Enhanced damage induced by secondary high-energy electrons

A new kind of radiotherapy scheme based on the resonant Auger--interatomic Coulombic decay mechanism (RA ICD) was proposed in the work of Gokhberg et al. [Nature 505, 661 (2014)], which may effectively reduce the overall radiation dose in traditional x-ray radiotherapy. An electron produced in this scheme carries most of the energy of the primary x-ray photon. Through the present experiment using an energetic electron impact on a NeAr dimer, we demonstrate that three processes, namely, the interatomic Coulombic decay triggered by a Ne $2s$ electron ionization, ICD triggered by $\mathrm{A}{\mathrm{r}}^{+*}(3{p}^{4}nl\ensuremath{\ge}5d)$, and charge transfer in the $\mathrm{A}{\mathrm{r}}^{2+}\mathrm{Ne}$ ion, can take place and enhance the yields of slow electrons and ions. Therefore, energetic secondary electrons make the x-ray RA ICD scheme more toxic in radiotherapy.