Reflection due to fluorescence of a radiant energy flux impinging on a planar surface

In this paper, the authors describe a study of the manner in which L-K transitions reflect radiation impinging upon a plane layer of thickness l. They assume that the energy distribution of the incident photons is a Planck function. Fluorescence due to K-shell vacancies produced by photoionisation is the only effect taken into consideration. Fluorescence due to other inner-shell processes is neglected. They consider that the atoms of the materials have a K-shell binding energy much greater than those of the L or M-subshells. They also assume that the temperature of the blackbody spectrum is sufficiently high for K-shell ionizations. Moreover, the fluorescence yields due to other inner-shell vacancies are small. By solving the transfer equation, they shall be able to calculate the re-emitted flux and, consequently, the albedo of the layer. Photons with energy greater than the K-shell binding energy photoionize the K-shell of the atoms and induce immediate L-K transitions, thus causing emission of photons with energy hvKL = EK-EL or Auger electrons. They give numerical results to the case when the Auger effect is not taken into account. This neglect can be justified when induced processes are very important, They shall then compare the results with those obtained when account is taken of maximum ejections of Auger electrons