High energy ion channeling: Principles and typical applications Cohen, C.; Dauvergne, D.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms,
08/2004, Letnik:
225, Številka:
1
Journal Article, Conference Proceeding
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The paper presents a review on selected aspects of high-energy ion channeling. Ion trajectories and fluxes are obtained in the frame of the `continuum model', in which atomic strings or planes are ...considered as uniformly charged objects. Computer simulations treating the consecutive binary collisions are also presented. Some typical applications are described, which take mostly benefit of the development of a highly non-uniform ion flux strongly peaked far from the heart of target atoms. These applications concern of course particle–matter interactions through, for instance, refined studies of the impact parameter dependence of energy loss and of charge exchange processes. They also concern material and surface science or nuclear physics, through lattice location measurements.
We present a review of the channeling and blocking experiments that have been performed at GANIL during the 30 years of stable beam operation, with the strong support of the multi-disciplinary ...CIRIL-CIMAP laboratory. These experiments combine atomic physics, solid state physics and nuclear physics.
The results of two channeling experiments show that highly charged heavy ions at moderate velocities (v<<Zv{sub 0}) may lose more energy in the traversal of a thin crystal when they are injected ...along a major crystallographic direction than when they traverse the crystal in random conditions. This is due to the fact that the large reduction of electron capture probabilities allows them to keep their high electronic charge throughout the crystal, which is not the case for projectiles traveling in random conditions. Although channeled projectiles experience reduced electron densities, their energy loss rate, that is, at first order, proportional to the square of the ions charge, is then strongly enhanced. This feature could be used as a step for decelerating highly charged ions from the high energies that are needed to produce them, and also to improve our understanding of the slowing down of very highly charged projectiles at low velocities, for which the current perturbative models are not well suited.
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