Advancing Soft X-ray Spectromicroscopy

在接下来的5年里，我们的研究将加强两种软x射线显微镜技术的仪器，技术和分析软件-扫描透射x射线显微镜（STXM）和平面摄影。（一）提高空间分辨率；（ii）在2D中提供更精确的空间分辨化学制图（iii）设计最小化辐射损伤的方法，包括低温冷却和压缩感知（一种新的图像获取方法）。我们将利用这些改进的能力来研究(a)在工作条件下（operando）的CO2电还原催化剂；(b)趋磁细菌对单晶磁铁矿的胞内生物矿化机制；(c)全球硫和碳循环耦合的同向性海洋细菌-古菌群落S 1s边缘的硫形态形成。我们的长期目标是开发新的或改进的软x射线显微镜技术，以及新的应用类别。在未来5年内，我们将：(1)在加拿大光源（CLS）和法国同步加速器Soleil完成ptychography（一种在STXM中提高空间分辨率的方法）的开发；(2)开展CO2电还原催化剂的原位和操作电化学STXM研究；(3)在2021年秋季安装新的单色仪后，帮助重新调试CLS软x射线显微镜光束线，这将在2000 - 3500 eV范围内的能量范围内提供超过一个数量级的性能改进。(4)利用新仪器开展生物地球化学研究，特别是利用S 1s边缘（2460 eV）分析与气候变化相关的系统中硫的形态。科学地说，这项研究计划将为能源材料领域提供重要的新知识。我们将提供二氧化碳电还原新催化剂的直接化学表征，这是一种回收二氧化碳的方法。在生物学领域，我们将提供更多关于细胞内磁铁矿的生物矿化的信息，通过趋磁细菌和新发现的原生生物物种（第一个发现的真核细胞产生细胞内磁铁矿链）。在这项研究中开发的改进的STXM和体表能力将影响许多加拿大和国际研究人员的研究，特别是那些希望超越静态样品的成像和光谱，研究系统在温度、湿度、电流、化学反应等因素影响下如何变化的研究。我们的仪器和技术发展将在CLS上发表在出版物和会议上，并通过我开发并不断改进的光谱显微镜软件包aXis2000提供。通过解决挑战当前软x射线显微镜能力的具体项目，我的小组的研究显着推进了该领域，并使CLS软x射线显微镜设备，加拿大这类研究的首要系统，走在前列。

Over the next 5 years our research will enhance instrumentation, techniques and analysis software for two soft X-ray microscopy techniques - scanning transmission X-ray microscopy (STXM) and ptychography. We will (i) improve spatial resolution; (ii) provide more accurate spatially resolved chemical mapping in 2D (iii) devise methods to minimize radiation damage, including cryo-cooling and compressive sensing, a novel image acquisition method. We will use these improved capabilities to study (a) catalysts for CO2 electro-reduction under working conditions (operando); (b) mechanisms of intracellular biomineralization of single crystal magnetite by magnetotactic bacteria, and (c) sulfur speciation at the S 1s edge of syntropic marine bacterial-archae consortia which couple global sulfur and carbon cycles. Our long-term objectives are to develop new or improved soft x-ray microscopy techniques, and new classes of application. In the next 5 years we will: (1) complete development of ptychography (a method of enhancing spatial resolution in STXM) at the Canadian Light Source (CLS) and at Synchrotron Soleil in France; (2) carry out in situ and operando electrochemical STXM studies of CO2 electro-reduction catalysts; (3) help re-commission the CLS soft X-ray microscopy beamline after a new monochromator is installed in fall 2021, which will give more than an order of magnitude improvement in performance at energies in the 2000 - 3500 eV range. (4) carry out bio-geo-chemical studies with the new instrumentation, in particular use the S 1s edge (2460 eV) to analyze sulfur speciation in systems relevant to climate change. Scientifically this research program will provide important new knowledge in the energy materials sector. We will provide direct chemical characterization of new catalysts for CO2 electro-reduction, a method of recycling CO2. In the biological arena we will provide additional information on biomineralization of intracellular magnetite by magnetotactic bacteria, and a newly discovered protist species (first eukaryotic cell found which makes chains of intracellular magnetite). The improved STXM and ptychographic capabilities developed in this research will impact studies by many Canadian and international researchers, in particular those who wish to go beyond imaging and spectroscopy of static samples, to studies of how systems change under the influence of factors such as temperature, humidity, electrical currents, chemical reactions etc. Our instrumentation and technique development will be made available at CLS presented in publications and conferences and through aXis2000, the spectromicroscopy software package that I developed and continue to improve. By tackling specific projects which challenge current soft X-ray microscopy capabilities, my group's research significantly advances the field, and keeps the CLS soft X-ray microscopy facility, Canada's premier system for such studies, at the forefront.