X-Ray Induced Total Ionization of Air

Abstract

X-ray-induced total ionization of air is investigated by solving rate equations of atoms and ions of nitrogen and oxygen. Time distributions of components in the whole ionization process are given by recording respective number density. A clear population inversion is observed as we change the blackbody temperature <inline-formula> <tex-math notation="LaTeX">$T_{b}$ </tex-math></inline-formula> of the incident X-ray. Total ionization time <inline-formula> <tex-math notation="LaTeX">$t_{\mathrm{ end}}$ </tex-math></inline-formula> of the whole system and each ion succession is calculated. We find that <inline-formula> <tex-math notation="LaTeX">$t_{\mathrm{ end}}$ </tex-math></inline-formula> is sensitive to <inline-formula> <tex-math notation="LaTeX">$T_{b}$ </tex-math></inline-formula> of the incident X-ray and an optimal ionization temperature <inline-formula> <tex-math notation="LaTeX">$T_{\mathrm{ opt}}$ </tex-math></inline-formula> exists at which <inline-formula> <tex-math notation="LaTeX">$t_{\mathrm{ end}}$ </tex-math></inline-formula> reaches its minimum. We have given the <inline-formula> <tex-math notation="LaTeX">$T_{\mathrm{ opt}}$ </tex-math></inline-formula> of nitrogen and oxygen ionization, respectively. The result indicates that deviation from the <inline-formula> <tex-math notation="LaTeX">$T_{\mathrm{ opt}}$ </tex-math></inline-formula> will lead to a severe multiplication of total ionization time.