摘要
X射线在影像增强器中的散射是影响X射线影像增强器输出图像对比度和分辨率的主要因素。首先用MonteCsrolo方法模拟了轫致辐射X射线与影像增强器的输入转换屏 (CsI :Na)的作用过程 ,给出了透过转换屏的X射线的能谱。然后以无限大平面铁板作为增强器内电极和管壳的几何模型 ,以CsI:Na的透过X射线能谱为铁板模型的入射能谱 ,分析了X射线在影像增强器中的背向散射特性。X射线管电压为 2 0～12 0kV ,转换屏厚度范围为 2 0 0～ 4 0 0 μm。结果表明 ,随着X射线管电压的升高 ,背向散射光子数增加 ,其平均能量也迅速增加 ;转换屏越厚 ,背向散射光子数越少。
The interaction processes of bremsstrahlung X rays with CsI:Na scintillator of different thickness(200～400 μm) are first simulated by means of Monte Carlo analysis. The energy spectra of exit photons from CsI:Na are presented, which are used as the incident spectra on iron, the constituents of the inner electrodes and shell of intensifiers. The backscattering properties of X rays in intensifiers are analyzed. The potential producing bremsstrahlung X rays is 20～120 kV. Results show that with the increase of X ray tube potential the number of backscattered photons gets bigger and their mean energies increase rapidly. [
出处
《计算物理》
CSCD
北大核心
2000年第3期298-306,共9页
Chinese Journal of Computational Physics
基金
SupportedbytheNationalNaturalFoundationofChina
关键词
影像增强器
轫致辐射
背向散射
X射线
bremsstrahlung
backscattered radiation
Monte Carlo method [CLC number] O242\^2[Document code]\ A
