Beam-foil lifetime study of then=3 complex in al-like Ti9+

Abstract

The beam-foil spectrum obtained using a beam of Ti3+ ions of energy 10 MeV has been studied over the wavelength range from 14 nm to 80 nm. New assignments are suggested for 18 levels belonging to the levels of the 3p3, 3s 3p 3d and 3s2 4p configurations. The lifetimes of these levels, as determined from conventional multi-exponential curve fitting of their intensity decay curves, are typically about 30% longer than is forecast by theory. The same decay curves have also been used to represent the effect of cascade repopulation on the decay curves obtained for the resonance doublet levels of the 3s 3p2 and 3s2 3d configurations. A discussion is given of the possible techniques for cascade correction in beam-foil lifetime measurements, and of the inclusion of a window function to represent the vignetting effect close to the foil. Lifetimes obtained using these techniques for the 3s2 3d levels (38±6 ps for J=3/2, 36±5 ps for J=5/2), and the 3s3p22S level (99±6 ps),2P levels (60±15 ps for J=1/2, 50±15 ps for J=3/2) and2D levels (820±30 ps for j=3/2, 870±40 ps for J=5/2) are in good agreement with theoretical predictions.