Advancing Soft X-ray Spectromicroscopy

我的小组开发新的仪器，技术和应用内壳激发光谱和光谱显微镜。我们使用这些方法来研究广泛的化学，环境，能源科学和纳米材料系统。我们的强项是对内壳激发光谱如何取决于材料的化学结构和物理性质有一个基本的理解，然后将这些知识用于分析具有技术和社会重要性的材料和工艺。我们的研究范围从小分子类似物的实验和计算研究（例如CF 3SO 3 H作为燃料电池膜中质子传输磺酸盐位点的类似物），到探索软X射线光谱显微镜的新颖和具有挑战性的应用，这通常需要开发新的检测方案和原位方法。 在过去的5年里，扫描透射X射线显微镜（STXM）已成为我们的主要研究工具。在接下来的五年里，我们将进一步扩大X射线光谱显微镜仪器和技术在加拿大光源（CLS，萨斯卡通）和先进光源（ALS，伯克利），并利用新的仪器广泛的科学。在CLS，我们正在建立一个全新的STXM，致力于使用cryo-spectro-tomography和cryo-spectro-ptychography测量定量3D化学分布。Ptychography是一种革命性的X射线成像新方法，它通过测量样品上重叠点阵列处的相干衍射图案，然后使用先进的相位恢复方法创建图像，从而大大提高了空间分辨率。空间分辨率为1.5 nm的软X射线重叠最近实现。相比之下，STXM的分辨率通常为30 nm，最多为15 nm，采用最先进的光学器件。新的cryo-STXM将用于帮助改进汽车应用背景下的燃料电池材料及其制造工艺，并研究趋磁细菌等生物系统。我们还将进行金属沉积过程的原位流体流动和电化学研究（与半导体器件工艺相关），并使用原位流动和电位偏差来可视化肽-脂质相互作用，以了解阳离子抗菌肽的抗菌活性机制。在ALS，我们正在开发光谱重叠关联分析在燃料电池和趋磁细菌样品中的应用。

My group develops novel instrumentation, techniques and applications for inner-shell excitation spectroscopies and spectromicroscopies. We use these methods to study a wide range of chemical, environmental, energy sciences, and nanomaterials systems. Our forte is developing a fundamental understanding of how inner shell excitation spectra depend on the chemical structure and physical properties of a material, and then to use that knowledge for analysis of materials and processes of technological and societal importance. Our research ranges from experimental and computational studies of small molecule analogs (e.g. CF3SO3H as an analog to the proton transport sulfonate site in fuel cell membranes), to exploring novel and challenging applications of soft X-ray spectromicroscopies, which often require the development of new detection schemes and in situ methods. Over the past 5 years, scanning transmission X-ray microscopy (STXM) has become our major research tool. In the next five years, we will further expand X-ray spectromicroscopy instrumentation and techniques at the Canadian Light Source (CLS, Saskatoon) and the Advanced Light Source (ALS, Berkeley) and exploit the new instrumentation for a wide range of science. At CLS we are building a radically new STXM dedicated to measuring quantitative 3D chemical distributions using cryo-spectro-tomography and cryo-spectro-ptychography. Ptychography is a revolutionary new approach to X-ray imaging which greatly improves spatial resolution by measuring coherent diffraction patterns at an array of overlapping points on the sample and then creating the image using advanced phase retrieval methods. A spatial resolutions of 1.5 nm was recently  achieved with soft X-ray ptychography. In contrast, STXM resolution is routinely 30 nm and at best, 15 nm with state-of-the-art optics. The new cryo-STXM will be used to help improve fuel cell materials and their manufacturing processes in the context of automotive applications, and to investigate biological systems such as magnetotactic bacteria. We will also perform in situ fluid flow and electrochemical studies of metal deposition processes (relevant to semiconductor device processes), and use in situ flow and potential bias to visualize peptide - lipid interactions relevant to understanding mechanisms of antimicrobial activity of cationic antimicrobial peptides. At the ALS we are developing applications of spectro-ptychography to fuel cell and magnetotactic bacteria samples.