https://doi.org/10.1140/epjad/i2005-06-185-x
ENAM 2004
Reaction cross-sections and reduced strong absorption radii of nuclei in the vicinity of closed shells N = 20 and N = 28
1
GANIL, BP 55027, F-14075, Caen Cedex 5, France
2
LPTN Faculty of Sciences, El Jadida BP 20, 24000, El Jadida, Morocco
3
LNS-INFN, 44 S. Sofia, 95129, Catania, Italy
4
Physics Division, Argonne National Laboratory, 9700 S. Cass Av., 60439, Argonne, IL, USA
5
Collège de France, 11 Place Marcelin Berthelot, F-75231, Paris Cedex 05, France
6
Nuclear Physics Institute ASCR, 25068, Rez, Czech Republic
7
Nuclear Physics Department, University of Surrey, GU27XH, Guilford, UK
8
Department of Physics, University of Liverpool, L69 7ZE, Liverpool, UK
9
CEA/DSM/DAPNIA/SPHN, CEN Saclay, F-91191, Gif-sur Yvette, France
10
LPC, ISMRA and University of Caen, F-6704, Caen, France
11
Department of Physics and Astronomy, The Open University, MK6 2HL, Walton Hall, Milton Keynes, UK
12
University of S ao Paulo IFUSP, C.P. 66318, 05315-970, S ao Paulo, Brazil
13
FLNR, JINR Dubna, P.O. Box 79, 101000, Moscow, Russia
* e-mail: villari@ganil.fr
Received:
10
January
2005
Accepted:
3
May
2005
Published online:
14
July
2005
Energy integrated reaction cross-section measurements of around sixty neutron-rich nuclei covering the region of closed shells N = 20 and N = 28 were performed at intermediate energy (30-65 A . MeV) using direct method. In this experiment, silicon detectors were used as active targets. The reduced strong absorption radii, r 0 2, for 19 new nuclei (27F, 27,30Ne, 33Na, 28, 34-35Mg, 36-38Al, 38-40Si, 41-42P, 42-44S and 45Cl) are deduced for the first time. An additional 60 radii, also measured in this experiment, are compared to results from literature. A new quadratic parametrization is proposed for the nuclear radius as a function of the isospin in the region of closed shells N = 8 and N = 28. According to this parametrization, the skin effect is well reproduced and anomalous behaviour on the radii are observed in 23N, 29Ne, 33Na, 35Mg, 44S, 45Cl and 45Ar nuclei.
PACS: 21.10.Gv Mass and neutron distributions – / 25.60.Dz Interaction and reaction cross-sections –
© Società Italiana di Fisica and Springer-Verlag, 2005