Novel radio-frequency quadrupole ion trap with spherical geometry

•A novel radio-frequency quadrupole ion trap with spherical geometry is introduced.•The octupole component of the electric field inside our trap is eliminated.•Electric quadrupole is the dominant term of the electric field inside our trap.•Three stability regions of our trap coincide well with those of Paul trap.•Our spherical ion trap is an appropriate choice for miniaturization.

Confinement of single ions in a novel radio-frequency (RF) quadrupole ion trap with spherical shape is investigated. An optimization of this spherical ion trap (SIT) is carried out in order to suppress its nonlinearity substantially by eliminating the electric octupole moment. Hence, a trapping potential and consequently an electric field very similar to the ideal quadrupole ion trap (QIT) are obtained. Afterwards, three stability regions for the optimized SIT are numerically computed. The regions coincide well with those reported in the literature for the ideal QIT. The reason is attributed to the zero electric octupole moment of our proposed trap. The simple geometry of our optimized SIT and relative ease of fabrication along with its increased trapping volume in comparison with the conventional hyperbolic quadrupole ion trap, make it an appropriate choice for miniaturization.

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