Technician Support for Geoscience Research in Transmission Electron Microscopy

0113345商业这笔赠款为一名电子显微镜操作员提供部分工资支持，他将帮助最大限度地发挥两台电子显微镜的地质、矿物学和地球化学能力，这两台电子显微镜将于2001年安装在亚利桑那州立大学高分辨率电子显微镜中心内。获得这些仪器是为了在材料科学和物理领域开发新的技术和测量，新职位的目标是熟悉这些技术，并使其适用于地质科学的研究。其中一台仪器的电子束可以小于0。直径2 nm。我们将利用这一能力在原子尺度上分析晶界、位错核和表面层，并将通过电子纳米衍射从单胞内获得结晶学数据。另一台仪器将包含一个Gatan成像滤光片，用于测量，允许在亚纳米尺度上进行元素测绘。它还将有一个环境单元，用于在受控大气下进行研究。这种小室将在样品室中保持相对较高的气体压力，最高可达50托，同时保留了透射电子显微镜的高分辨率能力。样品加热和动态图像记录将允许在接近原子规模的情况下进行化学反应。我们将用它来研究在电子显微镜的真空中不稳定的矿物。这些包括粘土矿物、绿色铁锈、石膏和相关的水合硫酸盐以及矿物中的脱羟基反应和价态变化。

0113345BuseckThis grant provides partial salary support for an electron microscopist who will help maximize the geological, mineralogical, and geochemical capabilities of two TEMs that will be installed in 2001 within the ASU Center for High Resolution Electron Microscopy. These instruments were obtained to develop new techniques and measurements in materials science and physics, and the goal of the new position is to become familiar with those techniques and adapt them for research in the geological sciences. One of the instruments will have an electron beam that can be made less than 0. 2 nm in diameter. We will use this capability to analyze grain boundaries, dislocation cores, and surface layers on the atomic scale and will obtain crystallographic data from within unit cells through electron nanodiffraction. The other instrument will contain a Gatan imaging filter for measurements that will allow elemental mapping on the sub-nanometer scale. It will also have an environmental cell for studies under controlled atmospheres. This cell will maintain a relatively high gas pressure of up to 50 torr in the sample chamber, while retaining the high-resolution capabilities of the TEM. Specimen heating and dynamic image recording will allow chemical reactions to be followed at close to the atomic scale. We will use this to study minerals that are unstable in the vacuum of the electron microscopes. These include clay minerals, the green rusts, gypsum and related hydrated sulfates as well as dehydroxylation reactions and valence changes in minerals.***