measurement of the gmr and the gqr in unstable nuclei using the maya active target
DESCRIPTION
Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target. C. Monrozeau (Ph. D), E. Khan, Y. Blumenfeld. Motivations: exotic modes ?. Few measurements on GR in unstable nuclei IVGDR. GQR and GMR soft modes are predicted !. - PowerPoint PPT PresentationTRANSCRIPT
Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target
C. Monrozeau (Ph. D), E. Khan, Y. Blumenfeld
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
Motivations: equation of state
• GMR breathing mode density variation around 0 (few %)
Nuclear equation of state
EISGMR along an isotopic chain (unstable nuclei)
D.T.Khoa et al. Nucl. Phys. A602 (1996) 98
evolution of incompressibility with asymmetry
N Z
A
Neutron stars
and neutron excess
determination of K
(symmetry energy term)
: density
D.H. Younblood et al, Phys. Rev. Lett 76, 1429 (1996)
58Ni ’=240 MeV
Inelastic scattering : (d,d’) ’@ E 25 A.MeV
GQR
GMR
GR in 58Ni : analysis
mixing 0+ and 2+
Experimental probes for isoscalar giant resonances
reverse kinematics
unstablenuclei
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/cm2
(6,3 mg/cm2 CD2 )
deuteron kinematics 56Ni(d,d’) @ 50 MeV/A
cathod
Frisch grid
beam
amplification wires
pads (cathod)
detection zone
active zone
MAYA
56Ni @ 50 MeV/A 5.104 pps
• July 2005, GANIL• SISSI beam
Experimental setup
Au foil
Drift
chamber
Ionisation
chamber
Moving flap
Si wall
CsI wall
Diamond
56Ni (5.104 pps)
50 A.MeV
+ contaminants
Results
d breakup
56Ni excitation energy spectrum
recoiling d kinematics
Analysis with gaussian fit
E* (MeV)
Cou
nts/
MeV
Reaction : DWBA with double folding using HF and RPA 56Ni gs and transition densities
Multipole Decomposition Analysis
• Isoscalar GMR and GQR measured in the 56Ni unstable nucleus• Use of MAYA active target with d gas• 16h of 104 pps beam• Results compatible with the 58Ni (stable) data• The method works !
•Improvements : identification & d breakup, reaction model
• Next : neutron rich Ni isotopes, 132Sn ACTAR active target
Summary & outlooks
first (p,p’) experiment
in inverse kinematics !
G. Kraus et al. Phys Rev. Lett. 73 (1994) 1773
Collaboration
C.Monrozeau1, E.Khan1, Y. Blumenfeld1, W. Mittig5, D.Beaumel1, M.Caamaño2,D.Cortina-Gil2, C-E.Demonchy3, N.Frascaria1, U.Garg4, M.Gelin5, A.Gillibert6, D.Gupta1, N.
Keeley6, F.Maréchal7, A.Obertelli6, P.Roussel-Chomaz5, J-A.Scarpaci1
1 Institut de Physique Nucléaire (IN2P3/CNRS), 91406 Orsay Cedex, France2 Univ. Santiago de Compostela, E-15706 Santiago de Compostela, Spain3 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 USA5 GANIL (DSM/CEA, IN2P3/CNRS), BP 5027, 14076 Caen Cedex 5, France6 CEA/DSM/DAPNIA/SPhN, Saclay, 91191 Gif-sur-Yvette Cedex, France7 Institut de Recherches Subatomiques (IN2P3/CNRS), BP 28, 67037 Strasbourg, France
Motivations: K∞
Skyrme & GognyK = 235 12 MeV
Relativistic MF K = 250 – 270 MeV
EISGMR (self-consistent CHF)
Energy Functional E[ρ]
K∞ in nuclear matter (analytic)(N=Z and no Coulomb interaction)
E(,) = E(,0) + asym() 2 +...
208Pb neutron excess nucleus G. Colò et al. (Phys. Rev. C70 (2004) 024307)
measure EISGMR 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
56Ni(d,d’) with the active target MAYA
56Ni unstable (106 pps @ GANIL)
A NEW EXPERIMENTAL METHOD
25cm
20cm
28cm
2H gas2H gasHe gas