X射线在影象增强器中背向散射特性的研究

STUDY OF BACKSCATTERING PROPERTIES OF X-RAY IN INTENSIFIERS

本文用蒙特卡罗方法模拟了轫致辐射X射线在形象增强器中的背向散射特性．针对X线源管电压为30～120kV时的细致辐射入射，给出了背向散射光子的角分布及能谱分布；同时，还给出了背向散射光子的平均能量和平均出射角与管电压的关系以及吸收光子数和直透光子数与管电压的关系．结果表明，背向散射光子以铁的特征辐射光子为主，能量是7.112keV．随着管电压的增加，特征辐射光子数减少，而高能量的背向散射光子逐渐增多．

The backscattering properties of the bremsstrahlung X rays in the intensifier have been studied with Monte-Carlo calculations. The angular and the spectrum distributions of the backscattering radiation are presented in the case that a tube voltage of the X ray source is 45, 60, 7 5 and 90 kV,respectively. At the same time, dependence of the mean energy and the mean exit angle of the backscattered photons on a tube voltage has been given, and a relation of the absorbed and the transmitted photon number to a tube voltage is described. The results show that most of the backscattered photons are characteristic X rays of iron, energy of which is 7. 112keV, and that the characteristic photons decrease and the high energy photons increase gradually with rising of tube voltage.