Coulomb excitation and b -decay studies at (REX-)ISOLDE around Z = 28

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


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.


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





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


En

erg

y [M

eV]

Neutron Number

Ni

Zn

Fe

2+

4+

0+

En

erg

y [M

eV]

Neutron Number





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


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

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


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


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 !


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


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)


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

.


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



Neutron Number



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


62Mn


62Mn

62Fe

2+

0+

4+

COULEX

b-decay

62Mn + 62Fe


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


419 keV

62Mn

62Fe

877 keV 2+

0+

4+(3,4)+

COULEX

preliminary


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


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

... thanks !

Coulomb excitation and b -decay studies at (REX-)ISOLDE around Z = 28

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