Quadrupole Ion Trap using ElecNet

Ion trap technology is a modern invention designed to manipulate atoms for applications in engineering and sciences such as mass spectrometry and particle accelerators.

Using ElecNet, Infolytica's electric field simulation software, it is possible to design such devices. The Trajectory Evaluator can be used to track the trajectories of charged particles in this device. In this example, the trajectory of a charged particle entering a quadrupole ion trap is simulated. The results are presented below.

The image to the left shows a slanted top view of a quadrupole ion trap with the top electrode removed. The curved faces of the side electrode as well as that of the bottom electrode are clearly visible.

Results

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To the right is a schematic representation of the electrostatic solution and particle trajectory expected in a quadrupole ion trap. The device has been created using ElecNet and the appropriate components, i.e., the top, bottom and the side electrodes have been defined and initialized to be at 0, 0 and 200 V, respectively.

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The model has been solved and a 2D slice taken along the axis of symmetry of the electrostatic simulation of this device with the magnitude and equipotential lines marked. The results qualitatively prove that the basic design of the trap is accurate. Using both ElecNet and Trajectory Evaluator, the behaviour of a unit electric charge (of value -1.6e-29) placed at the center of the ion trap is simulated while the side electrode is subjected to a frequency of 100 Hz. The dynamics of this charge is tracked as a function of time. The results are shown below.

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x position of test charge versus time

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y position of test charge versus time

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x component of charged particle velocity versus time

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x component of charge particle acceleration versus time

A simple, multidimensional application of ElecNet and Infolytica’s multi-physics capability using the Trajectory Evaluator has been demonstrated here using the example of a quadrupole ion trap. The results obtained are in good agreement with those from literature. In general, ElecNet may be used to consider static and transient solutions in both two and three dimensions.