1 Experimental Determination of the Stable Boundary for a Cylindrical Ion Trap Andrew Alexander, Dr. Victor Kwong*, Brad Clarke, James Benevente UNLV Summer REU Program, Las Vegas, Nevada August 9, 2010

2 Introduction  Ion Traps: first designed with hyperbolic electrodes Equations of motion – exact analytic solution Difficult fabrication process  Cylindrical ion trap Easily constructed and functional alternative Theoretical model remains elusive.

3 Objective  Ions near center of trap “see” approx. hyperbolic potentials Good starting point Exact trapping parameters must be determined experimentally  Goals: Determine stable boundary for cylindrical design Compare findings: simulated results & hyperbolic electrode theory

4 System Components

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10 Trap Design Basics  Ring electrode: AC potential (V0) & DC potential offset (U0) end cap electrodes ring electrodes

11 Theory – Hyperbolic  Ion equation of motion Form of Mathieu differential equation: & – linearly related - V 0 and U 0

12 Simulation - Cylindrical  Ion equation of motion No simple solution  Turn to simulation program: SimIon Numerically determine ion trajectory  & defined the same – comparison

Methods Experiment 1Experiment 2 (Delta U 0 )  Ions created and stored with au near boundary  Ions storage times: 345 & 690 ms  Ions created and cooled – 700 ms Ideal trapping parameters  U 0 brought near boundary  2 ms storage time near boundary Basic Process  Ion signal scanned as a function of Uo  Boundary approx. where signal is lost

14 Global Comparison of Results

15 Conclusion  Creation of ions near the boundary adversely affects ion population  Trap design appear to “leak” ions over time  Delta U 0 approach minimizes these complications

16 Acknowledgments  Dr. Victor Kwong  Brad Clarke  James Benevente  Financial support from NSF REU program DMR is gratefully acknowledged. 16