Exponential Projectile Charge Dependence ofAr KandNe KX-Ray Production by Fast, Highly Ionized Argon Beams in Thin Neon Targets

Studies of neonL-shell excitation by impact of highly ionized heavy ions

“…The present experiments were undertaken to examine cross-sections for L-sheU excitation in neon by impact of highly charged heavy ions, to compare such target excitation spectra with the beamfoil spectra corresponding to comparable ionization states [2], to explore the projectile charge state effect [-3] in L-shell excitation, to study possible resolution advantages recoil ion spectroscopy has over beam-foil spectroscopy for equivalent collimation, to examine the question of possible higher n level electron excitation accompanying inner shell excitation, and to verify the absence of collisional quenching effects on excited levels of sufficiently short lifetime. These experiments were in large part motivated by the discovery that impact of suitable, highly ionized, foil-transmitted heavy ions generate very high ionization-excitation states [3]. For example, substantial amounts of Lyman alpha from hydrogenic Ne 9+ appeared in the target ion excitation spectrum when Ar q+ ions from the Oak Ridge Isochronous Cyclotron in the range q > 16 were used as projectiles, even under single collision conditions.…”

Double effects of projectile charge state on Nb L-shell ionization by slow highly ionized Xe ions

“…The radiative decay of the 2p vacancies is followed by the target L-shell X-ray emission. On the other hand, it is worth noting that the electron binding energy I 4d (Xe q+ ) will become larger as the charge state q grows [2,4,18], as indicated by the right side arrow in Fig. 4.…”

“…Based on the preceding physical process and the procedure presented by Warczak et al [19], the fraction of vacancies N(q) in the 4f MO, which qualitatively reflects Nb L-shell ionization cross sections variation tendency, can be expressed as N(q) ϭ cq 4d (q)W(q) (2) where c is a statistical factor, denoting the number ratio of the 4d to 4d orbitals; W(q) describes the 4d-4f transition probability. According to Lennard et al [17],…”

“…In ion-atom collision, inner-shell ionization following the heavy ion-solid surface interaction usually shows a strong monotonic increase with the projectile charge state. The charge state effect has attracted much attention [2][3][4][5][6][7][8][9][10]. For slow nearly symmetric or fully symmetric collisions, electron promotion with coupling molecular orbitals allows a successful qualitative description of this effect [11][12].…”

Projectile Charge-State Dependence ofNe K-Shell Ionization and Fluorescence Yield in 50-MeVCln++Burch1, Stolterfoht2, Schneider3 et al. 1974Phys. Rev. Lett.56030View full textAdd to dashboardCite

“…Macdonald et al} and Mowat et al 2 * 3 have recently reported that x-ray production cross sections in heavy-ion collisions at a fixed energy increase rapidly with the projectile charge state: In 80-MeV Ar +Ne and 50-MeV Cl + Ne collisions the x-ray cross sections rise exponentially with the incident charge state above 6+. This important discovery clearly showed the need for more detailed studies of the ionization mechanisms in heavy-ion collisions, and placed severe limitations on the interpretation of solid-target x-ray studies since they measure only the effects of an equilibrium charge-state distribution.…”