Coulomb excitation and b-decay studies at (REX-)ISOLDE around Z = 28
J. Van de Walle – KVI - Groningen
1. ISOLDE and REX-ISOLDE ;2. Results around Z=28 :
Odd-A cupper isotopes (Z=29) ; Even-A zinc isotopes (Z=30) ; Even-A iron isotopes (Z=26) ;
REX-ISOLDE (high energy) :low energy Coulomb excitation < 3 MeV/u using the MINIBALL germanium array.
- Resonance Ionization Laser Ion Source brings in unique beams !- 30 - 60 keV beams (low energy)- Around 600 isotopes of 60 elements available- b-decay studies
ISOLDE and REX-ISOLDE
Mn (Z=25)
Ni (Z=28)
Cu (Z=29)
Zn (Z=30)
ISOTOPE Yields around Z = 28 : Zn, Cu, Ni, Mn RILIS ; UCx target – fission by 1.4 GeV protons – 2 mA ; 30 keV beams ; b-decay of 61-68Mn
Mass
Yiel
d /
mC
b-decay studies
ISOLDE and REX-ISOLDE
Mn (Z=25)
Ni (Z=28)
Cu (Z=29)
Zn (Z=30)
Mass
Yiel
d /
mC
ISOTOPE Yields including REX efficiency : Zn, Cu, Ni, Mn post-acceleration possible ; 61,62,63Mn/Fe, 68Ni, 67,69,71,73Cu and 74,76,78,80Zn.
ISOLDE and REX-ISOLDE
Specific nuclear structure questions :
Evolution of Z=28, N=40 and N=50 shell gaps at extreme isospin motivated by the "tensor part" of the strong interaction
Collectivity sets in around major shell gaps ;
Evolution of single particle energies ;
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
Tensor part pj>/< - nj’</> = attractive (pf5/2-ng9/2 , pp1/2-ng9/2 )pj>/< - nj’>/< = repulsive (pf7/2-ng9/2 , pp3/2-ng9/2 )
Results around Z=28 : introduction
Specific nuclear structure questions :
Evolution of Z=28, N=40 and N=50 shell gaps at extreme isospin motivated by the "tensor part" of the strong interaction
Collectivity sets in around major shell gaps ;
Evolution of single particle energies ;
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
Results around Z=28 : introduction
En
erg
y [M
eV]
Neutron Number
Ni
Zn
Fe
2+
4+
0+
En
erg
y [M
eV]
Neutron Number
Specific nuclear structure questions :
Evolution of Z=28, N=40 and N=50 shell gaps at extreme isospin motivated by the "tensor part" of the strong interaction
Collectivity sets in around major shell gaps ;
Evolution of single particle energies ;
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
Results around Z=28 : introduction
Ni
Zn
Fe
2+
4+
0+
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
l
Odd-A cupper isotopes (Z=29)
Results around Z=28 : Odd-A cupper isotopes
b-decay of neutron-rich Ni isotopes at LISOL facility (gas-cel)
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
l
Spectroscopic factors needed ! Shell model starts to reproduces this result 56Ni not a closed core (65% [1], 50% [2] closed core)[1] Honma PRC69 034335 (2004), [2] Otsuka PRL 81 1588 (1998)
Odd-A cupper isotopes (Z=29)
Results around Z=28 : Odd-A cupper isotopes
Coulomb excitation of neutron-rich Cu isotopes at REX-ISOLDE facility ("RILIS")
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
ll
llllllllll
Neutron number
onset of collectivity around N=40 ? E(2+1) !!!
neutron pair scattering at N=40 ? E(0+2) !!!
Influence of proton excitations across Z=28 ? Influence of neutron excitations across N=50 ?
Even-A zinc isotopes (Z=30)
Results around Z=28 : Even-A zinc isotopes
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
ll
llllllllll
Neutron number
onset of collectivity around N=40 ? E(2+1) !!!
neutron pair scattering at N=40 ? E(0+2) !!!
Influence of proton excitations across Z=28 ? Influence of neutron excitations across N=50 ?
