1. Coulomb excitation of the neutron-rich Cu isotopes and isomers using RILIS
Irina Stefanescu1, O. Ivanov1, J. Van de Walle1, N. Patronis1, D. Pauwels1, T. E. Cocolios1, N. Bree1, M. Huyse1, P. Van Duppen1
G. Georgiev2, T. Kröll3, P. Maierbeck3, A. Blazhev4, N. Warr4, S. Franchoo5, J. Iwanicki6, P. Napiorkowski6, K. Wrzosek6, D. Balabanski7, K. Gladnishki7, G. Rainovski7, G. Lo Bianco8, N. Blasi8, A. Lagoyannis9, T. Konstantinopoulos9, A. Ekström10
1IKS, KU Leuven
2CSNSM Orsay, France
3TU München, Germany
4IKP Köln, Germany
5IPN Orsay, France
6Heavy Ion Laboratory, Warsaw University, Poland
7University of Sofia, Bulgaria
8Universita di Camerino, Italy
9National Research Center Demokritos, Greece
10Lund University, Sweden
Funded by IAP Belgium, BMBF, EURONS

2. Beyond 68Ni by Coulomb excitation with RIBs
g9/2
f7/2 40
llllllll
llll
llllll ll
p3/2
f5/2
p1/2 28
protons
neutrons
N=50
N=40
B(E2;2+0+) by Coulex
70Ni (68Ni+2n) and 70Zn (68Ni+2p) show large collectivity at low excitation energies;
tensor force: shifts and re-ordering of the single-particle orbits  erosion of the Z=28 and N=40 gaps (T. Otsuka, PRL 95, (2005)).
+2p
68Ni
+2n

3. Beyond 68Ni by Coulomb excitation with RIBs
g9/2
f7/2 40
llllllll
llll
llllll ll
p3/2
f5/2
p1/2 l 28
protons
neutrons
N=40
N=50
B(E2;2+0+) by Coulex
2005: Coulomb excitation of odd-odd 68,70Cu;
2006: Coulomb excitation of odd-mass 67,69,71,73Cu.
n-rich Cu isotopes provide an excellent means for testing the proton-neutron residual interaction in this mass -region;
n-rich Cu ISOLDE: p (1.4 GeV) +UCx + resonant laser ionization (RILIS).

4. The odd-odd 68,70Cu 70Cu41 68Cu39 p3/2  g9/2 = 3-, 4- , 5- , 6-
f7/2 40
llllllll
llll
llllll l
p3/2
f5/2
p1/2 28  
70Cu41 ll
g9/2
f7/2 40
llllllll
llll
llllll l
p3/2
f5/2
p1/2 28  
68Cu39
level schemes dominated by multiplets originating from the coupling of the odd proton with the odd neutron;
B(E2) values within the states of the p3/2  g9/2 multiplet offers important information about the p-n residual interaction across N=40.

5. 68,70Cu 1+ 2+ 6-
(3-)
(4-)
(5-)
p3/2g9/2
p3/2p1/2
Coulex with post-accelerated 6- isomeric beams ! E2
1350
956
(5-)
506
778
0.7 ns <T1/2 <4 ns
722
T1/2=3.75 min 1+
242
T1/2= 6.6 s -
(4-)
228 84
101
T1/2=7.84 ns 3-
T1/2= 33 s
T1/2=31.1 s 6-
T1/2= 45.5 s - -
68Cu39
70Cu41
68Cu: J.D. Sherman et al. PLB67 (77) 257; T. Ishii, JAERI-Review, , 25.
70Cu: J. Van Roosbroeck et al., PRL92(2004)112501, J. Van Roosbroeck et al., PRC69(2004)

6. Isomeric 68,70Cu beams @ Isolde
technique based on in-source laser spectroscopy (Ü. Köster et al., NIM B, 160, 528(2000); L. Weissman et al., PRC65, (2000)).
set the laser frequency to select and maximize the production of the isomer of interest. 6-
1+ (g.s.)
68Cu 1+ 6-
722 
6- (g.s.) 3-
70Cu 6- 1+
242  3-
101 1+
+ postacceleration by REX-ISOLDE

7. Experimental set-up for Coulex @REX-ISOLDE
Miniball:
8 clusters, 3 X 6 fold segmented
4 quadrants
16 annular strips ()
24 sector strips ()
DSSD detector
(16o-53o)
68m,70gCu (6-)
REX-
ISOLDE
E~2.83 MeV/u
Beam dump detector
PPAC
120Sn
Beam
~2 mg/cm2
monitor

8. 68Cu 70Cu Coulomb excitation of odd-odd 68,70Cu
- first use of postaccelerated isomeric beams -
68,mCu ( Sn (2.3 mg/cm2) 85 1+
(2+) 6- 4-
(3-)
722
(5-)
956
178 (M1)
693 84
778 E2
coulex
68Cu
70Cu ( Sn (2.3 mg/cm2) 6-
(3-) 4-
(5-)
101
228
506
127 (M1) E2
70Cu
coulex
I. Stefanescu et al., PRL 98, (2007).

9. Comparison with shell-model calculations
Shell-model calculations for the valence space outside the 56Ni core (e=1.5e, e=0.5e) .
protons 28
p3/2
f5/2
p1/2
g9/2
f7/2
llllllll l
neutrons
llll
llllll 40 ll
*B(E2;6-4-) in 72Cu from R. Grzywacz et al., PRL 81, 766 (1998).
68,70Cu: I. Stefanescu et al., PRL 98, (2007).
collectivity in 70Cu influenced by the stabilizing effect of 68Ni;
the poor agreement between the experiment and theory for 68,72Cu points to the importance of proton excitations across the Z=28 shell gap.

