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Dynamics of matter-, antimatter-atom collisions

Thesis/Dissertation ·
OSTI ID:5220618

Utilizing the classical trajectory Monte Carlo (CTMC) technique, the author has undertaken the first comprehensive study of antimatter-atom collisions in the intermediate velocity regime (1 to 7 a.u.). This work has elucidated the effects of varying projectile mass and sign of charge in the collisions of electrons, positrons, protons and antiprotons with helium and krypton. Using both a screened Coulomb potential and a newly implemented model potential approach he has calculated total and differential cross sections for single electron removal processes in these systems. By analysis of these cross sections and from a detailed examination of the individual CTMC trajectories, he has formulated a simple model of the collision dynamics which lead to the predicted, and observed, behavior of these collisions. For example, he has found that due to their smaller mass relative to protons, positrons may readily vector momentum match with an orbital electron, capturing it. Consequently, at large impact velocities, positrons are more likely to remove an electron by charge transfer than are equivelocity protons. Further, he has demonstrated that a resolution of the discrepancies which exist between the theoretical consensus and the existing experimental measurements of the positronium formation cross section can be accomplished by taking into account the lack of complete confinement of positrons scattered to large angles and the accompanying loss of positron flux.

Research Organization:
Missouri Univ., Rolla, MO (United States)
OSTI ID:
5220618
Country of Publication:
United States
Language:
English