La Verne J A, Mozumder A
Radiation Laboratory, University of Notre Dame, Indiana 46556.
Radiat Res. 1992 Jul;131(1):1-9.
Differential and integral W-values for ionization in gaseous water for electron and proton irradiation have been analyzed from the theoretical point of view for consistency between ionization and total inelastic collision cross sections. For low-energy electrons, which are ubiquitous for all primary radiations, the experimental or compiled cross sections from different sources are sometimes not consistent with one another. A practical, self-consistent procedure is outlined in such cases. The high-energy asymptotic W-values for differential and integral ionization are calculated to be 33.7 and 34.7 eV, respectively, for electron irradiation and 34.6 and 32.5 eV, respectively, for proton irradiation. The computed variations of the W-values with energy are generally in good agreement with experiment. Integral primary W-values due only to the interactions between the incident particle and the water vapor are calculated to be 43.5 and 45.0 eV for electrons and protons, respectively, in the high-energy asymptotic limit.
从理论角度分析了电子和质子辐照气态水时电离的微分和积分W值，以确保电离截面和总非弹性碰撞截面之间的一致性。对于所有初级辐射中普遍存在的低能电子，不同来源的实验或汇编截面有时并不相互一致。在这种情况下概述了一种实用的自洽程序。计算得出，电子辐照时微分和积分电离的高能渐近W值分别为33.7 eV和34.7 eV，质子辐照时分别为34.6 eV和32.5 eV。计算得出的W值随能量的变化通常与实验结果吻合良好。在高能渐近极限下，仅由入射粒子与水蒸气之间的相互作用引起的积分初级W值，电子为43.5 eV，质子为45.0 eV。