10. 68Cu: releasing the energy of the 6- isomer1+ 2+ 6- 4-
(3-)
722
3.75 min
31.1 s 5-
triggered -emission of high K-isomers extensively investigated by Coulomb depopulation, irradiation with bremsstrahlung, synchrotron radiation or X-rays
depopulation scheme based on K-mixing
178Hf: A.B. Hayes et al, PRL 89(2002)/PRL 96(2006);
180Ta: C. Schlegel et al., PRC 50, 2198(1994),
D. Belic et al., PRC 65, (2002).
instantaneous depopulation of isomers in odd-odd nuclei based on their multiplet structure
possible scheme for triggered energy release in odd-odd nuclei
I(I+1)
Energy 6- E2 3- 4- 5- 1+ 2+ M1

11. 2006: Coulomb excitation of 67,69,71,73Cu28
g9/2
f5/2 40
p3/2
p1/2 ll l
(f7/2)-1
3/2-
5/2-
1/2-
7/2-
67Cu38
Eex (MeV) 2
69Cu40
p3/22+ (A-1Ni)
p1/2
71Cu42 1
f5/2
shell-model
p3/2
73Cu44
75Cu46
g9/2
B. Zeidman et al., PRC 18, 2122(1978)/R. Grzywacz et al., PRL 81, 766 (1998) /S. Franchoo et al., PRL 81, 3100(1998).
rapid decrease of the energy of the f5/2 orbital beyond N=40 (monopole migration)
systematic study of the evolution of collectivity across N=40 by Coulomb excitation

12. Coulomb excitation spectra
67Cu ( Pd (2 mg/cm2)
71Cu ( Pd (2 mg/cm2)
5/2-
1/2-
7/2-
3/2-
p3/22+(66Ni)
p3/2
f5/2
p1/2
(1/2-)
(1/2-)
(5/2-)
(7/2-)
(3/2-)
p3/22+(70Ni)
454
5/2-
7/2-
1/2-
7/2-
104Pd
104Pd
69Cu ( Pd (2 mg/cm2)
73Cu ( Sn (1.7 mg/cm2)
1/2-
5/2-
7/2-
3/2-
p3/22+(68Ni)
(1/2-)
(1/2-)
(5/2-)
(7/2-)
(3/2-)
p3/22+(72Ni)
135
73Ga
1/2-
5/2-
5/2-
7/2-
120Sn
104Pd
7/2-

13. Experimental results (preliminary)
rapid decrease of the energy of the 5/2- state beyond N=40 followed by a decrease in collectivity;
rapid decrease of the energy of the ½- state beyond N=40 followed by an increase in collectivity.
low energy, high B(E2). Deformation?
R.L. Robinson et al., Phys. Rev. 134, B567, 1964.

14. Experimental results (preliminary)
B(E2; 7/2-  3/2-)  B(E2; 2+  0+) in agreement with the proposed p3/2 2+ nature for the 7/2- states;
B(E2; 7/2-  3/2-) : minimum collectivity at N=38;
trend in the odd-Cu isotopes similar to that shown by the even-even Zn isotopes.

15. Experimental results (preliminary)
B(E2; 7/2-  3/2-)  B(E2; 2+  0+) in agreement with the proposed p3/2 2+ nature for the 7/2- states;
B(E2; 7/2-  3/2-) : minimum collectivity at N=38;
trend in the odd-Cu isotopes similar to that shown by the even-even Zn isotopes.
strong polarization of the 66Ni core by the p3/2 proton.

16. Summary and outlook
2005: REX-ISOLDE postaccelerates first isomeric beams;
postaccelerated isomeric beams to be used for transfer reactions, magnetic moment measurements, etc;
68Cu: first clear evidence for instantaneous depopulation of a nuclear isomer;
measured B(E2; 6- 4-) indicate a fragile stabilizing effect of the Z=28 and N=40 gaps;
2006: systematic study of the evolution of collectivity across N=40 by Coulomb excitation with beams of 67,69,71,73Cu;
71,73Cu: coexistence of a deformed ½- state with a single-particle-like 5/2- level.
Summer 2007: beamtime accepted for Coulex of REX-ISOLDE
new experimental set-up for transfer reactions, HIE-ISOLDE (5-10 MeV/u)

17. Experimental results (1)
67Cu
7/2-
2340
(f7/2)-1
5/2-
7/2-
1670
p3/22+ (66Ni)
1/2-
7/2-
1/2-
1170
104Pd
5/2-
1115
67Cu38
DC for A=67
3/2-
1871
69Cu
7/2-
p3/22+ (68Ni)
(f7/2)-1
7/2-
1711
1/2-
5/2-
1213
5/2-
7/2-
104Pd
1/2-
1096
69Cu40
DC for A=69
3/2-

18. Experimental results (2)
(1/2-)
71Cu
454 keV
7/2-
(7/2-)
1190
p3/22+ (70Ni)
(f7/2)-1
(7/2-)
981
104Pd
71Ga
(5/2-)
534
DC for A=71
(1/2-)
454
71Cu42
71Cu
(1/2-)
(3/2-)
5/2-
120Sn
DC for A=71

19. Experimental results (3)
DC for A=73
(1/2-)
73Cu
5/2-
Laser ON
(7/2-)
1010
(f7/2)-1
73Ga
120Sn
p3/22+ (72Ni)
(7/2-)
961
7/2-
(5/2-)
166
(1/2-)
135
73Cu44
Laser OFF
(3/2-)

20. g9/2 f5/2 f7/2 protons neutrons j> = l+1/2 j< = l’-1/2

21. Radioactive beams of 67,69,71,73Cu @ISOLDE
1.4 GeV proton beam
UCx target
REX-ISOLDE
Resonant laser ionization (RILIS)
XCu+XGa ~2.95 MeV/u
Miniball

22. 68Cu
6- beam
68Cu
1+ beam