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Instability Heating of Sympathetically-Cooled Ions in a Linear Paul Trap

T. J. Harmon·N. Moazzen-Ahmadi·R. I. Thompson
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Abstract

Sympathetic laser cooling of ions stored within a linear-geometry, radio frequency, electric-quadrupole trap has been investigated using computational and theoretical techniques. The simulation, which allows 5 sample ions to interact with 35 laser-cooled atomic ions, revealed an instability heating mechanism, which can prevent ions below a certain critical mass from being sympathetically cooled. This critical mass can however be varied by changing the trapping field parameters thus allowing ions with a very large range of masses to be sympathetically cooled using a single ion species. A theoretical explanation of this instability heating mechanism is presented which predicts that the cooling-heating boundary in trapping parameter space is a line of constant $q_u$ (ion trap stability coefficient), a result supported by the computational results. The threshold value of $q_u$ depends on the masses of the interacting ions. A functional form of this dependence is given.

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T. J. Harmon, N. Moazzen-Ahmadi, R. I. Thompson. 2002-08-19. Instability Heating of Sympathetically-Cooled Ions in a Linear Paul Trap. https://doi.org/10.1103/physreva.67.013415

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