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

要购买的仪器是一个断层原子探针，它提供了一个三维图像的重建晶格与原子分辨率，其中每个原子的化学身份！被识别。 所涉及的特定仪器是由威斯康星州的麦迪逊的Imago Scientific Instruments制造的局部电极原子探针（LEAP）显微镜。该仪器的成本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计划分摊。具体来说，NSF将提供50万美元用于购买该仪器，西北大学提供了21.4万美元的成本匹配资金。 海军研究办公室将提供590，000美元，并从西北大学获得额外的295，000美元的成本匹配资金，用于仪器和辅助设备，总计1，599，000美元。该仪器将成为西北大学原子探针层析成像中心（NUCAPT）的展示仪器，该中心由大卫N。Seidman，材料科学与工程系。它将用于研究目的，如提案中所述，用于广泛的材料，也用于博士后学生的教育。学生，本科生，REU学生，在这个新的表征技术 局部电极原子探针（LEAP）显微镜提供了0.1 nm的深度和0.2至0.5 nm的横向分辨率的空间分辨率;后者取决于特定的晶面，{hkl}，正在分析。它提供了一个样品表面的广角视图，高达60 o至70 o，并能够在常规基础上检查给定的样品，深度为2微米。样品可以在250，000 Hz的频率下脉冲，以获得超过每小时5500万个原子的收集速率。因此，1亿个原子的数据集很容易从单个样品中获得。LEAP显微镜是一种可在低于10（-10）kPa的环境压力下工作的真空仪器。.一个样本交换系统可以在超真空条件下储存6到12个样本，这样可以在一天内快速交换样本。LEAP显微镜由计算机控制，收集的数据可以在线分析，达到一定的细节水平，以评估运行的进度。此外，已经并正在开发软件，以进一步处理收集到的数据，以获得最大数量的物理信息。

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.