Nuclear resonance fluorescence in121Sb

Using γ quanta from a⁵⁶Co source, resonance fluorescence from a 3,452 keV level in¹²¹Sb was observed. Four deexciting γ transitions were identified. The profile of the γ emission line, investigated by means of a high speed centrifuge, yields with a novel variety of Doppler shift analysis a lifetime of τ_4,298=(110±50)fs for the γ emitting 4,298 keV level in⁵⁶Fe. The lifetime of the 3,452 keV level was determined to be τ _3,452 =(200±100)fs.