A tomography device based on a conventional laboratory x ray source, polycapillary parallel x ray lens(PPXRL), and polycapillary collimating x ray lens(PCXRL) is designed. The PPXRL can collect the divergent x ray beam from the source and focus it into a quasi-parallel x ray beam with a divergence of 4.7 mrad.In the center of quasi-parallel x ray beam, there is a plateau region with an average gain in power density of 13.8and a diameter of 630 μm. The contrast of the image can be improved from 28.9% to 56.0% after adding the PCXRL between the sample and the detector.
为了优化多毛细管X光透镜的设计,利用旋转坐标系的方法建立子管方程,根据光线追迹原理建立了X射线在导管中传输的模型,直接求解一元四次方程得到X射线每次反射时与管壁的交点,从而追踪单根X射线的运动轨迹,并由大量X射线的总的运动规律得到X射线在单根导管中的传输规律,再由单根导管拓展到整个透镜。在此基础上编写程序,实现了对X光透镜的传输效率和光斑的模拟计算。为了验证模拟的准确性,对两个平行束透镜分别进行了实验测试和模拟。在8.05 ke V下,所测的传输效率为13.0%,模拟计算结果为14.2%。在对光斑的模拟中,模拟所得的光斑也与实验结果相符合。结果表明,模型的建立是合理的,在类似透镜的设计制造中有着潜在应用。
