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Journal of Astrophysics & Aerospace Technology | ISSN: 2329-6542 | Volume 6
Atomic and Nuclear Physics
4
th
International Conference on
October 26-27, 2018 | Boston, USA
Long term beam dynamics and ion kinetics in ultra-low energy storage rings
Alexander Papash
Karlsruhe Institute of Technology, Germany
E
lectrostatic storage rings operate at very low energies in the keV range and have proven to be invaluable tools for atomic and
molecular physics. Because of the mass independence of electric rigidity, these machines are able to store a wide range of
different particles, from light ions to heavy singly charged bio-molecules, opening up unique research opportunities. However, earlier
measurements have shown strong limitations on beam intensity, fast growth of beam size and decay of ion current, reduced lifetime of
ion beam. The nature of these effects has not been fully understood. Also a large variety of experiments in future generation ultra-low
energy storage and decelerator facilities including in-ring collision studies with a reaction microscope require a clear understanding
of the physical processes involved into the operation of such rings. Nonlinear and long-term beam dynamics studies in ultra-low
energy storage rings are presented on the examples of a number of existing and planned electrostatic storage ring facilities. The results
from simulations were benchmarked against experimental data of beam losses in the ELISA storage ring
[
S.P. Møller et al., Proceed
of the European Particle Accelerator Conference, Vienna, 2000, pp. 788–790)
]
. It was shown
[
1,2,3
]
that decay of beam intensity is
mainly caused by ion losses on ring aperture due to multiple scattering on residual gas. Beam is lost on electrostatic elements and
collimators due to small ring acceptance. Rate of beam losses increases at high intensities because of the intra-beam scattering effect
adds to vacuum losses. Detailed investigations into ion kinetics, under consideration of effects from electron cooling and multiple
scattering of the beam on a supersonic gas jet target, were carried out and yields a consistent explanation of the physical effects in
a whole class of ultra-low energy storage rings. The lifetime, equilibrium momentum spread and equilibrium lateral spread during
collisions with the target are estimated. Based on computer simulations, the conditions for stable ring operation with an extremely
low-emittance beam are predicted. Finally, results from studies into the interaction of ultra-low energy ions with a gas jet target are
summarized.
alexander.papash@kit.eduJ Astrophys Aerospace Technol 2018, Volume 6
DOI: 10.4172/2329-6542-C3-024
Figure 1: Computer simulations of O- ions decay in ELISA ring at 22 keV beam energy.