Development of a High Ionization Efficiency Molten Glass Ion Emitter

高电离效率熔融玻璃离子发射器的研制

• 批准号: 0651447
• 负责人: Lang Farmer
• 金额: $ 11.41万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0651447&HistoricalAwards=false
• 关键词: Development; Ionization; Efficiency; Molten; Glass

This project involves an evaluation of the use of electrochemical techniques to improve the efficiency of metal ion production of liquid glass ion emitters. Overall, the project is designed to allow thermal ionization mass spectrometry (TIMS) to generate higher precision elemental isotope ratio measurements than is currently possible for elements of geologic interest (such as Pb). In this project we will investigate the use of modern electrochemical techniques to increase the efficiency of molten glass ion emitters (aka "Si gel" ion emitters). Recent studies from the analytical chemistry community have provided new insights into the processes of ion emission from liquid glasses. These studies have suggested that under the operating conditions in mass spectrometer, metal dopants in borosilicate glass melts (including Pb and Ag) are dominantly present as neutral metal atoms. This opens the possibility that increasing the proportion of metal ions in the glass could result in a more intense emitted metal ion beam. Our work will involve exploring the electrochemical properties of molten glasses under high vacuum, the conditions experienced in the source of a thermal ionization mass spectrometer. We will use a vacuum chamber "test bench" retrofitted for electrochemical experiments and square wave voltammetry to assess the oxidation-reduction behavior of metals (Pb, Mo, Fe, Cu, etc.) doped in molten borosilicate glasses. The experimental apparatus has already by constructed and simple cyclic voltammagrams of molten borosilicate glasses have already been generated, demonstrating the feasibility of our approach. Our experiments will be used to determine the optimal electrode potentials required to produce sustained anodic currents in the molten glasses, the anodic currents corresponding to oxidation of the metal dopants. Armed with this information we will design and construct an electrochemical cell that can be used in our existing Finnigan-MAT 261 TIMS and determine if the anodic currents generated in the molten glasses result in increased ion emission from these glasses for various metal dopants. If successful, this project should lead to higher precision age determinations for geologic materials, using U-Pb techniques, and will have implications to other disciplines requiring high precision elemental isotopic ratio determinations, including biochemistry and nuclear forensics. Most of the work will be carried out as part of the dissertation research of a female, Hispanic PhD student in the Department of Geological Sciences, University of Colorado, Boulder.

该项目涉及使用电化学技术来提高液态玻璃离子发射器的金属离子生产效率的评估。 总的来说，该项目旨在使热电离质谱法（TIMS）产生比目前可能对地质元素（如铅）进行的更高精度的元素同位素比测量。 在这个项目中，我们将研究使用现代电化学技术来提高熔融玻璃离子发射器（又名“硅凝胶”离子发射器）的效率。 分析化学界最近的研究为液态玻璃离子发射过程提供了新的见解。 这些研究表明，在质谱仪的操作条件下，硼硅酸盐玻璃熔体中的金属掺杂剂（包括铅和银）主要以中性金属原子的形式存在。 这开启了增加玻璃中金属离子比例可能导致更强发射金属离子束的可能性。 我们的工作将涉及探索熔融玻璃在高真空下的电化学性质，在热电离质谱仪的源中经历的条件。 我们将使用一个真空室“测试台”改装的电化学实验和方波伏安法，以评估金属（铅，钼，铁，铜等）的氧化还原行为。掺杂在熔融硼硅酸盐玻璃中。 实验装置已经建成，并已产生简单的循环伏安熔融硼硅酸盐玻璃，证明了我们的方法的可行性。 我们的实验将用于确定在熔融玻璃中产生持续阳极电流所需的最佳电极电位，阳极电流对应于金属掺杂剂的氧化。 有了这些信息，我们将设计和构建一个电化学电池，可以在我们现有的Finnigan-MAT 261 TIMS中使用，并确定是否在熔融玻璃中产生的阳极电流导致从这些玻璃中增加离子发射的各种金属掺杂剂。 如果成功，该项目将导致使用U-Pb技术对地质材料进行更高精度的年龄测定，并将对需要高精度元素同位素比率测定的其他学科产生影响，包括生物化学和核法医学。 大部分工作将作为博尔德市科罗拉多大学地质科学系一名西班牙裔女博士生论文研究的一部分进行。