Chemistry and Biochemistry

Two Plate Linear Ion Trap


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The Planar linear ion trap (PLIT) is a novel miniaturized mass analyzer, which consists of metal electrodes that are lithographically patterned onto two opposing planar ceramic substrates.  An electric field for ion trapping is formed between the two ceramic plates by applying specific voltages to the electrode pattern. This technique is relatively immune to problems with surface roughness, machining complexity, electrode misalignment, and precision of electrode shape.




One critical purpose in the research is to increase the capability of PLIT with reduced plate spacing in order to make the trap as small as possible. The other purpose is to design the configuration of the electrodes on the plates, and thus achieve good resolution by optimizing the distribution of the electric field between two plates.

Another part of our research is studying the effect of misalignment on resolution. Linear ion trap can effectively improve the trapping capacitance at the same trapping size as a traditional cylindrical ion trap, but is unfortunately believed to be more sensitive to displacements among electrodes. We are researching to find out whether misalignment is a big issue on the resolution and intensity of linear ion trap.

The Linear ion trap has a total of six degrees of freedom; pitch, yaw, roll, and x, y and z-displacement, and according to simulation and calculation, pitch is believed to have the biggest effect on resolution. 







To experiment with the pitch, a solenoid is attached to one of the plates and we can vary the pitch by select increments. In the preliminary experiments, the resolution does change some but doesn’t change as much as we expected from our simulation. There is always one optimal point in the pitch to achieve the highest resolution for each of the different plate separations. We are now working on further improving the resolution and exploring the effects of the other degrees of freedom.