ions has been studied in ESR experiments at GSI. The experiments have been carried out in two modes. One of them was to store a large number of parent ions and to monitor continuously the number of parent and daughter ions. The other way was to inject on average 2 parent ions. In this way the decay times of each ion could be accurately determined. While the decay curves, measured with many parent ions, follow the expected exponential behavior [2, 3], a modulated in time exponential decay [1] has been observed in single-ion experiments. In this report we show that these results are consistent. Let us assume that the number of stored parent ions at time t, NM (t), decreases at a rate: dNM (t) dt where the total decay rate ˜ λ is the sum: = − ˜ λ · NM (t) (1) ˜λ = λβ + λEC(1 + a cos(ωt + φ)) + λloss (2) The solution of equation (1) is: NM (t) = NM (0) · exp [−λt(1 + aλEC λ · sin(ωt+φ) ωt)] (3) where λ = λβ + λEC + λloss. In the case of nonmodulated EC-decay rate (a = 0) we find the usual solution: N 0 M (t) = NM (0) · exp [−λt] The number of stored parent ions NM (t) and N 0 M (t) as well as the diference N 0 M (t) − NM (t) are plotted in Fig. 1 using the experimental parameters as the example of 142Pm [1, 3]. We note that the relative change has an upper bound

Year: 2012

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