Structural Study of Plastic Crystals by Use of an Area Detector.

当使用光刺激荧光粉屏（称为成像板）的x射线区域探测器应用于衍射图样为连续和扩散的样品的强度测量时，它作为二维探测器显示出极大的实用性。对于漫射和各向异性衍射图的强度测量，例如塑料晶体的衍射图，面积检测器是必不可少的。首先应用面积探测器（DIP100, MAC Science）测量了液体CCl_4和H_2O的x射线散射强度。本实验的散射强度与用能量色散法测定的散射强度进行了比较。不同方法测得的强度吻合较好。实验证明，利用该探测器可以用简单的分析方法，以较短的积累时间精确地测量光晕图案的散射强度，并且在高散射角下，散射x射线的斜入射对IP没有影响。其次，测量了室温下塑性结晶金刚烷（C_<10>H_<16>）单晶的衍射图样。它们包含劳厄斑点、各向异性和漫射散射模式。C_<10>H_<16>的分子似乎在fcc晶格点上有较大的振动运动。

When an area detector for X-rays using a photostimulable phosphor screen, called "an imaging plate (IP)", is applied to the intensity measurement of the samples whose diffraction pattern is continuous and diffuse, it exhibits greatly the usefulness as the two-dimensional detector. The area detector is especially indispensable for the intensity measurement of a diffuse and anisotropic diffraction pattern, for example the diffraction pattern from plastic crystals.First the area detector (DIP100, MAC Science) has been applied to the intensity measurements of X-ray scattering from liquids CCl_4 and H_2O. The scattering intensities in the present experiments have been compared with that determined by means of an energy-dispersive method. The intensities obtained by the different methods have agreed well with each other. It has been proved that the use of the IP detector makes it possible to measure the scattering intensities of halo patterns precisely with much shorter accumulating time with a simple procedure of analysis and that there is no effect of the oblique incidence of scattering X-rays to the IP at high scattering angles.Next diffraction patterns from a single crystal of adamantane (C_<10>H_<16>), which is plastic crystal at room temperature, have been measured. They have contained Laue spots and anisotropic and diffuse scattering patterns. It seems that the molecules of C_<10>H_<16> make a large librational motion on the fcc lattice points.