1 / 22

Coulomb excitation of the neutron-rich Cu isotopes and isomers using RILIS

Coulomb excitation of the neutron-rich Cu isotopes and isomers using RILIS. Irina Stefanescu 1 , O. Ivanov 1 , J. Van de Walle 1 , N. Patronis 1 , D. Pauwels 1 , T. E. Cocolios 1 , N. Bree 1 , M. Huyse 1 , P. Van Duppen 1.

annabella-oral
Download Presentation

Coulomb excitation of the neutron-rich Cu isotopes and isomers using RILIS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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. g9/2 ll 40 p1/2 ll f5/2 llllll p3/2 ll llll 28 28 f7/2 llllllll llllllll protons protons neutrons B(E2;2+0+) by Coulex Beyond 68Ni by Coulomb excitation with RIBs N=50 N=40 • 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)). +2p 68Ni +2n

  3. g9/2 ll 40 p1/2 ll f5/2 llllll p3/2 l llll 28 28 f7/2 llllllll llllllll N=50 protons protons neutrons N=40 B(E2;2+0+) by Coulex • 2005: Coulomb excitation of odd-odd 68,70Cu; • 2006: Coulomb excitation of odd-mass 67,69,71,73Cu. 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).

  4. g9/2 g9/2 l l 40 40 p1/2 p1/2 ll f5/2 f5/2 llllll llllll p3/2 p3/2 l llll l llll     28 28 28 28 f7/2 f7/2 llllllll llllllll llllllll llllllll 70Cu41 68Cu39 The odd-odd 68,70Cu p3/2  g9/2 = 3-, 4- , 5- , 6- • 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. Coulex with post-accelerated 6- isomeric beams ! (5-) p3/2g9/2 (4-) E2 (3-) 6- E2 2+ p3/2p1/2 1+ 68,70Cu 1350 956 506 (5-) 778 0.7 ns <T1/2 <4 ns 722 T1/2=3.75 min 1+ 242 T1/2= 6.6 s - 228 (4-) 101 84 3- T1/2=7.84 ns T1/2= 33 s 0 0 6- T1/2=31.1 s T1/2= 45.5 s - - 68Cu39 70Cu41 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.

  6. 6- 6- 722  1+ 242 68Cu  1+ 0 101  3-  6- 0  1+ (g.s.) 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, 024315(2000)). • set the laser frequency to select and maximize the production of the isomer of interest. 6- (g.s.) 3- 70Cu 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. (5-) 4- 956 E2 178 (M1) 778 (3-) 6- 722 693 84 (2+) 85 1+ 0 (5-) 506 228 4- E2 127 (M1) (3-) 101 6- 0 Coulomb excitation of odd-odd 68,70Cu - first use of postaccelerated isomeric beams - • 68,mCu (2.83 MeV/u) @ 120Sn (2.3 mg/cm2) coulex 68Cu • 70Cu (2.83 MeV/u) @ 120Sn (2.3 mg/cm2) 70Cu coulex I. Stefanescu et al., PRL 98, 122701(2007).

  9. g9/2 g9/2 l p1/2 40 p1/2 ll f5/2 f5/2 llllll p3/2 p3/2 l llll 28 28 f7/2 f7/2 llllllll llllllll protons neutrons Comparison with shell-model calculations Shell-model calculations for the valence space outside the 56Ni core (e=1.5e, e=0.5e). *B(E2;6-4-) in 72Cu fromR. Grzywacz et al., PRL 81, 766 (1998). 68,70Cu: I. Stefanescu et al., PRL 98, 122701(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. 5- 4- (3-) 722 6- 3.75 min 2+ 1+ 0 31.1 s 5- 4- E2 3- M1 Energy 6- 2+ 1+ I(I+1) 68Cu: releasing the energy of the 6- isomer • 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, 035801(2002). • instantaneous depopulation of isomers in odd-odd nuclei based on their multiplet structure • possible scheme for triggered energy releasein odd-odd nuclei

  11. g9/2 ll p1/2 7/2- 40 f5/2 l p3/2 7/2- 28 1/2- 5/2- 3/2- 71Cu42 67Cu38 69Cu40 2006: Coulomb excitation of 67,69,71,73Cu (f7/2)-1 Eex (MeV) 2 p3/22+ (A-1Ni) p1/2 1 f5/2 shell-model p3/2 0 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. p3/22+(66Ni) 7/2- p3/22+(70Ni) (7/2-) p1/2 1/2- f5/2 (5/2-) 5/2- (1/2-) p3/2 3/2- (3/2-) p3/22+(68Ni) 7/2- p3/22+(72Ni) (7/2-) 5/2- 1/2- (5/2-) (1/2-) 3/2- (3/2-) Coulomb excitation spectra • 67Cu (2.99 MeV/u) @ 104Pd (2 mg/cm2) • 71Cu (2.95 MeV/u) @ 104Pd (2 mg/cm2) (1/2-) 454 5/2- 7/2- 1/2- 7/2- 104Pd 104Pd • 69Cu (2.97 MeV/u) @ 104Pd (2 mg/cm2) • 73Cu (2.88 MeV/u) @ 120Sn (1.7 mg/cm2) (1/2-) 135 73Ga 1/2- 5/2- 5/2- 7/2- 120Sn 104Pd 7/2-

  13. low energy, high B(E2). Deformation? 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. 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. strong polarization of the 66Ni core by the p3/2 proton. 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.

  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 72,75Cu @ 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. j> = l+1/2 g9/2 f5/2 j< = l’-1/2 f7/2 j> = l’+1/2 protons neutrons

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

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

More Related