MRI: Acquisition of a Local-Electrode Atom-Probe (LEAP) Microscope (An Atom-Probe Tomograph) For Three-Dimensional Nanoscale Characterization of Materials

要购买的仪器是层析原子探针，它提供了一个具有原子分辨率的重建晶格的三维图像，其中每个原子的化学特性！是确定的。所涉及的具体仪器是由威斯康辛州麦迪逊市imagago科学仪器公司制造的局部电极原子探针（LEAP）显微镜。该仪器的费用将由国家科学基金会的主要研究仪器（MRI）计划和海军研究办公室的DURIP计划共同承担。具体来说，美国国家科学基金会将提供50万美元用于购买该仪器，西北大学将提供21.4万美元的成本匹配基金。海军研究办公室将提供59万美元，另外还有来自西北大学的29.5万美元的成本匹配资金，用于仪器和辅助设备的总金额为159.9万美元。该仪器将成为西北大学原子探针断层成像中心（NUCAPT）的展示仪器，该中心由材料科学与工程系David N. Seidman教授领导。它将用于研究目的，如提案中所述，广泛的材料，也用于教育博士后，博士生和本科生，REU学生，在这种新的表征技术。局域电极原子探针（LEAP）显微镜提供了0.1 nm深度的空间分辨率和0.2至0.5 nm的横向分辨率；后者取决于所分析的特定晶体平面{hkl}。它提供了样品表面的广角视图，高达600到70度，并且能够在常规基础上检查给定样品的深度为2微米。样品可以以250,000 Hz的频率脉冲，以获得每小时超过5500万个原子的收集速率。因此，从单个样本中很容易获得1亿个原子的数据集。LEAP显微镜是一种超高真空仪器，在低于10（-10）托的环境压力下工作！． 标本交换系统将其6至12个标本存储在超高真空条件下，这允许在一天内快速交换标本。LEAP显微镜是计算机控制的，收集的数据可以在线分析，达到一定程度的细节，以评估一次运行的进度。此外，已经并正在开发软件来进一步处理收集到的数据，以获得最大量的物理信息。

The instrument to be purchased is a tomographic atom probe, which provides a three-dimensional image of a reconstructed lattice with atomic resolution where the chemical identity of each atom ! is identified. The specific instrument involved is a local-electrode atom-probe (LEAP) microscope manufactured by Imago Scientific Instruments of Madison, Wisconsin. The cost of this instrument is to be shared between the National Science Foundation's Major Research Instrumentation (MRI) program and the Office of Naval Research's DURIP program. Specifically, the NSF is to provide $500,000 toward the purchase of this instrument with $214,000 in cost matching funds provided by Northwestern University. The Office of Naval Research is to provide $590,000 with an additional $295,000 in cost matching funds from Northwestern University for a grand total o f $1,599,000 for the instrument and ancillary equipment. This instrument is to be the show case instrument of the Northwestern University Center for Atom-Probe Tomography (NUCAPT), which is directed by Professor David N. Seidman, Materials Science and Engineering Department. It will be used both for research purposes, as described in the proposal, for a wide range of materials , and also for the education of postdoctoral students, Ph.D. students, and undergraduate students, REU students, in this new characterization technique The local-electrode atom-probe (LEAP) microscope provides a spatial resolution in depth of 0.1 nm and a lateral resolution of 0.2 to 0.5 nm; the latter depends on the particular crystallographic plane, {hkl}, being analyzed. It provides a wide angle view of the surface of a specimen, upwards of 60o to 70o, and is capable of examining a given specimen on a routine basis to a depth of 2 micrometers. The specimen can be pulsed at a frequency of 250,000 Hz to obtain collection rates exceeding 55 million atoms per hour. Thus, data sets of 100 million atoms are readily obtained from a single specimen. The LEAP microscope is an ultrahigh vacuum instrument that operates at an ambient pressure below 10(-10) torr! . A specimen exchange systems perm its six to twelve specimens to be stored under ultrahigh vacuum conditions, which permits the rapid exchange of specimens during the course of a day. The LEAP microscope is computer controlled and the data collected can be analyzed on-line, to a certain level of detail, to evaluate the progress of a run. In addition, software has been and is being developed to further process the collected data to obtain the maximum amount of physical information.