Research in Secondary Ion and Neutral Mass Spectrometry

二次离子与中性质谱研究

• 批准号: 0135888
• 负责人: Emile Schweikert
• 金额: $ 41.75万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0135888&HistoricalAwards=false
• 关键词: Research; Secondary; Ion; Neutral; Mass

In research supported by the Analytical and Surface Chemistry Program, Professor Emile Schweikert and his coworkers at Texas A&M University are developing new methods for mass spectrometry of surfaces.The research focuses on extracting more information from the ejecta generated when bombarding surfaces with keV mono and polyatomic projectiles. One objective is to achieve nanophase characterization via the detection of coincidentally emitted secondary ions. The approach relies on the novel concept of "mass separated time-of-flight mass spectrometry". A second objective is to advance detection sensitivity, which translates into the requirement of detecting neutrals. The approach is to collisionally cool the desorbed neutrals at ambient pressure, collect them into a supersonic molecular beam and subject them to efficient hyperthermal ionization for subsequent identification by time-of-flight mass spectrometry. In addition to enhanced detection sensitivity, the procedure should be useful for surfaces not readily amenable to examination in vacuum.This project deals with advancing chemical analysis expertise for examining surfaces. Progress in surface science and technology with emphasis on nanostructures requires the detection of vanishingly small amounts of molecules. The research aims to enhance our capabilities for identifying the chemical makeup of nanostructures and for detecting small numbers of molecules dispersed on a surface. The work will focus on two novel methods of mass spectrometry. One based on "mass-separated time-of-flight mass spectrometry" is expected to enable chemical analysis of nanodomains as small as ~ 30 nm. The other involves "ambient pressure secondary neutral mass spectrometry" with the goal of detecting molecules when they are randomly distributed on a surface (rather than assembled in a nanostructure) and when they are present in amounts which cannot be detected with current techniques.

在分析和表面化学项目支持的研究中，德克萨斯农工大学的 Emile Schweikert 教授和他的同事正在开发表面质谱分析的新方法。该研究的重点是从用 keV 单原子和多原子射弹轰击表面时产生的喷射物中提取更多信息。 目标之一是通过检测同时发射的二次离子来实现纳米相表征。 该方法依赖于“质量分离飞行时间质谱”的新颖概念。 第二个目标是提高检测灵敏度，这转化为检测中性物质的要求。 该方法是在环境压力下碰撞冷却解吸的中性粒子，将它们收集到超音速分子束中，并对它们进行有效的超热电离，以便随后通过飞行时间质谱法进行识别。除了增强检测灵敏度之外，该程序还适用于不易在真空中检查的表面。该项目涉及先进的用于检查表面的化学分析专业知识。 以纳米结构为重点的表面科学和技术的进步需要检测极少量的分子。 该研究旨在增强我们识别纳米结构的化学组成和检测分散在表面上的少量分子的能力。这项工作将重点关注两种新颖的质谱方法。 一种基于“质量分离飞行时间质谱法”的技术预计能够对小至 30 nm 的纳米域进行化学分析。 另一种涉及“环境压力二次中性质谱法”，目的是检测分子随机分布在表面上（而不是组装在纳米结构中）以及分子的存在量无法用现有技术检测到的情况。