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Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target C. Monrozeau (Ph. D), E. Khan, Y. Blumenfeld
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Motivations: exotic modes ? Few measurements on GR in unstable nuclei IVGDR GQR and GMR soft modes are predicted ! Terasaki et al, Phys. Rev. C71 (2006) 34310
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Motivations: equation of state GMR breathing mode density variation around 0 (few %) Nuclear equation of state E ISGMR along an isotopic chain (unstable nuclei) D.T.Khoa et al. Nucl. Phys. A602 (1996) 98 evolution of incompressibility with asymmetry Neutron stars and neutron excess determination of K (symmetry energy term) : density
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D.H. Younblood et al, Phys. Rev. Lett 76, 1429 (1996) 58 Ni ’ =240 MeV Inelastic scattering : (d,d’) ’ @ E 25 A.MeV GQR GMR GR in 58 Ni : analysis mixing 0 + and 2 + Experimental probes for isoscalar giant resonances
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reverse kinematics unstable nuclei good detection efficiency thick target low intensity beam large solid angular coverage low energy threshold thin target ISGMR in unstable nuclei Time and Charge Projection Chamber Active target = target + detector deuterium gas : 1,6 mg/cm 2 (6,3 mg/cm 2 CD2 ) deuteron kinematics 56 Ni(d,d’) @ 50 MeV/A cathod Frisch grid beam amplification wires pads (cathod) detection zone active zone
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MAYA 56 Ni @ 50 MeV/A 5.10 4 pps July 2005, GANIL SISSI beam Experimental setup Au foil Drift chamber Ionisation chamber Moving flap Si wall CsI wall Diamond 56 Ni (5.10 4 pps) 50 A.MeV + contaminants
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Results d breakup 56 Ni excitation energy spectrum recoiling d kinematics
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Analysis with gaussian fit E* (MeV) Counts/MeV Reaction : DWBA with double folding using HF and RPA 56 Ni gs and transition densities
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Multipole Decomposition Analysis
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Isoscalar GMR and GQR measured in the 56 Ni unstable nucleus Use of MAYA active target with d gas 16h of 10 4 pps beam Results compatible with the 58 Ni (stable) data The method works ! Improvements : identification & d breakup, reaction model Next : neutron rich Ni isotopes, 132 Sn ACTAR active target Summary & outlooks first (p,p’) experiment in inverse kinematics ! G. Kraus et al. Phys Rev. Lett. 73 (1994) 1773
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Collaboration C.Monrozeau 1, E.Khan 1, Y. Blumenfeld 1, W. Mittig 5, D.Beaumel 1, M.Caamaño 2,D.Cortina- Gil 2, C-E.Demonchy 3, N.Frascaria 1, U.Garg 4, M.Gelin 5, A.Gillibert 6, D.Gupta 1, N. Keeley 6, F.Maréchal 7, A.Obertelli 6, P.Roussel-Chomaz 5, J-A.Scarpaci 1 1 Institut de Physique Nucléaire (IN2P3/CNRS), 91406 Orsay Cedex, France 2 Univ. Santiago de Compostela, E-15706 Santiago de Compostela, Spain 3 Univ. of Liverpool, Dep. of Physics, Olivier Lodge Lab., Liverpool L69 7ZE, U.K. 4 Univ. of Notre-Dame, Dep. of Physics, Notre Dame, IN 46556 USA 5 GANIL (DSM/CEA, IN2P3/CNRS), BP 5027, 14076 Caen Cedex 5, France 6 CEA/DSM/DAPNIA/SPhN, Saclay, 91191 Gif-sur-Yvette Cedex, France 7 Institut de Recherches Subatomiques (IN2P3/CNRS), BP 28, 67037 Strasbourg, France
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Motivations: K ∞ Skyrme & Gogny K = 235 12 MeV Relativistic MF K = 250 – 270 MeV E ISGMR (self-consistent CHF) Energy Functional E[ρ] K ∞ in nuclear matter (analytic) (N=Z and no Coulomb interaction) E( , ) = E( ,0) + a sym ( ) 2 +... 208 Pb neutron excess nucleus G. Colò et al. (Phys. Rev. C70 (2004) 024307) measure E ISGMR along an isotopic chain (unstable nuclei) probe the effect of the symmetry term N.B. : macroscopic method needs data on the nuclear chart Microscopic method
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56 Ni(d,d’) with the active target MAYA 56 Ni unstable (10 6 pps @ GANIL) A NEW EXPERIMENTAL METHOD 25cm 20cm 28cm 2 H gas He gas
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