Even-A zinc isotopes (Z=30)
Results around Z=28 : Even-A zinc isotopes
Z
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
llll llll
llllllllll
Results around Z=28 : Even-A zinc isotopes
N = 50 isotones
Early Ji-Wildenthal empirical effective interaction PRC 37, p. 1256 (1988)
Z
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
llll llll
llllllllll
Results around Z=28 : Even-A zinc isotopes
N = 50 isotones
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
llllllllll
llll
ORNL - Padilla-Rodal et al., PRL 94, 122501 (2005)
The benefit of post-accelerated RIBs !
Results around Z=28 : Even-A zinc isotopes
Z
N = 50 isotones
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
llllllllll
ll
REX-ISOLDE - Van de Walle et al., PRL 99, 142501 (2007)
The benefit of post-accelerated RIBs !
Z
Results around Z=28 : Even-A zinc isotopes
N = 50 isotones
JJ4B ep,en = 1.76,0.97[A. Lisetskiy, A. Brown, et al]
Z
f7/2llllllll
p1/2
f5/2p3/2
sd-shell
28
50
g9/240
p
llllllll
p1/2
f5/2p3/2
28
50
g9/240
f7/2
nsd-shell
llllllllllll
llllllllll
ll
G-matrix [M. Hjorth-Jensen] + monopole adjustments ep,en = 1.9,0.9[N. Smirnova et al]
Early Ji-Wildenthal empirical effective interaction PRC 37, p. 1256 (1988)
Results around Z=28 : Even-A zinc isotopes
N = 50 isotones
Neutron Number
.
Even–A iron isotopes (Z=26)
t2+Ljungval et al., PRC 81, 061301(R) (2010) +Rother et al., arXiv:1006.5297 v1 [nucl-ex]
Results around Z=28 : Even-A iron isotopes
Neutron Number
.
Even–A iron isotopes (Z=26)
Lenzi et al., "The land of deformation south of 68Ni"arXiv:1009.1846v1 [nucl-th]
Include pf7/2, nd5/2 orbitals in the valence space Z=28 shell gap determined from 80Zn B(E2), ep=0.5e
Results around Z=28 : Even-A iron isotopes
t2+Ljungval et al., PRC 81, 061301(R) (2010) +Rother et al., arXiv:1006.5297 v1 [nucl-ex]
Neutron Number
Even–A iron isotopes (Z=26)
Results around Z=28 : Even-A iron isotopes
Low energy Coulex : s(B(E2),Q(2+ ))
Lenzi et al., "The land of deformation south of 68Ni"arXiv:1009.1846v1 [nucl-th]
Include pf7/2, nd5/2 orbitals in the valence space Z=28 shell gap determined from 80Zn B(E2), ep=0.5e
t2+Ljungval et al., PRC 81, 061301(R) (2010) +Rother et al., arXiv:1006.5297 v1 [nucl-ex]
62Mn
Results around Z=28 : Even-A iron isotopes
62Mn
62Fe
2+
0+
4+
COULEX
b-decay
62Mn + 62Fe
Results around Z=28 : Even-A iron isotopes
Energy [keV]
Co
un
ts /
4 ke
V
419 keV
62Mn
62Fe
877 keV 2+
0+
4+
Gaudefroy et al., EPJA 23, 41-48 (2005)
(3,4)+
COULEX
Results around Z=28 : Even-A iron isotopes
419 keV
62Mn
62Fe
877 keV 2+
0+
4+(3,4)+
COULEX
preliminary
Results around Z=28 : Even-A iron isotopes
62Mn0.77(5) ms (*)
x (1+)
(3+,4+)
(*) Preliminary half lives 0+
62Cr
62Fe
2+
4+
Neutron Number
En
erg
y [M
eV]
b-decay
2+
4+
0+
2+
4+
0+
Ni
Fe
Results around Z=28 : Even-A iron isotopes
62Mn
0.15(1) ms (*)
0.77(5) ms (*)
x (1+)
(3+,4+)
(*) Preliminary half lives 0+
62Cr
814 keV : 152(13) ms
62Fe
2+
4+
0+
Neutron Number
En
erg
y [M
eV]
b-decay
2+
4+
0+
2+
4+
0+
Ni
Fe
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