Berlin 2001 – scientific programme
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A: Atomphysik
A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)
A 10.6: Poster
Wednesday, April 4, 2001, 12:30–15:00, AT3
Collective Resonances and Instabilities of Electrons in a Penning Trap — •Tristán Valenzuela Salazar, Debasish Biswas, Peter Paasche, and Günter Werth — Institut für Physik, Johannes Gutenberg Universität-Mainz. D-55099 Mainz. Germany
The motional spectrum of stored particles in an ideal Penning ion trap consists of three harmonic oscillations: The modified cyclotron frequency ωc′, the axial frequency ωz,and the magnetron frequency ωm. Imperfections lead to couplings between the eigenfrequencies. The frequency spectrum can be observed by excitation from an additional radio-frequency field. We have performed experiments on trapped electrons and observed many linear combinations of the eigenfrequencies. Excitation of ωz or 2ωz revealed a double structure of the resonances which could be ascribed to the excitation of the center of mass of the electron cloud and the non-correlated motion of the individual ions. Moreover we observed instabilities of the electron confinement at operating points of the trap when ωc′ or ωz are integer multiples of ωm. These observations are very similar to those made previously in Paul traps [1],[2]
[1] R. Alheit et al, Phys. Rev. A,56, 4023(1997) [2] R. Alheit et al, Int.J. Mass. Spectr. Ion Proc. 154, 155(1996)