Correcting symmetry imperfections in linear multipole traps

J. Pedregosa-Gutierrez (1) , C. Champenois (1) , M. Houssin (1) , M.R. Kamsap , M. Knoop (1)

1 PIIM - Physique des interactions ioniques et moléculaires

Multipole radio-frequency traps offer new possibilities for tailoring well-defined individual-ion crystals and in particular the potential to create 2D-structures. However, multipole traps have also been shown to be very sensitive to geometrical misalignment of the trap rods, leading to additional local trapping minima. The present work proposes a method to correct non-ideal potentials, by modifying the applied radio-frequency amplitudes for each trap rod. This approach is discussed for the octupole trap, leading to the restitution of the ideal Mexican-Hat-like pseudo-potential, expected in multipole traps. The goodness of the compensation method is quantified in terms of the choice of the diagnosis area, the residual trapping potential variations, the required adaptation of the applied radio-frequency voltage amplitudes, and the impact on the trapped ion structures. Experimental implementation is also discussed, in order to propose a diagnostic method with respect to the resolution and stability of the trap drive. Using the proposed compensation technique, we discuss the feasibility of generating a homogeneous ion ring crystal, which is a measure of quality for the obtained potential well.

Domaines: Physique Atomique [physics.atom-ph]

J. Pedregosa-Gutierrez, C. Champenois, M. Houssin, M.R. Kamsap, M. Knoop. Correcting symmetry imperfections in linear multipole traps. 2018. ⟨hal-01851556v1⟩