Coulomb excitation of the neutron-rich Cu Coulomb excitation of the neutron-rich Cu isotopes and isomers using RILISisotopes 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 Leuven2CSNSM Orsay, France
3TU München, Germany4IKP Köln, Germany
5IPN Orsay, France6Heavy Ion Laboratory, Warsaw University, Poland
7University of Sofia, Bulgaria8Universita di Camerino, Italy
9National Research Center Demokritos, Greece10Lund University, Sweden
Funded by IAP Belgium, BMBF, EURONS
Beyond 68Ni by Coulomb excitation with RIBs
68Ni
+2p
+2n
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, 232502 (2005)).
N=4
0 N=5
0
B(E2;2+0+) by Coulex
g9/2
f7/2
40
p3/2
f5/2
p1/2
2828
protons neutronsprotons
Beyond 68Ni by Coulomb excitation with RIBs
n-rich Cu isotopes provide an excellent means for testing the proton-neutron residual interaction in this mass -region;
n-rich Cu beams @ ISOLDE: p (1.4 GeV) +UCx + resonant laser ionization (RILIS).
N=4
0 N=5
0
B(E2;2+0+) by Coulex
2005: Coulomb excitation of odd-odd 68,70Cu;
2006: Coulomb excitation of odd-mass 67,69,71,73Cu.
g9/2
f7/2
40
p3/2
f5/2
p1/2
2828
protons neutronsprotons
The odd-odd The odd-odd 68,70 68,70CuCu
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.
p3/2 g9/2 = 3-, 4- , 5- , 6-
g9/2
f7/2
40
p3/2
f5/2
p1/2
2828
68Cu39
g9/2
f7/2
40
p3/2
f5/2
p1/2
2828
70Cu41
084
T1/2=31.1 sT1/2=7.84 ns
722778
956
1350
T1/2=3.75 min
0.7 ns <T1/2 <4 ns
-
1+
2+
6-
(3-)
(4-)
(5-)
p3/
2g
9/2
p3/
2p
1/2
68Cu39
0
228242
T1/2= 33 s
506
T1/2= 6.6 s
6-
3-
(4-)
1+
(5-)
70Cu41
-
-
T1/2= 45.5 s
101
68Cu: J.D. Sherman et al. PLB67 (77) 257; T. Ishii, JAERI-Review, 2002-029, 25.70Cu: J. Van Roosbroeck et al., PRL92(2004)112501, J. Van Roosbroeck et al., PRC69(2004)034313.
68,7068,70CuCu
Coulex with post-accelerated 6- isomeric beams !E
2
E2
Isomeric Isomeric 68,7068,70Cu beams @ IsoldeCu beams @ Isolde
6-
1+ (g.s.)
68Cu
6- (g.s.)
1+
70Cu 3-
technique based on in-source laser spectroscopy (Ü. Köster et al., NIM B, 160, 528(2000); L. Weissman et al., PRC65, 024315(2000)).
set the laser frequency to select and maximize the production of the isomer of interest.
+ postacceleration by REX-ISOLDE
1+
6-
0
722
6-
1+
0
242
3-
101
Experimental set-up for Coulex @REX-ISOLDEExperimental set-up for Coulex @REX-ISOLDE
Miniball:
8 clusters, 3 X 6 fold segmented
120Sn
REX-ISOLDE
68m,70gCu (6-)E~2.83 MeV/u
PPACBeam
monitor
DSSD detector
~2 mg/cm2
Beam dump detector
(16o-53o)
• 4 quadrants
• 16 annular strips ()
• 24 sector strips ()
68,mCu (2.83 MeV/u) @ 120Sn (2.3 mg/cm2)
70Cu (2.83 MeV/u) @ 120Sn (2.3 mg/cm2)
851+
(2+)
6-
4-
(3-)722
(5-)
0
956178 (M1)
693
84
778E2
6-
(3-)
4-
(5-)
0
101
228
506
127 (M1) E2
Coulomb excitation of odd-odd 68,70Cu- first use of postaccelerated isomeric beams -
68Cu
70Cu
I. Stefanescu et al., PRL 98, 122701(2007).
coulex
coulex
*B(E2;6-4-) in 72Cu from R. Grzywacz et al., PRL 81, 766 (1998).
68,70Cu: I. Stefanescu et al., PRL 98, 122701(2007).
