On the Continuous Slowing Down Approximation for the Degradation Spectra of Secondary Electrons

Abstract

Abstract The degradation spectra of secondary electrons produced in helium irradiated with high energy electrons have been calculated by two methods. In the first method, the direct integration of the basic formula was carried out and in the second one, the continuous-slowing-down-approximation (CSDA) was used. When the energy of incident electrons is 1 keV (1 eV=9.648×104 J/mol), the second method gave a G-value of ionization, 2.17, while the first method gave 2.29. With the decrease in the energy of incident electrons, the CSDA was found to become less reliable. With the incident electrons of 100 eV, the error in the G-value of ionization exceeded 15%. The implication of these calculations to the theoretical treatment of the initial process of radiation chemistry is discussed. As an example, the spatial distribution of ion-pairs in γ-irradiated water has been recalculated.