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Stopping power for structured atomic projectiles in cold or ionized solids

Thesis/Dissertation ·
OSTI ID:7183181
A model was developed to evaluate the stopping power for structured (not fully stripped) ion projectiles in cold (neutral) or ionized targets. The dominant contribution is computed in the local plasma approximation (LPA) which averages the stopping power of a free-electron gas (FEG) over the electron distribution of the target. Projectile structure is introduced by taking into account the charge distribution about the intruding ion. Corrections for treating the target as a local FEG are treated through a binding parameter and comparison to an alternate atomic-target formulation. The binding parameter is observed to scale in size with the degree of target ionization. Secondary corrections (Barkas and Bloch terms, to correct for departures from pure Rutherford scattering and from plane wave scattering, respectively) are also included. Projectile structure is treated only approximately through point effective charges. Two alternate derivations of the bloch correction are seen to yield consistent results. Two forms of the Barkas term are considered: one including contributions from close collisions while the other does not. Inclusion of the Bloch correction limits the results to velocities that depend on both the projectile and target. Various projectile-target combinations were calculated. The results deviate from standard tabulations by a most about 15% (often much less).
Research Organization:
Michigan Univ., Ann Arbor (USA)
OSTI ID:
7183181
Country of Publication:
United States
Language:
English