Ion and photon beam interactions with atoms and materials: fundamentals and inter-disciplinary applications including chemical analysis on the Martian surface

离子和光子束与原子和材料的相互作用：基础知识和跨学科应用，包括火星表面的化学分析

• 批准号: RGPIN-2019-03901
• 负责人: Campbell, John
• 金额: $ 2.99万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714516
• 关键词: Ion; photon; beam; interactions; atoms

My inter-disciplinary program has four linked strategic directions. The first two are the basic physics of X-rays and the applied physics of materials analysis using X-ray detection technology. These have supported our development and application of particle-induced X-ray emission (PIXE) analysis, which uses high-energy proton beams to induce materials of interest to emit X-rays, whose “signatures” and intensities reveal the elements present and their concentrations. We have also developed a software package “GUPIX” for PIXE analysts, supplying it to 180 research labs in 51 countries. It is PIXE that has led my group into its fourth research area - participation in NASA's Mars Science Laboratory (MSL) mission, which seeks evidence for pre-existing life on Mars. The Guelph-based alpha-particle X-ray spectrometer (APXS) on the Curiosity rover uses both PIXE and a second technique (X-ray Fluorescence or XRF) to analyze Martian rocks, sands and soils. Together with the various other instruments on Curiosity, this helps build a picture of the evolution of the geology of the Martian surface over billions of years. Of especial interest is the study of minerals and their element content for evidence that water has been present, since water is a crucial component for life. An example of our current work is the problem of partial dust cover on Martian rocks, as seen in images taken by Curiosity's cameras. This dust, which we have succeeded in analyzing by collecting a wind-blown sample, causes error in the APXS analysis. We have developed a new approach to the data analysis that enables us to separate out the effects of dust cover and thus permit analysis of the substrate rock. This is a significant step towards better accuracy. We are also refining the method so that it can also analyze thin films deposited on rock surfaces by fluids in the distant past. Recently we built and tested a lab-based PIXE system that emulates APXS, giving us the ability to rapidly analyze large suites of rock samples from terrestrial formations that appear similar in geology to formations seen on Mars. Together with computer simulation, this PIXE system is helping us to improve the accuracy of APXS analysis. The issue of accuracy has brought us back to our long-term work on the basic physics of PIXE. Collaboration is now in progress with research institutes in Croatia and Slovenia to improve the database which underpins the method.

我的跨学科计划有四个相互关联的战略方向。前两个是X射线的基础物理和使用X射线检测技术的材料分析的应用物理。这些都支持了我们的粒子诱导X射线发射（PIXE）分析的开发和应用，该分析使用高能质子束诱导感兴趣的材料发射X射线，其“签名”和强度揭示了存在的元素及其浓度。我们还为PIXE分析师开发了一个软件包“GUPIX”，并将其提供给51个国家的180个研究实验室。 正是PIXE带领我的团队进入了第四个研究领域--参与美国宇航局的火星科学实验室（MSL）使命，寻找火星上先前存在生命的证据。位于圭尔夫的阿尔法粒子X射线光谱仪（APXS）使用PIXE和第二种技术（X射线荧光或XRF）来分析火星岩石，沙子和土壤。与Curtain上的其他各种仪器一起，这有助于构建数十亿年来火星表面地质演变的图像。 特别令人感兴趣的是研究矿物质及其元素含量，以证明水的存在，因为水是生命的重要组成部分。 我们目前工作的一个例子是火星岩石上部分灰尘覆盖的问题，正如Curtain相机拍摄的图像所示。我们通过收集风吹样品成功地分析了这种灰尘，这会导致APXS分析中的错误。我们开发了一种新的数据分析方法，使我们能够分离出灰尘覆盖的影响，从而允许分析基底岩石。这是迈向更高准确性的重要一步。我们还在改进这种方法，以便它也可以分析在遥远的过去由流体沉积在岩石表面的薄膜。 最近，我们建立并测试了一个基于实验室的PIXE系统，该系统模拟了APXS，使我们能够快速分析来自陆地地层的大型岩石样本，这些岩石样本在地质学上与火星上看到的地层相似。结合计算机模拟，该PIXE系统有助于提高APXS分析的准确性。准确性问题使我们回到了PIXE基础物理学的长期工作中。目前正在与克罗地亚和斯洛文尼亚的研究机构进行合作，以改进作为该方法基础的数据库。