Development of x-ray diffractometer for petrographic thin section

本研究的目的是建立一种在光学显微镜下对岩相薄片上的小单晶进行X射线衍射数据采集的方法。2005年，新设计了一种用于将入射X射线聚焦到商业衍射仪的公共中心或Phi-X圆上的准直器，并被证实工作成功。2006年，在巴西Pocos de Caldas的霞石正长岩薄片上获得了小颗粒碱性角闪石晶体的X射线衍射数据，该数据发表在《矿物与岩石科学杂志》第99卷，第59-66页X射线数据通常是从相关物质的孤立颗粒中收集的，不需要考虑入射光线的宽度。然而，薄片上的颗粒并不是孤立的，而是具有邻近的晶体…周围有更多的谷粒。为了避免相邻颗粒的额外反射光束，应利用聚焦光线。为此，我们用0.2 mm的φ硅玻璃软管制作了准直器，并对样品进行了调焦，通常情况下，通过改变X射线的方向或倾斜的X射线和X射线的衍射来采集单晶的一整套X射线衍射数据。然而，在目前的情况下，这些射线的方向非常有限，因为样品下方的载玻片阻止了X射线的传播。为了克服这些限制，一位作者和他的同事开发了一种方法，该方法在Rigaku Denki期刊，第25卷，第1部分，PP3-9(1994)中有描述。根据该方法，将具有连续能谱的白X射线作为入射射线，并利用固态探测器来解析衍射X射线的能量。在倒置空间中的测量范围选择在圆锥体的内侧，圆锥体的轴线垂直于薄片表面，垂直角度为21度。将射程划分为12,227个小区域，计算各个区域的X射线衍射量。获得了1540个相关区域的显着衍射峰。在薄片上，晶体内部似乎仍存在很大的应力场。对测量数据的分析应在不久的将来进行

The purpose of this investigation is to establish a method of a collection of x-ray diffraction data from a small single crystal on the petrographic thin section which has been examined precisely under the optical microscope.In 2005, the collimator by which incident x-rays were focused on the common center or phi- and chi-circle of a comercial diffractometer was newly designed and has been confirmed to work successfully.In 2006, the x-ray diffraction data from a small grain of an alkali amphibole crystal on the thin section of nepheime syenite from Pocos de Caldas, Brazil, which was described in Journal of Mineralogical and Petrological Sciences, vol.99, pp59-66, 2004 by us were collected using the above mentioned diffractometer eauipped the collimator.X-ray data are usually collected from an isolated grain of the relevant material and it is not necessary to consider the breadth of the incident rays. However, the grain on the thin section is not isolated but has the neighboring crystal … More grains around it. In order to avoid the extra reflected beams from the neighboring grains, focused rays should be utilized. For this reason, a collimator has been made using a flexible silica-glass tube of 0.2mm φ and has been tuned to focus the concerning specimen.In usual case, a whole set of the x-ray diffraction data of a single crystal is collected by varying the directions or tne inciaent x-rays and the diffracted x-rays. In the present case, however, the directions of those rays are very restricted because the slide glass under the specimen prohibits the propagation of the x-rays. To overcome the restrictions one of the writer and his coworkers developed a method which was described in Rigaku Denki Journal, Vol.25, Part1, pp3-9 (1994). According to this method, the white x-ray having the continuous energy spectra as the incident rays and the solid state detector which was enable to resolve the energy of the diffracted x-rays. The measured range in the reciprocal space was selected to the inside of a cone of which axis was normal to the surface of the thin section and its vertical angle was 21 degrees. The range was divided to 12,227 small areas and the diffracted x-rays from individual area were counted. 1540 significant diffracted intensities from relevant areas were obtained. Very large stress field seemed to remain in the crystals on thin section. The analysis of the measured data should be performed in near future Less