Differential cross sections for the multiple ionization of Ne and Ar by protons

Journal Article · Sun Oct 31 23:00:00 EST 1993 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.48.3689· OSTI ID:6130499

Gonzalez, A D; Pedersen, E H ^[1]

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1. Institute of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

Differential cross sections [ital d][sigma][sup [ital q]+]([ital E],[ital cphi])/[ital d][Omega] for multiple ionization of Ne and Ar by protons have been measured for final charge states [ital q]=1--6, impact energies [ital E]=0.4--3 MeV, and scattering angles [ital cphi]=0.28--6.5 mrad. Within these ranges of energies and scattering angles, the angular dependence of the differential cross section for single ionization at constant energy follows a power law, [ital d][sigma][sup +]/[ital d][Omega][proportional to][ital cphi][sup [minus][ital k]]. The power [ital k] is found to be near 3.8 for Ne and 3.65 for Ar. A monotonic increase of all the [ital multiple]-[ital ionization] cross sections [ital d][sigma][sup [ital q]+]/[ital d][Omega], q[ge]2 relative to the [ital single][minus][ital ionization] cross section [ital d][sigma][sup +]/[ital d][Omega], is observed for increasing scattering angle. This behavior is most likely due to the combined effect of two multiple-ionization mechanisms. At the most distant collisions, the multiple ionization is dominated by the direct removal of valence electrons by the projectile. At the closest collisions, inner-shell ionization, followed by vacancy cascades, adds to the production of high-charge states. For Ne, this interpretation is supported by qualitative agreement with a model calculation based on the assumption that the multiple ionization of each shell follows binomial statistics. Quantitative agreement between experiment and theory requires a more thorough analysis of the many-body problem.

• OSTI ID: 6130499
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 48:5; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
BEAMS
CHARGE STATES
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELEMENTS
ENERGY RANGE
FLUIDS
GASES
ION COLLISIONS
ION-ATOM COLLISIONS
IONIZATION
MEV RANGE
MEV RANGE 01-10
NEON
NONMETALS
NUCLEON BEAMS
PARTICLE BEAMS
PROTON BEAMS
RARE GASES