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Publication

Accessing Tens-to-Hundreds Femotoseconds Nuclear State Lifetimes with Low-Energy Binary Heavy-Ion Reactions

Authors

Ciemala, M.; Ziliani, S.; Crespi, F.; Leoni, S.; Fornal, B.; Maj, A.; Bednarczyk, P.; Benzoni, G.; Bracco, A.; Boiano, C.; Mller-Gatermann, C.

Abstract

A novel Monte Carlo technique has been developed to determine lifetimes of excited states in the tens-to-hundreds femtoseconds range in products of low-energy heavy-ion binary reactions, with complex velocity distributions. The method is based on a detailed study of Doppler-broadened gamma-ray lineshapes. Its relevance is demonstrated in connection with the 18O(7.0MeV/u)+181Ta experiment, performed at GANIL with the AGATA+VAMOS+PARIS setup, to study neutron-rich O, C, N, … nuclei. Excited states in O-17 and O-19, with known lifetimes, are used to validate the method over the similar to 20-400fs lifetime-sensitivity range. Emphasis is given to the unprecedented position resolution provided by gamma-tracking arrays, which turns out to be essential for reaching the required accuracy in Doppler-shift correction. The technique is anticipated to be an important tool for lifetime investigations in exotic neutron-rich nuclei, produced with intense ISOL-type beams.