Collaborative Research: Midwest Low KV Collaboration: Continuation of Development of Low KV High Spatial Resolution EPMA Technique to Sub-micron Geological Features

合作研究：中西部低KV合作：继续开发针对亚微米地质特征的低KV高空间分辨率EPMA技术

• 批准号: 1849386
• 负责人: John Fournelle
• 金额: $ 25.09万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1849386&HistoricalAwards=false
• 关键词: Collaborative; Research; Midwest; Low; KV

This project involves development of new techniques in the use of the electron probe microanalyzer, to extend its usefulness in chemically analyzing smaller sized materials than previously possible. This instrument operates by focusing a beam of high energy electrons at a target sample inside a vacuum chamber, and then measuring the different X-rays inherently produced by this process. The rationale for this work is to better understand physical processes - both in geological and earth materials, but also in man-made materials at smaller and smaller scales - with a relatively simple instrument that is available in many universities, industrial and governmental research laboratories. Many times the very smallest features in a material can give critical information about how the material was created, and for manmade materials, how it will break or fail.In a just completed NSF-supported project (EAR-1554269), to develop a technique for extending the utility of the smaller electron beam field emission electron probe microanalyzer, we operated at lower accelerating voltage (i.e., 7 kV) vs traditional 15-20 kV. At these voltages, the higher energy K-series X-ray lines such those of the transition metals (e.g. Fe), are not generated - requiring that the lower energy L-series X-rays be measured and quantified. However, there are series difficulties with using these L-series X-rays, as they become complex entities due to spectral peak shift/shape changes, resulting from chemical bonding effects exacerbated by the adjacent absorption edge which adds more complexity. Thus, one single or simple reference standard is no longer a valid approach to quantification. In that project, we developed an innovative procedure to handle these iron L-alpha X-rays--and iron is an important element in many relevant geological materials. This research focused on the Fe-bearing mineral olivine and iron-silicides (found in meteorites and on the surface of the moon). This new project has several components to extend this technique: (1) extend this low kV Fe-L series work to other important important minerals such as sulfides, pyroxenes, garnets and amphiboles, (2) expand to look at L-lines of some Ni-bearing and Mn-rich minerals, (3) evaluate possible ways to improve measurements with "plasma" cleaning samples, (4) develop protocols using the innovative Soft X-ray Emission Spectrometer for the low energy X-rays generated at low kV, (5) investigate the feasibility of utilizing DFT (density functional theory) to simulate the complex spectral shapes of the L-series transition metals as well as the M-series of some rare earth elements (which have a similar set of conditions as the L-lines of Fe, etc.), and (6) investigate sample damage by the higher-electron-density field emission beam. This work will be done in a joint collaboration between the electron microprobe labs of the University of Wisconsin-Madison and the University of Minnesota-Minneapolis. The project will support a postdoctoral research fellow.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目涉及在使用电子探针微分析仪中开发新技术，以扩展其在化学分析较小尺寸的材料中的实用性，而不是以前。该仪器通过将高能电子的光束聚焦在真空室内的目标样品上，然后测量该过程固有产生的不同X射线。 这项工作的基本原理是更好地了解物理过程 - 无论是地质和地球材料，以及在越来越小的尺度上的人造材料中 - 具有相对简单的工具，该工具在许多大学，工业和政府研究实验室中都可以使用。很多时候，材料中最小的功能可以提供有关材料的创建方式，以及用于人造材料的关键信息，它将如何破裂或失败。 KV。在这些电压下，未产生较高的能量K系列X射线线，例如过渡金属的X射线线（例如Fe） - 要求测量和量化较低的能量L系列X射线X射线。但是，使用这些L系列X射线存在串联困难，因为它们由于光谱峰值移位/形状变化而变成复杂的实体，这是由于化学键合效应加剧了相邻的吸收边缘，从而增加了更复杂的性能。因此，一个或简单的参考标准不再是定量的有效方法。在该项目中，我们开发了一种创新的程序来处理这些铁L-alpha X射线 - 铁是许多相关地质材料的重要因素。这项研究的重点是含有富富的矿物橄榄石和铁硅化剂（在陨石和月球表面发现）。这个新项目具有多种扩展此技术的组件：（1）将这种低的KV FE-L系列工作扩展到其他重要的矿物质，例如硫化物，耐碳烯，石榴石和闪石，（2）扩展到查看某些含有Ni-bearing和Mn富裕矿物的L线，（3）评估使用“帕斯马”（4）的柔和方法，（3） （5）研究利用DFT（密度功能理论）的可行性来模拟L系列过渡金属的复杂频谱形状以及某些稀有接地元件的M系列的复杂光谱形状（这些条件与FE等范围相似的情况相似），并研究了较高的损坏。这项工作将在威斯康星大学麦迪逊分校和明尼苏达大学明尼苏达大学的电子微探针实验室之间进行联合合作。 该项目将支持博士后研究员。该奖项反映了NSF的法定任务，并被认为是使用基金会的知识分子优点和更广泛的影响评论标准的评估值得支持的。

项目成果

Electron probe microanalysis: A review of recent developments and applications in materials science and engineering

• DOI: 10.1016/j.pmatsci.2020.100673
• 发表时间: 2021-02
• 期刊: Progress in Materials Science
• 影响因子: 37.4
• 作者: X. Llovet;A. Moy;P. Pinard;J. Fournelle

ϕ ( ρz ) Distributions in Bulk and Thin Film Samples for EPMA. Part 1: A Modified ϕ ( ρz ) Distribution for Bulk Materials, Including Characteristic and Bremsstrahlung Fluorescence

EPMA 散装和薄膜样品中的 Ï ( Ïz ) 分布。

• DOI: 10.1017/s1431927620024915
• 发表时间: 2021
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: Moy, Aurélien;Fournelle, John
• 通讯作者: Fournelle, John

ϕ ( ρz ) Distributions in Bulk and Thin-Film Samples for EPMA. Part 2: BadgerFilm: A New Thin-Film Analysis Program

EPMA 散装和薄膜样品中的 Ï ( Ïz ) 分布。

• DOI: 10.1017/s1431927620024927
• 发表时间: 2021
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: Moy, Aurélien;Fournelle, John
• 通讯作者: Fournelle, John

Solving the iron quantification problem in low-kV EPMA: An essential step toward improved analytical spatial resolution in electron probe microanalysis—Olivines

解决低电压 EPMA 中的铁定量问题：提高电子探针微量分析中的分析空间分辨率的重要一步 – 橄榄石

• DOI: 10.2138/am-2019-6865
• 发表时间: 2019
• 期刊: American Mineralogist
• 影响因子: 3.1
• 作者: Moy, Aurélien;Fournelle, John H.;von der Handt, Anette
• 通讯作者: von der Handt, Anette