Acquisition of a Multi-Impact Position-Sensitive Detector for a Tomographic Atom-Probe: Atomic Scale Chemical Analysis

9625903 Seidman断层扫描原子探针（TAP）是原子探针场离子显微镜（APP 100或简称原子探针）的基本扩展，它提供一维原子分辨率深度剖析能力。 而TAP以0.2-0-5 nm的横向空间分辨率和等于沿被探测方向的面间距沿着的深度分辨率（0.2- 0.3nm）在直接晶格空间中产生三维（3D）化学分布。 技术咨询方案的主要特点是：具有原子尺度上的定量组成信息的亚纳米3D图像，具有100个阳极的多撞击位置敏感检测器（PSD），其允许每个场蒸发脉冲检测多达8个离子，1个离子脉冲-1的平均检测速率和100 Hz的脉冲频率，采用现代工作站，在三个小时内可以收集和分析一百万个单独的原子，具有直接晶格空间中的原子尺度图像的高质量分辨率（m/m = 200）。 没有其他仪器具有TAP的上述独特实验能力。 该奖项提供支持的收购多影响PSD，相关的数据采集电子设备，工作站，和先进的可视化程序，从收集的数据创建三维图像。 这个TAP将是一个名为“芝加哥地区原子尺度化学联盟”的设施的一部分;除了西北大学，伊利诺伊大学材料研究实验室和阿贡国家实验室的材料科学部门也参与其中。 拟议的研究中心围绕的问题，需要在原子尺度上的界面化学的知识，和化学信息与0.5-2纳米大小的原子核，形成在合金的分解技术的重要性。 ***

9625903 Seidman The tomographic atom probe (TAP) is a fundamental extension of the atom-probe field-ion microscope (APFIM or simply atom probe), which provides atomic-resolution depth profiling capability in one dimension. While the TAP yields three- dimensional (3D) chemical profiles in direct lattice space at a lateral spatial resolution of 0.2-0-5 nm, and a depth resolution equal to the interplanar spacing along the direction being probed (0.2-0.3 nm). The TAP's principal features are: subnanometric 3D images with quantitative compositional information on an atomic scale, multi-impact position sensitive detector (PSD) with 100 anodes that allows for the detection of up to 8ions per field- evaporation pulse, an average detection rate of 1 ion pulse -1 and a pulse frequency of 100 Hz, a million individual atoms can be collected and analyzed in three hours employing a modern work station, high mass resolution (m/m = 200) with atomic scale images in direct lattice space. There is no other instrument with the above unique experimental capabilities of the TAP. This award provides support for the acquisition of a multi- impact PSD, associated data acquisition electronics, a work station, and an advanced visualization program for creating 3D images from the collected data. This TAP will be part of a facility that is named "The Chicago-Area Consortium for Atomic-Scale Chemistry"; in addition to Northwestern University, the University of Illinois' Materials Research Laboratory and Argonne National Laboratory's Materials Science Division are involved. %%% The proposed research centers around problems that require a knowledge of interfacial chemistry on an atomic scale, and chemical information associated with 0.5-2 nm size nuclei that form in the decomposition of alloys of technological importance. ***