Pre-equilibrium Emission and α-clustering in Nuclei

11th International Spring Seminar on Nuclear Physics: Shell Model and Nuclear Structure – achievements of the past two decades

Gramegna, F.^1 ; Fabris, D.^2 ; Marchi, T.^1 ; Degerlier, M.^3 ; Fotina, O.V.^4,5 ; Kravchuk, V.L.^6 ; D'Agostino, M.^7 ; Morelli, L.^7 ; Appannababu, S.^1 ; Baiocco, G.^7 ; Barlini, S.^8 ; Bini, M.^8 ; Brondi, A.^9 ; Bruno, M.^7 ; Casini, G.^8 ; Cinausero, M.^1 ; Gelli, N.^8 ; Moro, R.^9 ; Olmi, A.^8 ; Pasquali, G.^8 ; Piantelli, S.^8 ; Poggi, G.^8 ; Valdrè, S.^8 ; Vardaci, E.^9

INFN-Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy^1

INFN Sezione di Padova, Padova, Italy^2

Nevsehir Haci Bektas University, Science and Art Faculty, Physics Dep., Nevsehir, Turkey^3

Physical Department, Lomonosov Moscow State University, Moscow, Russia^4

Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia^5

National Research Center, Kurchatov Institute, Moscow, Russia^6

Dipartimento di Fisica, Università di Bologna, INFN Sezione di Bologna, Bologna, Italy^7

Dipartimento di Fisica, Università di Firenze, INFN Sezione di Firenze, Firenze, Italy^8

Dipartimento di Fisica, Università di Napoli, INFN Sezione di Napoli, Napoli, Italy^9

关键词: Cluster projectiles;    Evaporation residues;    Experimental campaign;    Experimental evidence;    Light charged particles;    Molecular configurations;    Particle separation;    Theoretical modeling;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/580/1/012011/pdf
DOI  :  10.1088/1742-6596/580/1/012011

来源: IOP

【 摘 要 】

The study of nuclear states built on clusters bound by valence neutrons in their molecular configurations is a field of large interest, which is being renewed by the availability of exotic beams: clustering is, in fact, predicted to become very important at the drip-line, where weakly bound systems will prevail. Although for light nuclei at an excitation energy close to the particle separation value there are experimental evidences of such structure effects, this is still not the case for heavier nuclear systems. Many attempts have been done using preformation alpha clustering models, but there is still a lack of experimental data capable to give a direct feedback. In particular, searching for alpha clustering effects in medium mass systems is still a challenge, which can give new hints in this subject. In the past we have studied the reactions 250, 192 and 130 MeV16O +116Sn, observing a significant increase in the fast emitted α-particle yield. This effect was ascribed to the presence of preformed a-clusters in the16O projectile nucleus. In order to investigate these aspects, in a model independent way, a new experimental campaign has been performed with the GARFIELD + RCo set up, to compare results from two different reactions: a double magic a-cluster (16O) and a non-magic α-cluster projectile (19F) at the same beam velocity (16AMeV) have been chosen, impinging respectively on65Cu and62Ni targets, thus leading to the same81Rb∗ compound nucleus. The angular distributions and the light charged particles emission spectra in coincidence with evaporation residues have been measured and analyzed. The preliminary results of the data analysis and the main features of the theoretical model used for their interpretation are presented.