Comparison with shell-model calculationsComparison with shell-model calculations
protons
28p3/2
f5/2
p1/2
g9/2
f7/2
neutrons
28p3/2
f5/2
p1/2
g9/2
f7/2
40
Shell-model calculations for the valence space outside the 56Ni core (e=1.5e, e=0.5e) .
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.
1+
2+
6-
4-
(3-)722
0
3.75 min
31.1 s
5-
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, 035801(2002).
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
instantaneous depopulation of isomers in odd-odd nuclei based on their multiplet structure
possible scheme for triggered energy release in odd-odd nuclei
6868Cu: releasing the energy of the 6Cu: releasing the energy of the 6-- isomer isomer
I(I+1)
En
ergy
6-
E23-
4-
5-
1+
2+
M1
2006: Coulomb excitation of 2006: Coulomb excitation of 67,69,71,73 67,69,71,73CuCu
B. Zeidman et al., PRC 18, 2122(1978)/R. Grzywacz et al., PRL 81, 766 (1998) /S. Franchoo et al., PRL 81, 3100(1998).
Eex
(M
eV)
0
1
2
p3/2
f5/2
p1/2
p3/22+ (A-1Ni)
3/2-
5/2-
1/2-
7/2-
67Cu38
7/2-(f7/2)-1
69Cu4073Cu44
71Cu42
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
28
g9/2
f5/2
40
p3/2
p1/2
75Cu46
shell-model
g9/2
104Pd
7/2-
104Pd
104Pd
1/2-
5/2-
7/2-
5/2-
1/2-
7/2-
Coulomb excitation spectraCoulomb excitation spectra
120Sn
7/2-
(1/2-)
5/2- (1/2-)(5/2-)
(7/2-)
(3/2-)
p3/22+(72Ni)
1/2-
5/2-
7/2-
3/2-
p3/22+(68Ni)
(1/2-)(5/2-)
(7/2-)
(3/2-)
p3/22+(70Ni)
5/2-
1/2-
7/2-
3/2-
p3/22+(66Ni)
p3/2
f5/2
p1/2454
135
(1/2-)
67Cu (2.99 MeV/u) @ 104Pd (2 mg/cm2)
69Cu (2.97 MeV/u) @ 104Pd (2 mg/cm2)
71Cu (2.95 MeV/u) @ 104Pd (2 mg/cm2)
73Cu (2.88 MeV/u) @ 120Sn (1.7 mg/cm2)
73Ga
Experimental results (preliminary)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.
Experimental results (preliminary)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.
Experimental results (preliminary)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.
Summary and outlookSummary 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 72,75Cu @ REX-ISOLDE
new experimental set-up for transfer reactions, HIE-ISOLDE (5-10 MeV/u)
104Pd
104Pd
69Cu
1/2-
5/2-
7/2-
67Cu
5/2-
1/2-
7/2-
Experimental results (1)Experimental results (1)
3/2-
5/2-
1/2-
7/2-
7/2-
67Cu38
69Cu403/2-
5/2-
1/2-
7/2-
7/2-
DC for A=67
DC for A=69
2340
1670
1170
1115
1096
1213
1711
1871
(f7/2)-1
(f7/2)-1
p3/22+ (66Ni)
p3/22+ (68Ni)
71Cu(1/2-)5/2-
120Sn
Experimental results (2)Experimental results (2)
104Pd
7/2-
71Cu
71Ga
(1/2-)454 keV
(3/2-)
(5/2-)
(1/2-)
(7/2-)
(7/2-)
71Cu42
DC for A=71
DC for A=71
454
534
981
1190
(f7/2)-1
p3/22+ (70Ni)
Experimental results (3)Experimental results (3)
73Cu
73Ga
Laser ON
Laser OFF(3/2-)
(5/2-)
(1/2-)
(7/2-)
(7/2-)
73Cu44
DC for A=73
120Sn
7/2-
135
166
961
1010
(1/2-)
5/2-
(f7/2)-1
p3/22+ (72Ni)
1.4 GeV proton beam
Miniball
REX-ISOLDEXCu+XGa ~2.95 MeV/u
Resonant laser ionization (RILIS)
Radioactive beams of Radioactive beams of 67,69,71,7367,69,71,73Cu @ISOLDECu @ISOLDE
UCx target