Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Captures and Molecules …
Sandrine Courtin
Institut Pluridisciplinaire Hubert Curien, Département des Recherches Subatomiquesand Université Strasbourg I
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
88 20
20
28
28
50
50
82
82
126
-9.32
11.8 Now
N-rich around N = 20 – 28
How ? Transfer reactions transfer process / nucleon-nucleon spectroscopy
Ex : 40Ar (ELab = 255 MeV) + 208Pb (11/2007) n-rich ArWhere ? Legnaro (Prisma-Clara), GANILCollaboration : IPHC, Univ. Zagreb (S. Szilner et al.), Univ. Torino, LNL Legnaro (L. Corradi et al.), Univ. of West Scotland (R. Chapman et al.)
Theory : G. Pollarolo (Univ. Torino), E. Caurier, F. Nowacki (IPHC)
AM
E03-
LMD
, P
. Van
Isac
ker e
t A.E
.L. D
iepe
rink,
In
t. J
Mod
. Phy
s. E
15,1
371(
2006
)
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Clustering in light heavy-ions
How ? Narrow ‘molecular’ resonances, fragment, particle, decay Ex : (24Mg-24Mg) resonances in 48Cr
(12C - 12C) resonances in 24Mg (12C - 16O) resonances in 28Si
Where ? Legnaro (Prisma-Clara), Berkeley (Gammasphere), Triumf (Dragon + BGO), Argonne (Gammasphere+FMA)
Collaboration : IPHC, Univ. York (D. Jenkins et al.), Triumf (D. Hutcheon et al.) ANL (C. Lister et al.), Univ. of West Scotland (R. Chapman et al.)
Theory : J. Dudek (IPHC), K. Pomorski (Lublin) LSD Model S. Ohkubo. K. Yamashita (Univ. Kochi) CM D. Baye and P. Descouvemont (ULB) GCM J. Cseh and G. Lévaì (Atomki, Debrecen) ACM
(12C - 12C) resonances in 24Mg (12C - 16O) resonances in 28Si
Molecules Deformation -decay Radiative Capture Reactions : recent results
Now
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
12C(12C,)24Mg and 12C(16O,)28SiSetting the stage
Resonances ? NOC (F. Haas and Y. Abe, Phys. Rev. Lett. 46 (1981) 1667)
Radiative Capture : Light Particles vs Heavy-Ions
Light heavy-ions : 12C+12C 24Mg, 12C+16O 28Si Sandorfi et al. (BNL, ~ 1980) Narrow resonances @ Bc
No recoil, decay to g.s.
Narrow Resonances (150 keV), Et ~ h molecules
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Results on 12C(12C,)24Mg and 12C(16O,)28Si
First StageFirst Stage
Second StageSecond Stage
D.A
. Hut
cheo
n et
al.,
NIM
A 4
98, 1
90 (2
003)
.
ISAC I : RNBs / Stable (OLIS) 00°° spectrometer spectrometer Tof on 17 m Beam rejection 10Beam rejection 101313
Acceptance : cone half angle 20 mrad
gas/solid target system recoil detectors (DSSSD, …) BGO array ( = 50 % @ 5 MeV)
Measurements ON- and OFF resonance @ BC
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Results on 12C(12C,)24Mg and 12C(16O,)28Si12C+16O
Gamma spectrum (28Si)2+ → 0+
4+ → 2+
3+,0+, 3-
~14 MeV
12C+16OHighest energy -ray
25 MeV
~ 11 MeV
0 MeV28Si
20 MeV
~ 10 MeV
0 MeV24Mg
12C+12CHighest energy -ray
~ 10 MeV
S. C. et al., Fusion 06, San Servolo, AIP Conf. Proc. 853 (2006), S. C. et al., Journal of Physics G, London (2008).
~ 14 MeV
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Clusters ?
Shell Model ?16O, doubly magic …, 0+
2, 2+, 4+ …B(E2) (2+0+) = 27 W.u., B(E2) (4+ 2+) = 65 W.u.8Be, 9Be, 10Be12C (0+, Hoyle) …Model Space …
Cluster Models ?CM (Abe & Uegaki), ex : 24Mg-24Mg resonances in 48Cr.GCM, (Baye & Descouvemont), deformed structures, rotational bands.
AMD ?Ab initio (Horiuchi, Kanada En’yo)24Mg, 28Si, 32S, 36Ar, 40Ca, 28Mg Deformed structures, SD, clusters …Clusters in n-rich nuclei
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Results on 12C(12C,)24Mg and 12C(16O,)28SiTheory
What is the structure of those states ?What is the structure of those states ?
28Si(12C-160) Ohkubo and Yamashita, Phys.Lett. B 578 (2004) 304. 24Mg(12C-12C) P. Descouvemont and D. Baye, Phys.Lett. 169 B (1986) 143.
Links between low-lying members of these cluster bands ?Links between low-lying members of these cluster bands ?
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
2+ resonance ? (Ecm = 6 MeV)
simulationexperiment
Resonances strongly correlated to 24Mg and 28Si states Large part of the flux via doorway states around 10-11 MeV. ( threshold = 9.3 MeV and 10.0 MeV)
D.G. Jenkins, S. Courtin et al., Phys. Rev. C (in press)
Results on 12C(12C,)24Mg and 12C(16O,)28Si
12C+12C12C+16O
2 scenarii 1- States with a specific structure ? 2- Decay via T = 1 states through T = 1 M1 allowed transitions may be favoured in this N = Z nucleus …
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
© H
. Esb
ense
n, S
. Mis
icuR → 6.05
R → 6.9
6.09 → g.s.
R → g.s.
Lower energies ?What happens below BC and down to Eastro … ?
12C() 16O, Dragon data
E
Medium mass systems fusion X-sections, hindrance … Ex : 64Ni +64Ni, incompressibility, CC calc.
36S+48Ca, LNL, Legnaro, 10/2007 (20% below BC)
12C + 12C, 12C + 16O C.L. Liang, K.E. Rehm, B.B. Back and R.V.F. Janssens, PRC 75, 015803 (2007), 16O and 12C induced fusion. S extrapolated to low energies …
12C() 16O Reaction rate, = 0.01 fb @ EGamow Direct kin. (Stuttgart, M. Assuncao et al., PRC 73 (2006) 055801), no recoil Inverse kin. (Triumf, C. Matei et al. PRL 97 (2006) 242503) recoil with Dragon, new path …
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Next move
Shell model and mean field, a kind of unified view
TDHF, reaction mechanism at Bc and below as a function of the reacting time …
Identify the doorway states Giant resonances & molecular resonances … ?N-rich clusters ? new generation of scintillators (LaBr3(Ce)) + state-of-the-art spectro …
12C + 12C, why ?E
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
Breakup reactions 28Si 12C+16O, 24Mg 12C+12C
• 12C+16O breakup states to 45 MeV. C.J. Metelko et al., J. Phys. G29 (2003), 697 • Reaction 12C(20Ne,12C16O)@ ANL
• 12C+12C breakup states to 50 MeV C.J. Metelko et al., Phys.Rev. C68 (2003) 0544321• Reaction 12C(16O,12C12C)
RCRC
12C+16O et 12C+12C
Sandrine Courtin Atelier de l’ESNT Saclay, Feb. 4-6 / 2008
EM transitions between resonant states
Multinucleon transfer, far from stability (collab. L. Corradi, LNL) n-pairs transfers in n-rich nuclei fus very @ low E.
SPIRAL2
PARIS
Nuclear Molecules resonances and doorway states Gammasphere+FMA, AGATA, PARIS SPIRAL 2
24 Si detectors @ 45°+ highly efficient -array
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