Sympathetic cooling of Rb+ ions by cold Rb atoms is studied in an ion-neutral hybrid trap. The effect of a linear Paul trap (LPT) parameter q1,2 on the sympathetic cooling is studied by measuring the changes in ion number Ni and temperature Ti after interaction with cold atoms. The sympathetic cooling effect is observed with 0.3 ≤ |q1,2| ≤ 0.8. At the |q1,2| value of 0.32, ions are cooled from initial (2 010±380) K to (325±35) K and the lifetime of ions is extended from 7 s to 15 s via sympathetic cooling. These findings are very useful for cooling of atomic and molecular ions, especially for the ions without available optical channels.
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