基于X射线衍射仪的X光晶体本征参量的标定

X光晶体本征参量的实验标定是准确鉴定X光晶体种类和品质,研制各种类型晶体谱仪,X光线谱定量测量和高分辨X光单能成像的基础.基于X射线衍射仪,通过制作平面晶体样品架,采取控制X射线管电源、滤波片选取和厚度控制等措施,极大地抑制了Cu-KJ3及韧致辐射,使X射线管光源Cu-Kα单能化,提出了用滤片作为光源单能化的判据.对X光线谱测量中常用的X光分光晶体季戊四醇PET(002)]的晶格常量2d和Cu-Ka能点的积分衍射效率R.进行了标定方法研究,其标定值分别为(0.87425±0.00042)nm和(1.759±0.024)×10-4 Rad.基于X射线衍射仪的X光晶体本征参量的精密实验标定方法既快速高效,且十分方便和灵活.通过更换衍射仪的X射线管靶材,采取类似方法,可以标定其它能点的晶体积分衍射效率,可为X光晶体的本征参量库提供更多的标定数据.

Calibration of Characteristic Parameters for X ray Plane Crystal on the Automatic X ray Diffractometer

X ray crystal characteristic parameters are the bases of identification of X ray crystal species and class, kinds of X ray crystal spectrometer fabrication, X ray lines intensity quantitative measurement and X ray monochromatic image diagnosis. On the automatic X ray diffractometer (XRD), based on stability and precision control of θ and 2θ goniometer, special plane crystal holder was made. Bremsstrahlung and Cu Kα line were attenuated for 5 orders by 40 μm thick Nickel filter, X ray sources was to be Cu Kα monochromatic source, and transmission power of filter was the criterion of Cu Kα monochromatic source. For X ray Pentaerythritol(002) plane crystal of Crystal lattice (2d) and integral reflective coefficient (Rc) of Cu Kα energy were calibrated, there are 2d=(0.87 425±0.00 042)nm, Rc=(1.759±0.024)×10－4 Rad respectively. This kind of experimental method is efficient and convenient on XRD in common laboratory. On XRD, other monochromatic X ray sources can be obtained by changing the material of X ray tube, and integral reflective coefficient of different energy will be obtained by the same way.