Chinese Physics B
Comparison experiments of neon and helium buffer gases cooling in trapped 199 Hg + ions linear trap
Yu-Na Yang, Hao Liu, Yue-Hong He, Zhi-Hui Yang, Man Wang, Yi-He Chen, Lei She, Jiaomei Li
Abstract
The influences of different buffer gas, neon and helium, on Hg-199(+) clock transition are compared in trapped Hg-199(+) linear trap. By the technique of time domain's Ramsey separated oscillatory fields, the buffer gas pressure frequency shifts of Hg-199(+) clock transition are measured to be (df/dP(Ne)) (1/f) = 1.8 x 10(-8) Torr(-1) for neon and (df/dP(He)) (1/f) = 9.1 x 10 8 Torr(-1) for helium. Meanwhile, the line-width of Hg-199(+) clock transition spectrum with the buffer gas neon is narrower than that with helium at the same pressure. These experimental results show that neon is a more suitable buffer gas than helium in Hg-199(+) ions microwave frequency standards because of the Hg-199(+) clock transition is less sensitive to neon variations and the better cooling effect of neon. The optimum operating pressure for neon is found to be about 1.0 x 10(-5) Torr in our linear ion trap system.