在一台相机上观察到广泛的散射角度。该仪器将位于化学系的晶体和分子结构实验室（CMSL），并由材料表征机构（MCF）维护。MCF由科学和工程学院以及研究副总裁办公室支持，CMSL和MCF都有完善的基础设施用于学生培训和仪器维护。该仪器的用户社区本质上是多学科的，包括化学工程，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师。这些研究人员的共同需求是了解无法用衍射或光谱等方法探测的结构问题。该文书将处理的具体问题包括：1. 沸石成核机理和其他复杂无机体系的形成， 有机分子的存在2. 浓缩体系中核壳粒子和聚合物包覆粒子的研究3. 蛋白质和合成生物材料在溶液中的聚集行为4. 生物膜组件和高分子的体外研究5. 用于DNA测序的凝胶中孔结构的测定6. 无定形和半结晶聚合物的加工性能关系7. 树枝状材料中金属颗粒形成的非破坏性分析该仪器将在多个层面上对德克萨斯A M产生积极影响。它将成为几个研究项目的焦点，并将为其他人的当前研究提供新的工具。拟议中的仪器可能是美国最好的实验室SAXS仪器之一，因此它也将提高我们在聚合物和胶体科学领域招募顶尖教师的能力。最后，这一文书将从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，最初约有35名学生使用该仪器进行研究。第二，这个工具将被整合到我们中的一个正在开发的课程中（D。F. Shantz）。由于目前校园里还没有SAXS仪器，该仪器将填补德克萨斯A M基础设施的一个巨大空白，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.