MRI: Development of an Ultrafast Electron Microscope with <1nm-ps Spatio-Temporal Resolution

点击翻译按钮获取中文摘要

Technical AbstractA collaboration of scientists will develop a functional prototype ultrafast electron microscope (UEM) with less than 1nm-ps space-time resolution at the University of Illinois at Chicago (UIC). To achieve this improvement over current instrumentation technology by three orders of magnitude, several existing state-of-the-art technologies will be combined: a high-power, 1-100MHz, femtosecond laser system will be used to generate an initially spatially coherent electron pulse from a large-area nano-patterned photocathode; a short (20cm) microscope column, if necessary incorporating an RF pulse compression cavity, will be coupled to the objective, sample stage, and projector system of an available decommissioned JEOL JEM 100CX electron microscope; and the generated electron images will be detected using 10um-pore micro-channel plate electron detector optically-coupled to a 25um-pixel, 1kx1k, CCD camera - providing the potential of atomic resolution. The unprecedented space-time resolution afforded by the development of this UEM will clearly provide an important new research tool for a diverse and interdisciplinary set of research fields: molecular biology, catalysis, condensed matter and materials physics, and nanoscience and nanotechnology. Once developed, the world-wide scientific community will have access to the instrument through the Research Resources Center at UIC; thus, also facilitating new collaborative research between institutions and providing unique educational opportunities for students. Lay AbstractThe direct visualization of dynamic phenomena has historically led to a deeper understanding of the fundamental properties and physical laws of nature. On the nanoscale (dimensions more than 1000 times smaller than the diameter of a hair), these rudimentary dynamics often occur on very short timescales; typically requiring observation with a temporal resolution of better than a picosecond (the time taken by light to travel the thickness of a business card). By combining state-of-the-art short-pulse laser and electron microscope technologies, the collaboration centered at the University of Illinois at Chicago aims to develop an "ultrafast electron microscope" with the unprecedented space-time resolution required to study the basic transient properties of individual nanoscale systems for the first time. The future availability of such an instrument to scientists will lead to significant advances in the important area of nanoscience and nanotechnology; for example, by determining the operation of catalysts (both biological and chemical) to improve their efficiency and by elucidating the influence of defects (or nanoscale interfaces) on the properties (e.g., strength) of modern materials under dynamic stress. The interdisciplinary aspect of both in the instrument development and its use will also provide important and valuable educational opportunities for graduate and undergraduate students alike - the nation's future scientific and technological human resource.