Excitation Energy of the Fourth Excited State in 18F

Abstract

The excitation energy of the Jπ = 5+, fourth excited state in 18F has been determined to be Ex = 1119.0 ± 0.6 keV from a measurement of the energy of the γ-ray transition to the 937 keV, first excited state. This new excitation energy removes the discrepancies in the excitation energy of resonant states based on γ-ray decay schemes involving this state. The mean lifetime has been determined to be τ(1119) = 218 ± 8 ns by a delayed coincidence measurement between the γ rays populating and deexciting this state.