论文标题
使用参数激发从Paul陷阱中质量选择性去除离子
Mass-selective removal of ions from Paul traps using parametric excitation
论文作者
论文摘要
我们研究一种通过参数激发从PAUL陷阱中批量选择性去除离子的方法。这可以通过使用成对的相对电极对世俗频率$ω_ {\ text {sec}} $应用两倍的振荡电动四极电场来实现。虽然频率$ω_ {\ text {sec}} $在共振附近的激发仅导致振幅的线性增加，而激发持续时间，参数激发接近$ 2 \，ω_{\ text {sec}}} $导致振幅增加的结果。这可以有效地从陷阱中以适度的激发电压和狭窄的带宽从陷阱中去除离子，从而大大降低了离子与其他电荷与质量比的干扰。我们通过数值研究和比较两种方法的质量选择性。此外，我们通过实验表明，具有136和137个核的钡同位素可以从小离子晶体中去除并从陷阱中弹出，同时保持$^{138} \ text {ba}^{+} $ ions doppler冷却，对应于$Δm / m / m / m / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m = 1 / m。该方法可以广泛地应用于离子诱捕实验而没有重大修改的情况下，因为它仅需要调节离子陷阱的电势。
We study a method for mass-selective removal of ions from a Paul trap by parametric excitation. This can be achieved by applying an oscillating electric quadrupole field at twice the secular frequency $ω_{\text{sec}}$ using pairs of opposing electrodes. While excitation near the resonance with the frequency $ω_{\text{sec}}$ only leads to a linear increase of the amplitude with excitation duration, parametric excitation near $2\, ω_{\text{sec}}$ results in an exponential increase of the amplitude. This enables efficient removal of ions from the trap with modest excitation voltages and narrow bandwidth, therefore substantially reducing the disturbance of ions with other charge-to-mass ratios. We numerically study and compare the mass selectivity of the two methods. In addition, we experimentally show that the barium isotopes with 136 and 137 nucleons can be removed from small ion crystals and ejected out of the trap while keeping $^{138}\text{Ba}^{+}$ ions Doppler cooled, corresponding to a mass selectivity of better than $Δm / m = 1/138$. This method can be widely applied to ion trapping experiments without major modifications, since it only requires modulating the potential of the ion trap.
