Monte Carlo simulation of the cascade decay processes in gaseous boron initiated by photons with energies scanned through L- and K-ionization thresholds

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2012-07, Vol.45 (13), p.135003-1-8
• Main Authors: Brühl, S, Kochur, A G
• Format: Article
• Language: English
• Subjects: Boron; cascade decay; Cascades; Computer simulation; Density; electron-impact ionization; Energy of formation; Mathematical analysis; Monte Carlo methods; photoionization; Photons; radiation effect on matter
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/0953-4075/45/13/135003

The Monte Carlo technique is applied to simulate the processes of the cascade relaxation of gaseous boron at atomic density of 2.5 × 1022 m−3 ionized by photons with the energies of 0.7-25 Ryd passing through a cylindrical interaction zone along its axis. The trajectories of electrons are simulated based on photoionization and electron-impact ionization cross sections calculated in the one-electron configuration-average Pauli-Fock approximation. Numbers of electrons and photons leaving the interaction zone per one initial photoionization, their energy spectra, the energy transferred to the medium and the probabilities of final ion formations are shown to change noticeably as the incident photon energy is scanned through boron atom ionization thresholds. These variations can be explained only if secondary electron-impact-produced processes are considered. The density of secondary events decreases when going from the zone axis to its border, and the profiles of the density along the radial direction are found to be similar for all the initial exciting photon energies.