Citation
Abstract
This article presents the exact potential corresponding to confining fields inside a linear rf quadrupole particle trap of finite length. The analytic expression for the trapping potential is derived by introducing a linear trap employing a relatively simple cylindrical geometry and solving Laplace’s equation for the trap electrodes. The finite length of linear traps results in field distortion near the trap ends. An exact analytic determination of the fields is useful because the profile of the trapped ion cloud is highly dependent on the fields confining it. It is shown that near the ends of the trap, the effective potential arising from the rf fields acts to propel particles out of the trap, and further, that the addition of a dc bias generates an inhomogeneous field in the trap that influences the particles both perpendicularly to and along the trap’s long axis.
Details
- Volume
- 42-101
- Published
- May 15, 1990
- Pages
- 51–60
- File Size
- 481.7 KB