학술논문
Accessing tens-to-hundreds femtoseconds nuclear state lifetimes with low-energy binary heavy-ion reactions
Document Type
Working Paper
Author
Ciemala, M.; Ziliani, S.; Crespi, F. C. L.; Leoni, S.; Fornal, B.; Maj, A.; Bednarczyk, P.; Benzoni, G.; Bracco, A.; Boiano, C.; Bottoni, S.; Brambilla, S.; Bast, M.; Beckers, M.; Braunroth, T.; Camera, F.; Cieplicka-Orynczak, N.; Clement, E.; Coelli, S.; Dorvaux, O.; Erturk, S.; De France, G.; Fransen, C.; Goldkuhle, A.; Grebosz, J.; Harakeh, M. N.; Iskra, L. W.; Jacquot, B.; Karpov, A.; Kicinska-Habior, M.; Kim, Y. -H.; Kmiecik, M.; Lemasson, A.; Lenzi, S. M.; Lewitowicz, M.; Li, H.; Matea, I.; Mazurek, K.; Michelagnoli, C.; Matejska-Minda, M.; Million, B.; Muller-Gatermann, C.; Nanal, V.; Napiorkowski, P.; Napoli, D. R.; Palit, R.; Rejmund, M.; Schmitt, Ch.; Stanoiu, M.; Stefan, I.; Vardaci, E.; Wasilewska, B.; Wieland, O.; Zieblinski, M.; Zielinska, M.
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Subject
Language
Abstract
A novel Monte Carlo technique has been developed to determine lifetimes of excited states in the tens-to-hundreds femtoseconds range. The method is applied to low-energy heavy-ion binary reactions populating nuclei with complex velocity distributions. Its relevance is demonstrated in connection with the $^{18}$O(7.0 MeV/u) + $^{181}$Ta experiment, performed at GANIL with the AGATA+VAMOS+PARIS setup, to study neutron-rich O, C, N, ... nuclei. Excited states in $^{17}$O and $^{19}$O, with known lifetimes, are used to validate the method over the $\sim$20-400 fs 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, at the basis of the detailed analysis of $\gamma$-ray lineshape and resulting state lifetime determination. The technique is anticipated to be an important tool for lifetime investigations in exotic neutron-rich nuclei, produced with intense ISOL-type beams.