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Halo effects
Study of halo effects in the Scattering of 11Li with heavy targets at energies around the
Coulomb barrier
On behalf of the E1104 Collaboration: IEMCSIC (Madrid)U.Sevilla – U.Huelva – U.York – U.Aarhus – U. Edingburg – U. St Mary – TRIUMF
MINISTERIO DE CIENCIAE INNOVACION
CONSEJO SUPERIORDE INVESTIGACIONESCIENTÍFICAS
E1104
Miguel Madurga
Halo Nuclei
Common “Structural” properties Rather inert core plus one or two barely unbound extra neutrons
Extended neutron distribution, large “radius”. “halo” Low binding energy Very few excited states –if any.
11Li 11Li Borromean Borromean HaloHalo
Reaction properties at near-barrier energies: Strong absorption in elastic channel Large cross section for fragmentation They are easily polarizable: - In the scattering process the forces between target and core/ halo are different distortion effects e.g. Coulomb dipole polarizability
100º
Vertical SS
SD
1 ... strips ... 16
Horizontal position
1 ... strip n ...16ΔE3Id:0
E3(n/p)Id:4
Top: 16 p, Botton: 1 p
50º
TargetsStrips
Beam
1 left
.. Strip
p .. r
ight 1
6
Horizo
ntal p
ositio
nΔE2(n/p)
Id:1
E2 (Pad)Id:5,Ch:2
Vertic
al po
sition
Top:
1 n, B
otton
16 n
30º
60º
E4(n/p)Id=3
16 ... Strips ... 1
Vertical SSSD
1 ... Strips n ...16
Horizontal position
ΔE4Id:0
Ch:0-15
Top: 1 p, Botton: 16 p
90º
140º
40º
Horizontal positionΔE1(n/p)
Id:2
E1 (Pad)Id:5,Ch:1
Vertical position
Top: 1 n, Botton: 16 n
1...Vertical Strips p...16
10º
1.45 1.90 0.822.0 mm Collimator
GSImg/cm2
70º
dE1
alpha particles
elastic
breakup
E1
Noise on first strip nearly to beam
Integrals after 82h:
detector breakup elastic 1 4378 238333 2 1899 5628 3 729 4 118
Beam 11Li, 2.7 MeV/u
11Li yield at monitor:1.8x10^9 counts, 2.2 MeV/u, 82h1.3x10^9 counts, 2.7 MeV/u, 119h
4300 pps