Determination of the geometric parameters and of a linear Paul trap

An effective method for determining the geometric parameters of a linear Paul trap is provided and carried out in this paper. The method is based on exciting the secular motion of laser-cooled Ca+ ions in a linear Paul trap with varied trapping potentials. Taking advantage of the segmented structure of the linear Paul trap, both the axial and the radial geometric parameters are obtained by applying external excitation fields to the trapping electrodes directly. The axial geometric parameter of our linear Paul trap is determined to be 0.374(3), and, for the first time, the radial geometric parameter is determined to be 0.928(2).