NER: Novel Aerosol Spectrometer for Size and Composition of Nanoparticles

[403829 .巴克利]这项研究的目的是开发一种新型气溶胶光谱仪，它能够定量地测量悬浮气溶胶颗粒的大小和组成。尺寸选择将通过流体分离和电子迁移的组合来执行；粒子将在流动的流中带电和分离，使用为点光谱测量设计的可变电场。用双色紫外（UV）微激光诱导击穿光谱（u-LIBS）测定其成分。u-LIBS诊断头将选择性地对空间大小分离的气溶胶进行取样。光将被分散到一个新的梯级光谱仪中，该光谱仪带有CCD相机，可选的中继透镜增强器和高帧率。亚微米颗粒在许多科学领域都很重要，从开发具有不寻常特性的新材料，到制药应用，再到与人类发病率和死亡率有关的对环境具有重要意义的悬浮气溶胶颗粒。所有这些领域都迫切需要能够提供尺寸和成分信息的实时方法，这些方法的可用性将代表一种使能技术，可以催化我们对纳米级粒子科学的进一步了解。技术提案中概述的大气和燃烧气溶胶源分配的具体例子突出了所提议的气溶胶光谱仪可以为革命性的基础进步做出贡献的领域之一。有三个特定的创新领域有望为这种新的光谱仪设计提供改进的性能。它们是：1)结合流体和静电的颗粒大小分类耦合点光谱测量，2)使用UV u-LIBS提供高度空间分辨（因此尺寸分辨）的气溶胶诊断，与典型的LIBS安排相比，有可能提高检测限，3)使用敏感的，高帧率的梯级光谱仪在宽光谱范围内提供元素组成。允许几乎全部组成的测定和气溶胶种群中元素关联的鉴定。正如提案中详述的那样，(2)和(3)和都是特别高风险的。UV u-LIBS从未在气溶胶颗粒上尝试过，也不知道是否会产生预期的好处。此外，高帧率梯队光谱仪是一种新产品，其对该问题的适用性和灵敏度有待确定。以前对亚微米气溶胶颗粒的点尺寸和组成的方法取得了有限的成功，特别是对于小于300纳米的尺寸。提案中概述的方法有充分的理由和希望，但这显然是探索性研究。如果高风险的技术不能像预期的那样执行，低风险的选择可以确保项目产生有意义的结果。拟议的研究还将对光谱学和纳米尺度科学交叉学科的学生的教育和培训产生重大影响。由此产生的气溶胶光谱仪本身将为同时进行颗粒组成和大小分析的仪器提供重大改进，这将为教育和研究开辟新的途径。特别是，拟议的仪器可能对鉴定和最终减轻不健康的大气纳米粒子产生巨大影响。

0403829 Buckley The objective of this research is the development of a novel aerosol spectrometer that is able to quantitatively measure both size and composition of suspended aerosol particles. Size selection will be performed by a combination of fluidic separation and electronic mobility; particles will be charged and separated in a flowing stream using a variable electric field designed for point spectroscopy measurements. Composition determination will be accomplished with two-tone ultraviolet (UV) micro Laser-Induced Breakdown Spectroscopy (u-LIBS). The u-LIBS diagnostic head will selectively sample spatially size-segregated aerosol. Light will be dispersed into a new echelle spectrometer with a CCD camera, an optional relay lens intensifier and a high framing rate. Submicron particles are important in many areas of science, from the development of new materials with unusual properties, to pharmaceutical applications, to environmentally important suspended aerosol particles that are implicated in human morbidity and mortality. Real-time methods that can provide both size and composition information are urgently needed in all of these areas, and the availability of these methods would represent an enabling technology that could catalyze further advances in our understanding of nanoscale particle science. The particular example of atmospheric and combustion aerosol source-apportionment outlined in the technical proposal highlights one of the areas in which the proposed aerosol spectrometer could contribute to revolutionary fundamental advances.There are three specific areas of innovation that are expected provide improved performance for this new spectrometer design. They are:1) The combination of fluidic and electrostatic size classification of particles coupled for point spectroscopic measurement, 2) The use of UV u-LIBS to provide highly spatially-resolved (and thus size-resolved)aerosol diagnostic with potentially improved detection limits over typical LIBS arrangements, and 3) The use of a sensitive, high frame-rate echelle spectrometer to provide elemental composition over a wide spectral range, allowing nearly total composition determination and identification of elemental associations in the aerosol population. As detailed in the proposal, both (2) and (3) and are particularly high-risk.UV u-LIBS has never been attempted on aerosol particles, and it is not known if the expected benefits will accrue. In addition, the high frame-rate echelle spectrometer is a new product and its applicability and sensitivity for this problem has yet to be determined. Previous approaches to point sizing and composition of submicron aerosol particles have met with limited success, particularly for sizes below 300 nm. The approaches outlined in the proposal have strong justification and promise, but this is clearly exploratory research. Lower risk options are in place to ensure meaningful results from the project should the higher-risk technologies fail to perform as expected.The proposed research would also have a substantial impact on the education and training of students in the interdisciplinary intersection of spectroscopy and nanoscale science. The resulting aerosol spectrometer would itself provide significant improvement in the instrumentation available for simultaneous particle composition and sizing analysis, which would open new avenues in both education and research. In particular, the proposed instrument could have an enormous impact on the identification and eventual mitigation of unhealthy atmospheric nanoparticles.