Cooling effect of different buffer gas of trapped mercury ions in a linear ion trap

Abstract

Abstract:

Buffer gas cooling is the most effective and practical method to cool ions in ion trap. And the kind and the quantity of buffer gas are the key technologies in mercury ion microwave frequency standard experiments. We study buffer gas made of Helium, Neon or Argon to cool trapped Mercury ions (199Hg+) in a linear ion trap by introducing a resistance term in Mathieu’s equation. We find that the decay time of motion of 199Hg+ in Argon gas is the shortest. We get that the frequency shift of the clock transition (40.5 GHz) is minimum when the pressure of Helium is 10-5 Torr or when the pressure of Neon gas is 2.4×10-5 Torr. Neon is the most suitable buffer gas among Helium, Neon and Argon, considering the decay time-constant of motion of 199Hg+ in buffer gases and 199Hg+ clock transition shift’s sensitivity to the change of the pressure of buffer gas.

Key words: spectroscopy, trapped Hg+ ions, buffer gas cooling, second-order Doppler shift, collision shift

CLC Number:

O561.5

YANG Yu-na, LIU Hao, HE Yue-hong, CHEN Yi-he, SHE Lei, LI Jiao-mei. Cooling effect of different buffer gas of trapped mercury ions in a linear ion trap[J]. J4, 2012, 29(2): 129-134.

References

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