Bremsstrahlung induced atomic processes

Abstract The observed spectra in the collisions of neon (Ne) projectiles of 1.8 and 2.1 MeV with an aluminum target (Al) have beensuccessfully segregated from strong bremsstrahlung backgrounds and then analyzed by comparing the transition energies andrates with the theoretical predictions of the flexible atomic structure code and the general-purpose relativistic atomic structurepackage. The spectra contain Kα , Khα , and Kαα lines. The Kαα emissions are due to two-electron one-photon transitions.Interestingly, the Kαα lines in projectile ions are only seen with 1.8 MeV energy. In contrast, the Kαα lines in the target ions arealso well observed with 2.1 MeV energy. Surprisingly, the Al K x-ray line intensities are strongly suppressed, and the Kαα lineintensities are unexpectedly enhanced. The underlying physical process is found to be the photoionization caused by intensebremsstrahlung radiation. This photoionization process converts most of the singly ionized K shell states (≈82% at 2.1 MeV)to doubly ionized K-shell states. This phenomenon is silently present on many occasions. We take some of such events tovalidate this remarkable finding. This bremsstrahlung radiation induced secondary ionization process stands as an eye openingincidence to the plasma physics, astronomy and astrophysics communities; may revolutionize these fields of research.