Effect of cascading of higher-lying states on a delayed 1 s-2 p transition after beam-foil excitation of 56 MeV hydrogen-like oxygen and fluorine

The delayed fluorescence of the soft X-ray (1 s-2 p) transition was observed for H-like ions (O7+ and F8+) between 1.3 ns and 20 ns decay time after beam-foil excitation. The delayed X-ray fluorescence was found to decay with a tΔ power law time dependence. The non-exponential decay is attributed to cascading through higher lying states. We found that Δ0=1.40±0.08 and ΔF=1.44±0.02 for H-like oxygen and fluorine, respectively. Present results are in fair agreement with the previously reported exponent, Δ0=1.5, measured over 3 ns after excitation. © 1981 Springer-Verlag.