Transition from heating to cooling of channeled ion beams
- Schonland Research Institute for Nuclear Sciences, University of the Witwatersrand, Johannesburg (South Africa)
Experiments showing a transverse heating or cooling of channeled ion beams are explained in terms of electron capture and loss processes between the projectile ions and the target. Such processes violate reversibility as the projectile captures electrons from occupied bound states and loses them to unoccupied weakly bound or continuum states. The transition probabilities for the transfer of electrons are calculated in the impact parameter Born approximation. Their dependence on the distance from the crystal strings is determined by scale factors which depend in turn on the relative velocity and the binding energies of the transferred electrons in the projectile and in the crystal, respectively. The appearance of transverse heating and cooling depends on the relative size of the scale factors for capture and loss. The transition from heating to cooling as function of velocity is described in good agreement with the experiments.
- OSTI ID:
- 20787517
- Journal Information:
- Physical Review. A, Vol. 73, Issue 6; Other Information: DOI: 10.1103/PhysRevA.73.062901; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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