Purchase of X-ray powder diffractometer

我们正在申请资金购买另一台X射线粉末衍射仪。短期内，我们使用两个工具获取数据的能力将显著增强，而从长期来看，随着旧工具变得越来越不可靠，我们将拥有备用工具的安全性。粉末衍射的原理如下。X射线波长、衍射角和晶体中原子的平面间距之间的关系很简单。使用衍射仪，了解前两种情况可以测量后一种情况。从粉末衍射图中的峰可以获得两种基本类型的信息：(I)峰位置是晶胞大小和对称性的函数，以及(Ii)峰强度是晶胞中原子的类型和排列的函数。根据这些数据，我们可以确定粉末中存在的晶相，计算晶胞的尺寸，评估结构中的应变程度，并确定构成衍射图的所有相的平均微晶尺寸。此外，使用Rietveld方法，我们可以准确和精确地测量包括非晶态材料在内的所有相的相对丰度。这种测量对矿物学、岩石学和材料科学都是至关重要的。X射线粉末衍射是下列项目的必要工具：应用Rietveld方法识别和测量各种地质、工业和环境不友好材料中的矿物丰度，预测采矿活动对环境的影响，如酸性岩石排水，将人为二氧化碳固定在尾矿中，确定目前未知的矿物结构，新型纳米材料、合金和陶瓷的结构表征，以及确定和表征与加拿大天然气和重油加工业相关的新型催化剂。该仪器将使不列颠哥伦比亚省的电子微束/X射线衍射设备显著提高我们为研究人员以及加拿大矿物和材料行业提供的服务的数量、质量和稳定性。

We are requesting funds to purchase another X-ray powder diffractometer. In the short term, our capability to acquire data will significantly increase with two instruments, and in the long term, we will have the security of a backup instrument as the old one becomes increasingly unreliable. The principles of a powder diffraction are as follows. The relationship between X-ray wavelength, diffraction angle, and the spacing of planes of atoms in crystals is simple. Using a diffractometer, knowledge of the first two allows measurement of the latter. Two basic types of information can be obtained from the peaks in a powder diffraction pattern: (i) the peak positions are a function of the size and symmetry of the unit cell, and (ii) the peak intensities are a function of the types and arrangement of atoms in the unit cell. From these data we can identify the crystalline phases present in a powder, calculate the dimensions of the unit cells, assess the degree of strain in the structure, and determine the average crystallite size of all the phases contributing to the diffraction pattern. In addition, using the Rietveld method, we can accurately and precisely measure the relative abundances of all the phases present, including amorphous material. Such measurements are of crucial importance to mineralogy, petrology and the materials sciences in general. X-ray powder diffraction is an essential tool for the following projects: application of the Rietveld method to identify and measure the abundance of minerals in diverse geological, industrial and environmentally unfriendly materials, prediction of environmental impacts of mining activities such as acid-rock drainage, sequestration of anthropogenic CO2 in mine tailings, determining the structures of minerals that are presently unknown, the structural characterization of novel nanomaterials, alloys and ceramics, and to identify and characterize new catalysts relevant to Canada's natural gas and heavy oil processing industries. This instrument will allow the Electron-Microbeam/X-Ray Diffraction Facility at UBC to significantly improve the quantity, quality and stability of our services to researchers, and to the minerals and materials industry in Canada.