Doppler-shift lifetime measurements of levels in 45Sc and in 46Ti

Abstract

The lifetimes of 15 levels in 45Sc up to 2.8 MeV and of 12 levels in 46Ti have been measured by the Doppler-shift attenuation method, using the reactions 45Sc(p, p'γ) 45Sc and 45Sc(p, γ) 46Ti. A two-target arrangement for the quasi-simultaneous observation of γ-rays at a forward and a backward angle was used in the measurements. For the extraction of lifetimes from the shifts observed in the (p, p'γ) singles γ-spectra, F( τ) curves averaged over all initial recoil velocities were employed. A correction factor ƒ = 0.9 to the theoretical stopping power, obtained by comparing the lifetimes of four levels in 45Sc with results from resonance fluorescence measurements, was used in the lifetime analysis for both nuclei. The new lifetime results for 46Ti help to clarify discrepancies in previous results.