SST: Development of a Micro Mass Spectrometer and the Design of a Spectrometer-Based Distributed Sensor Network

设计、开发和测试一种微制造、小型化的磁扇形质谱仪（“微型质谱仪”），其质量分辨率为1原子质量单位（amu），质量范围为1 - 300 amu，对化学物质的灵敏度为十亿分之一（ppb）。还将设计专门用于这种光谱仪系统的分布式传感器网络。微质谱计的使能组件是微制造的碳纳米管场增强电离源和离子光学透镜，并设计使离子束与衬底表面平行而不是垂直。电子冲击电离和场电离阵列都将被研究。提议的工作将集中在开发和测试该设备在气相环境传感中的应用。该团队由来自杜克大学和微电子研究与发展机构MCNC-RDI的一组科学家组成。杜克大学的科学家带来了表面科学、场发射和气相化学方面的专业知识，并将与MCNC-RDI的研究人员协同工作，后者提供MEMS设计和微制造、传感器开发和真空微电子方面的专业知识。关于知识价值，主要的新颖性和设备概念如图1所示，图1显示了所提出的微型质谱仪的示意图和所演示的场发射设备的SEM显微照片。除了设计、开发和微制造这种重要的传感器及其各种组件外，所提出的研究将能够调查相同微系统中场发射器和场电离阵列之间微妙而重要的差异。电子场发射阵列将通过电子冲击电离和解离间接产生离子，并将具有能量和压力依赖关系。更高的能量和压力将导致更多的气体解离，在探测器上产生离子碎片。相比之下，电场增强的直接电离预计对能量和压力都不太敏感，超过特定的电离阈值。除了电极材料和几何形状之外，对这些参数及其对气相动力学和电离的综合影响的基础研究将有助于更好地理解传感器设计和探测器优化。就更广泛的影响而言，本提案侧重于环境气体传感应用；然而，通过适当的源特性和系统设计，该技术可以用于从化学战剂检测到生物医学诊断的各种应用。此外，这项研究创造的技术平台，一个片上离子和/或电子工作台，可以应用于许多广泛的应用，包括微型航天器的离子推进，小型化x射线管，紫外线光源和微波设备。该计划的成功完成将导致对微尺度气相电离，反应动力学和离子测量的新的基本理解，以及使分析和检测气体环境中的化学物质的新范式的发展。

0428540GlassThe design, development, and testing of a microfabricated, miniaturized magnetic sector mass spectrometer ("micro mass spectrometer") with a mass resolution of 1 atomic mass unit (amu), a mass range of 1 - 300 amu, and a sub part-per-billion (ppb) sensitivity to chemical species is proposed. The design of a distributed sensor network specifically for a system of such spectrometers will also be undertaken. The micro mass spectrometer has, as its enabling component, a icrofabricated, carbon nanotube (CNT) field-enhanced ionization source and ion optic lens, and designed so that the ion beam is oriented parallel, not perpendicular, to the substrate surface. Electron impact ionization and field ionization arrays will both be investigated. The proposed effort will focus on the development and testing of this device for applications in gas-phase environmental sensing. The team is comprised of a group of scientists from Duke Universityand MCNC-RDI, a microelectronics research and development institute. Scientists at Duke University bring expertise in surface science, field emission, and gas phase chemistry and will work in tandem with researchers at MCNC-RDI, who offer expertise in MEMS design and microfabrication, sensor development, and vacuum microelectronics. With respect to intellectual merit, the prime novelty and device concept are conveyed in Figure 1, showing a schematic representation of the proposed micro mass spectrometer and an SEM micrograph of a demonstrated field emission device. In addition to the design, development and microfabrication of this important sensor and its various components, the proposed research will enable an investigation of the subtle and important differences between field emitter and field ionization arrays within the same microsystem. An electron field emitter array will generate ions indirectly through electron impact ionization and dissociation and will have both energy and pressure dependences. Higher energies and pressures will lead towards more dissociation of the gaseous species, producing ion fragments at the detector. In contrast, direct, field-enhanced ionization is expected to be less sensitive to both energy and pressure, above a specific ionization threshold. A fundamental study of these parameters in addition to electrode materials and geometries and their combined effects on gas phase kinetics and ionization will lead to a greater understanding of sensor design and detector optimization. With respect to broader impact, this proposal focuses on environmental gas sensing applications; however with proper source characterization and system design, the technology can be used in applications ranging from chemical warfare agent detection to biomedical diagnostics. Also, the technology platform created by this research, an on-chip ion and/or electron workbench, can be applied to a number of far ranging applications, including ion propulsion for miniature spacecraft, miniaturized X-ray tubes, UV light sources, and microwave devices. The successful completion of this program will lead to a new fundamental understanding of microscale gas phase ionization, reaction kinetics, and ion measurement, as well as enabling the development of a new paradigm for analyzing and detecting chemical species in gaseous environments.