A study of three-dimensional structures of interplanetary dust by imaging x-ray microtomography.

通过 X 射线显微断层成像技术研究行星际尘埃的三维结构。

基本信息

批准号：
15340186
负责人：
TSUCHIYAMA Akira
金额：
$ 10.24万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Three-dimensional structures of cosmic dust (interplanetary dust particles and unmelted micrometeorites) and cometary dust that was collected by NASA Stardust mission were examined using x-ray microtomography at SPring-8. Three-dimensional structures with ultra-high spatial resolution of less than 100 nm has been obtained at the end of the term of this project by imaging tomography using attenuation contrast by overcoming troubles in an optical system for enlargement of x-ray beams and a sample rotation stage. We have also examined some samples by projection CT with the spatial resolution of about 0.5 μm. Physical properties of the samples, such as porosities and densities, were obtained from the three -dimensional structures of the cosmic dust samples. Furthermore, fractal dimensions of the samples were successfully obtained. The fractal dimensions of cosmic dust which was considered to be derived from comets are significantly less than 3. This may suggest evidence of aggregation of c … More onstituent particles of the dust in the early stage of the solar system. The Stardust sample analysis, which was performed as one of the members of preliminary examination team of Stardust, revealed the three-dimensional structures of impact tracks in aerogel collectors and terminal particles in the tracks. These results gave information about the impact processes as well as basic textural information for further detailed destructive analyses. Experimental studies of infrared spectrum of cosmic dust minerals in connection with infrared astronomical observation have been also made for comprehensive research on cosmic dust. Furthermore, development of the tomography system at SPring-8 and evaluation of its performance have been done. Brightness of CT images was quantitatively formulated. By using this formulation, we have established a technique for three-dimensional element mapping of Fe and Cs using the subtraction method. The results were applied to meteorites and other terrestrial samples as well as cosmic dust samples. Less

使用 SPring-8 的 X 射线显微断层扫描技术检查了 NASA 星尘任务收集的宇宙尘埃（行星际尘埃颗粒和未熔化的微陨石）和彗星尘埃的三维结构。通过克服X射线束放大和样品旋转的光学系统中的问题，通过使用衰减对比度的成像断层扫描，在该项目结束时获得了100 nm我们还通过投影CT检查了一些样品，从宇宙尘埃样品的三维结构中获得了样品的物理特性，例如孔隙率和密度。成功获得了被认为源自彗星的宇宙尘埃的分形维数明显小于 3。这可能表明尘埃成分颗粒聚集的证据。作为星尘初步检查小组成员之一进行的星尘样本分析，揭示了气凝胶收集器中撞击轨迹和轨迹中末端粒子的三维结构。还提供了有关撞击过程的信息以及进一步详细破坏性分析的宇宙尘埃矿物红外光谱的实验研究，以进一步对宇宙尘埃进行综合研究。 SPring-8 的断层扫描系统并对其性能进行了定量评估，通过使用该公式，我们建立了一种使用减法法进行 Fe 和 Cs 三维元素映射的技术。应用于陨石和其他陆地样本以及宇宙尘埃样本。