Addressing Unsolved Questions on Weathering of Surfaces in Space by Fast Solar Particles

该项目旨在促进对来自太阳的快速带电粒子(离子)轰击太空表面的影响的科学理解。这种影响包括侵蚀以及化学成分和外观的变化。这些研究将在实验室进行，条件类似于没有大气层的天文天体。这些天体的例子是月球和小行星，它们是计划中的人类太空任务的主题。这些研究的结果将推动基础科学的发展，但也将适用于新能源技术；例如，离子轰击会污染和限制核聚变反应堆的寿命。该项目的结果也与先进材料的研究有关；例如，快离子的侵蚀在制造高温氧化物超导体和用于微电子和光子学的薄电介质方面具有实际意义。这项研究将对学生和博士后研究人员进行一套独特的实验技术培训。这项研究将是迄今为止最准确地再现风离子对月球、小行星和其他内太阳系无空气天体表面的影响的研究。实验室研究将使用超高真空、现场化学分析和质量选择离子束。我们将使用多种表面分析技术和光学光谱技术来检查月壤、陨石和简单矿物的样本。要定量研究的基本现象包括溅射(高能离子抛射原子和分子)、元素和化学成分的变化以及光学反射率的变化。该项目将检查离子注入引起的化学反应，包括辐射增强的水溶液变化，量化产生的挥发物，并测量溅射侵蚀和再沉积的程度。这项研究将首次使用质子和氦离子同时照射，以揭示协同效应；覆盖着薄冰的样品将模拟可能在小行星上发生的界面化学反应；元素和化学成分的现场检查，包括陨石样品中碳质球粒陨石的表面。这项关于辐射增强水溶液蚀变的研究有望帮助解释小行星谷神星，这是美国宇航局目前黎明任务的目标。该项目还将涉及研究生培训。

This project seeks to advance the scientific understanding of the effect of bombardment of surfaces in space by fast charged particles (ions) from the Sun. Such effects include erosion as well as changes in both the chemical composition and the appearance. The studies will be done in the laboratory, in conditions similar to those existing in astronomical bodies without atmosphere. Examples of these bodies are the Moon and asteroids, which are the subject of planned human space missions. The results from the studies will advance science at the fundamental level but also will be applicable to new energy technologies; ion bombardment, for example, contaminates and limits the life of nuclear fusion reactors. The project results are also relevant to the studies of advanced materials; erosion by fast ions, for example, is of practical importance in the fabrication of high-temperature oxide superconductors and in thin dielectrics for use in microelectronics and photonics. The research will involve training of students and postdoctoral researchers in a unique set of experimental techniques.The study will be the most accurate to date in reproducing the effects of the wind ions on the surface of the Moon, asteroids and other airless bodies in the inner solar system. The laboratory studies will use ultrahigh vacuum, in situ chemical analysis, and mass-selected ion beams. We will examine samples of lunar soils, meteorites and simple minerals using multiple surface analysis techniques and optical spectroscopy. The basic phenomena to be studied quantitatively include sputtering (the ejection of atoms and molecules by energetic ions), changes in elemental and chemical composition, and changes in optical reflectance. The project will examine chemical reactions induced by implanted ions, including radiation-enhanced aqueous alteration, quantify the volatiles produced, and measure the magnitudes of sputter erosion and re-deposition. For the first time, the studies will use simultaneous irradiation with both protons and helium ions, to unveil synergistic effects; irradiation of samples coated with thin ice will simulate interfacial chemical reactions that may occur in asteroids; in situ examination of elemental and chemical composition, including surfaces of carbonaceous chondrites in meteoritic samples. The study on radiation-enhanced aqueous alteration is expected to aid interpretation of asteroid Ceres, a target of the current Dawn mission of NASA. The project will also involve graduate student training.