Crystallographic studies on interplanetary dust particles

行星际尘埃粒子的晶体学研究

• 批准号: 06044217
• 负责人: OHSUMI Kazumasa
• 金额: $ 2.05万
• 依托单位: National Laboratory for High Energy Physics
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044217/
• 关键词: Interplanetary dust particles (IDPs); Micro-crystal; Structure refinement; Crystal textures; Synchrotron radiation; Laue method

Interplanetary dust particles (IDPs) are considered to hold the information of an early stage of solar system. NASA/Johnson Space Center has collection of IDPs, and made preliminary investigation of them by the methods of electron prove micro analysis as well as observation through electron microscope. According to their size, X-ray diffraction method has not been applied on them. Therefore, crystallographic information are kept unknown.At the Photon Factory (PF), a system to analyze a sub micrometersized crystal has developed by using synchrotron radiation (SR) with Laue method. In order to obtain crystallographic information of IDPs, this system is applied to them. The colaborative study is performed by an aid of this International Scientific Research Program.Six IDPs were selected at NASA/JSC and then examined by SR at PF in this year are silicates, sulfides and alloys of which sizes are from eight to nineteen micrometers in diameter.Almost all samples give the complicated Laue patterns showing polycrystalline states with diffuse Laue spots or complete powder lines.As the first step of the crystallographic studies, the indices are assigned to Laue spots of the comparatively good sample ( (Fe, Ni) S) , and the structure refinement is now carried out based on Laue intensities.

行星际尘埃颗粒被认为是太阳系早期的信息来源。NASA/约翰逊航天中心收集了大量的内流离失所者，并通过电子显微镜观察和电子探针显微分析的方法对他们进行了初步的研究。根据其大小，X射线衍射法尚未应用于它们。在光子工厂（PF），利用同步辐射（SR）和劳厄方法开发了一套分析亚微米晶体的系统。为了获得晶体学信息的IDP，该系统被应用到他们。合作研究是在国际科学研究计划的帮助下进行的。今年在NASA/JSC选择了六个IDP，然后由PF的SR检查，它们是硅酸盐，大多数样品都具有复杂的劳厄花样，表现为多晶状态，劳厄斑点或完整的粉末线弥散分布，这是晶体学研究的第一步研究中，指数被指定为相对较好的样品（（Fe，Ni）S）的劳厄斑点，并且现在基于劳厄强度进行结构精修。