Seltzer S M
Ionizing Radiation Division, National Institute of Standards and Technology, Technology Administration, U.S. Department of Commerce, Gaithersburg, Maryland 20899.
Radiat Res. 1993 Nov;136(2):147-70.
Calculations of mass energy-transfer and mass energy-absorption coefficients for photon energies from 1 keV to 100 MeV have been developed, based on a re-examination of the processes involved after the initial photon interaction. The probabilities for the initial interaction are from the current photon interaction cross-section database at the National Institute of Standards and Technology. The calculations then take into account (1) electron binding effects on the Compton-scattered photon distribution; (2) the complete cascade of fluorescence emission after ionization events in any atomic subshell, including those associated with incoherent scattering and triplet production; and (3) the radiative energy losses of the secondary electrons and positrons slowing down in the medium, including the emission of bremsstrahlung, characteristic X rays from impact ionization, and positron in-flight as well as at-rest annihilation quanta. Consideration of the processes in (3) goes beyond the continuous-slowing-down approximation and includes the effects of energy-loss straggling. Results for the mass energy-absorption coefficient are compared with those from recent tabulations.
基于对初始光子相互作用后所涉及过程的重新审视，已针对1 keV至100 MeV的光子能量开展了质能传递系数和质能吸收系数的计算。初始相互作用的概率取自美国国家标准与技术研究院当前的光子相互作用截面数据库。这些计算随后考虑了以下因素：(1) 电子束缚对康普顿散射光子分布的影响；(2) 任何原子子壳层中电离事件后的完整荧光发射级联，包括与非相干散射和三重态产生相关的那些；(3) 次级电子和正电子在介质中减速时的辐射能量损失，包括轫致辐射的发射、碰撞电离产生的特征X射线、飞行中和静止时正电子的湮灭量子。对(3)中过程的考虑超出了连续慢化近似，并包括了能量损失离散的影响。将质能吸收系数的结果与近期表格中的结果进行了比较。
