Paul阱中离子云囚禁时间的分析  

Analysis of the Traping Time of the Ion-cloud Stored in a Paul Trap

作　　者：张志飞[1] 罗学立[1] 李交美[1] 陈永泰[1] 朱熙文[1] 高克林[1] 

机构地区：[1]中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室

出　　处：《Chinese Journal of Chemical Physics》1998年第5期399-403,共5页化学物理学报（英文）

基　　金：国家自然科学基金

摘　　要：结合缓冲气体Ｈｅ对囚禁离子云Ｎ＋２的冷却实验结果，给出了在综合考虑射频加热和缓冲气体冷却效应情形下，阱中囚禁离子数随时间变化的理论模型，讨论了Ｐａｕｌ阱中的加热系数。γ、离子云温度Ｔ、随机力涨落Ｄ等参数对囚禁时间的影响。We observed variations of the storage time of ions N+2 trapped in an RF trap when the buffer gas He presented. After phenomenologically considering the RF heating the RF heating as an additive contestant to the buffer gas damping, we calculated the storage time of trapped ions in terms of the mean first passage time of the Brownian motion of their energy in the pseudopotential well of a Paul trap. From the parameters fitted out from experimental data based on this generalized model, one can see that the storage time increases as the daming γ,the fluctuation strength D and the initial temperature T decrease, which interprets quantitatively the experimental results the variations of the storage time when N+2 were cooled by buffer gas He. It also shows that the damping coefficient γis always positive whether buffer gas isinput or not, which suggests that the RF heating effect is dominated in our experiments thoughthe γ decreases after buffer gas is input. On the other hand, if one can evaluate the damping coefficient γ,fluctuation strength D and the initial energy distribution of the ion cloud, it ispossible to know the concrete value of the storage time and the total ion number based on thismodel. These conclusions will benefit to understand the dynamic process of the buffer gas cooling and are of importance to related fundamental and applied researches.

关 键 词：PAUL阱 缓冲气体 囚禁时间 氮离子 离子云 

分 类 号：O613.61[理学—无机化学]