0000000000809631
AUTHOR
Fernande Vedel
Observation of instabilities in a Paul trap with higher-order anharmonicities
Systematic measurements of the relative ion number stored in a Paul trap within the stability diagram given by the solution of the equation of motion reveal many lines, where only few or no ions can be confined. The observations can be explained by the presence of perturbations from higher-order components in the trapping potential, which is a quadrupole potential in the ideal case. The resonances follow the equation (nr/2)βr + (nr/2)βz = 1,nr +nz =N, where 2N is the order of the perturbation,nr,nz are integer andβr,βz are stability parameters of the trap. The experiments were performed on H+ and H2+ ions, which are detected after a storage time of 0.3 s by ejection from the trap.
Experimental lifetime of the metastable 5D 3/2 state in Ba+
A discrepancy exists between theoretical and experimental lifetimes of the metastable 5D3/2 state in Ba+. In order to redertermine that lifetime, we probe the population of the metastable 5D3/2 state of a Ba+ ion cloud stored in a Paul ion trap in the presence of He buffer gas as the function of time delay after pulsed laser excitation of this state. The measured decay rates at different buffer gas pressures are extrapolated to zero pressure and we obtain a radiative decay time of 48.0±5.9 s. This is not in agreement with theoretical predictions of about 80 s, but reduces the discrepancy from a previously reportet experimental value of 17.5 s. If the possibility of finestructure mixing to a…
Lifetime and collisional depopulation of the metastable 5D 3/2-state of Yb+
The lifetime and collisional depopulation rates of the metastable 5D 3/2 state of Yb+ have been determined in a radiofrequency ion trap by observation of the fluorescence count rate after ion excitation by a short laser pulse. From measurements using He, N2 and H2 as buffer gases between 10−8 and 10−6 mbar pressure and linear extrapolation to zero pressure we obtain a lifetime of τ=52.15±1.00 ms and rate constants ofR(H2)=(1.02±0.10)×10−9 cm3/s andR(N2)=(1.78±0.19)×10−10 cm3/s. The lifetime is in fair agreement with a calculated value of 74 ms.