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Probing the structure of neutron-rich N=12-16 F,O,Ne isotopes using deep-inelastic collisions. G. Benzoni. G. Benzoni, A. Bracco, S. Leoni, N.Blasi, F. Camera, F. Crespi, B. Million, O. Wieland, Università degli Studi and INFN sezione di Milano - PowerPoint PPT Presentation
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Probing the structure of neutron-rich N=12-16 F,O,Ne isotopes using deep-inelastic collisions
G. BenzoniG. Benzoni, A. Bracco, S. Leoni, N.Blasi, F. Camera, F. Crespi, B. Million, O. Wieland,
Università degli Studi and INFN sezione di MilanoG. De Angelis, A. Gadea-Raga, D. Napoli, A. Stefanini, L. Corradi, E. Fioretto, J.J. Valiente-Dobon, N. Marginean
LNL, Laboratori Nazionali di LegnaroS. Lunardi, S.M. Lenzi,D. Bazzacco, E. Farnea, G. Montagnoli, C. Ur, S.Beghini, F.Scarlassara,
Università and INFN sezione di PadovaM.Trotta,
INFN NapoliG. Lobianco, C. Petrache,
Università di Camerino and INFN PerugiaA.Zucchiatti, M.Castoldi,
INFN sezione di GenovaA. Maj, M. Kmiecik, K. Mazurek, J. Styczen, W. Meczynski, K. Zuber,
The Niewodniczanski Institute, KrakowF.Azaiez, F. Ibrahim, D. Verrey, M. Stanoiu, Ch. Bourgeois,
Institut de Physique Nucleaire, OrsayG. DuLove, D. Curien, Ch. Beck,
IRES StrasbourgH. Savajols, M. Rejmund, A. Navin, G. DeFrance,
GANIL, CaenN. Redon, M. Meryer, O. Stezowski
IPN, Lyon
HHe
LiBeBC
NO
FNe
NaMg
31F24O
H.Sakurai et al., Phys. Lett. 448B (1999) 180
M.Fauerbach et al., Phys.Rev.C53 (1996) 647
Search for the n-dripline…
• location of n drip line between F and O is not understood N=16 for O and N=22 for F• role played by 1 and 2 p outside shell closure Z=8
Test of accurate shell model calculations in light nuclei
24O
23O
Population of n-rich Ne, F and O nuclei
CNO
FNe
NaMg
31F24O
Information on reaction
dynamics in light nuclei
Aim of the project:
Outline : current status of • O isotopes • F isotopes
• Ne isotopes
26Mg @ 130 MeV + 208Pb/U target
20OMSU exp
Oxygen isotopes
E. Tryggestad et al., Phys. Lett. B541, 52-58(2002).
Experimental info for N = 12 and 14
1710
4852
3199
3710
± 9
0
expSM M. Stanoiu et al., Phys. Rev. C69, 034312 (2004).
Need to firmly establish these transitions
GANIL exp
Oxygen isotopes
Experimental info for N = 15 and 16
Search for first excited state Recoil shadow technique with CLARA
No evidence for excited states…
M. Stanoiu et al., Phys. Rev. C69, 034312 (2004).
GANIL exp
A. Brown et al., http://www.nscl.msu.edu/~brown
400 = 8.8 ns ?
Sn = 2.7 MeVSn = 3.7(4) MeV
M.Belleguic et al. NPA682(2001)136c
F isotopes: N = 16
25F
26F
27FZ.Elekes et al. PLB599(2004)17
Need to firmly establish these transitions
GANIL expCourtesy of F.Azaiez
Ne isotopes : Isle of inversion and n gap evolution from N=20 to N=14 (16)
Proposed experiment @ Prisma + Clara
• 26Mg @ 130 MeV + 208Pb/U target• 18O @ 110 MeV + 208Pb target
Beam time request: 7 days of 26MgWith possibly 2 days of 18O
Future proposal: 22Ne @ 125 MeV + 208Pb target (LOI)
More details on the proposal
• grazing angle: 80° angle of Prisma• Prisma efficiency @ grazing angle: 3-5 %• 60-70% efficiency at focal plane cfr. 24Mg+24Mg experiment (F.Hass)
• 24 to 25 Clovers setup Clara• efficiency ~ 3 %• Peak/Total ~ 50%• Position = 104°– 156°• FWHM ~ 10 keV @ 1.3 MeV and v/c = 10%
30000 p- coincidences in weakest channels in 7 days( ~1000 p-coincidences
E*1
E*2
Measurement of the gamma decay from pygmy resonance using netron transfer reaction at 15 MeV/u(d,p) in inverse kinematics
For more neutron rich nuclei this yield is expected to be much larger
A. Voinov et al, PRC (2002)
Gamma-ray particle coincidence , difference techniqueobtain also the level density, important information for calculationsof reaction rates in the r-process
Before After
Courtesy of A.Gadea
Coaxial HPGe + BGO in add back
B.Million et al NIM A452(2000)422
Euroball Cluster in Add Back (no BGO)
HPGe for High Energy gamma rays
Complementary to in-beam spectroscopy with fragmentation reactions
• high lying states in Ne, F, and O isotopes• n-odd isotopes in particular…known less accurately• Information on reaction mechanism with light n-rich nuclei• complete distributions of production yields in order to study the N/Z equilibration process in deep inelastic reactions induced by neutron-rich beams
24Ne @ 114 MeV + Pb or U target
22Ne @ 125 MeV + 208Pb target
Vamos+Exogam
Proposed joint experiments:
Prisma + Clara
Stable and radioactive beams to study similar nuclei comparison of cross sections and reaction mechnisms
Ibeam ~106