Related Experiment Video
Updated: Jun 3, 2026

Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
Potential distribution and transmission characteristics in a curved quadrupole ion guide
Xiaoyu Zhou1, Caiqiao Xiong, Gaoping Xu
1Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing, China.
Abstract:
The potential distribution in the curved quadrupole is exactly characterized by the Laplace equation, and an approximate solution to the Laplace equation is calculated. We represent the Laplace equation under the coordinates named minimal rotation frame (MRF) and derive an expression on the hexapole and octopole superposition. Our conclusion is in agreement with the results by the numerical (SIMION) method. Based on the Poincare-Lighthill-Kuo (PLK) method reported in our previous work, the nonlinear effects of ion motion are investigated in detail. The frequency shift of ion motion can be well eliminated by coupling the hexapole component with a positive octopole component, and the transmission efficiency of ions is found to decrease dramatically with the increase of the ionic kinetic energy in the z-direction. Furthermore, the transmission characteristics of ions are discussed with regards to the phase-space theory. The results show that the centrifugally introduced axis shift is mainly responsible for the ion losses. A modified direct current (dc) voltage supply pattern is hence proposed to compensate for this effect.
Related Concept Videos
Mass Analyzers: Common Types
Electric Field Lines
The solution to this problem is to use electric field lines, which are not vectors but...
Continuous Charge Distributions
The electric charge can also be subjected to an analogical...
Properties of Electric Field Lines
For one, the electric field of a positive charge must originate from it. That is because its electric field points away from it. Moreover, since the magnitude of the field asymptotes to zero at infinity, the...
Gauss's Law: Cylindrical Symmetry
Induced Electric Dipoles
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...

