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Shell evolution in exotic Ni isotopes

Shell evolution in exotic Ni isotopes. T. Marchi. 11 th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS SHELL MODEL AND NUCLEAR STRUCTURE: achievements of the past two decades Ischia, May 12 – 16 2014. Conclusion and Outlook. Introduction. Focus on 74 Ni.

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Shell evolution in exotic Ni isotopes

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  1. Shell evolution in exotic Ni isotopes T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS SHELL MODEL AND NUCLEAR STRUCTURE: achievements of the past two decades Ischia, May 12 – 16 2014

  2. Conclusion and Outlook Introduction Focus on 74Ni • Shell evolution along Ni isotopic chain, towards 78Ni. Shell evolution in exotic Ni isotopes • Existing data. • Intermediate energy Coulomb excitation (NSCL 09031): • Exotic Beam production; • Experimental setup; • Data analysis and B(E2)↑ extraction; • Comparison with SM calculations. T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS SHELL MODEL AND NUCLEAR STRUCTURE: achievements of the past two decades Ischia, May 12 – 16 2014

  3. Introduction [B. Pritychenko et al, At. Dat. AndNucl. Dat. Tab. 98, 4 (2012) 798] [N. Shimizu et al, Progr. Theo. Exp. Phys (2012) 01A205 ] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  4. Introduction [B. Pritychenko et al, At. Dat. AndNucl. Dat. Tab. 98, 4 (2012) 798] [N. Shimizu et al, Progr. Theo. Exp. Phys (2012) 01A205 ] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  5. Introduction [B. Pritychenko et al, At. Dat. AndNucl. Dat. Tab. 98, 4 (2012) 798] [N. Shimizu et al, Progr. Theo. Exp. Phys (2012) 01A205 ] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  6. Introduction Shell Evolution Proton ESPE for Ni isotopes See also: H. L. Crawford, PRL 110, 242701 (2013) on Fe/Cr isotopes. “twin experiment”. And S. M. Lenzi, PRC 82, 054301 (2010) [T. Otsuka, Phys Rev Lett 104.012501] Neutron ESPE for N=50 isotones and for Ni isotopes 0 Motivation: 1-Study the evolution of nuclear Shells far from stability, towards 78Ni. 2-Test model space and interactions far from stability. [B. Pritychenko et al, At. Dat. AndNucl. Dat. Tab. 98, 4 (2012) 798] [K. Sieja and F. Nowacki, Phys Rev C 85, 051301] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  7. Existing data – 74Co β-decay 74Ni T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  8. Existing data - proton scattering 74Ni (p,p’) extracted from proton inelastic scattering cross section using distorted wave theory. (ECIS97 code) Assuming comparable deformation lengths also for the neutron rich part of the chain: (p,p’)  C B(E2) = 1270(380) e2fm4 N=46 [N. Aoi et al, Phys. Lett. B 602, 302 (2010)] [B. Pritychenko et al, At. Dat. And Nucl. Dat. Tab. 98, 4 (2012) 798] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  9. 74Ni Radioactive ion beam production 74Ni ≈ 0.7 pps dp/p = 3% 86Kr34+ @ 140 AMeV 9Be399 mg/cm2 T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  10. 74Ni Experimental setup Focal Plane detectors Object scintillator S800 Analysis line S800 Spectrometer Secondary target position 197Au 640 mg/cm2 CAESAR array T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  11. 74Ni The S800 spectrometer and the CAESAR array CAESAR array CAESAR array + S800 spectrometer T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  12. 74Ni Beam Tagging and Particle Identification Focal plane PID Beam Tagging Runs without target T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  13. 74Ni Data analysis: particle and gamma ray time gates Energy-time gamma-rays gate: Impact parameter selection: T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  14. 74Ni Two main issues Background modeling Beam contamination Ungated PID Gated PID E (keV) EPAX: 76Cu 1p-1n K.O. : σ = 29 mb  NK.O. =18±9 Ng = 9 ±5 E (keV) T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  15. 74Ni Event by event analysis and gamma-ray spectra Fit: GEANT4 +exponential bkg [A. Winther and K. Alder, Nucl. Phys. A319, 518 (1979)]  Ng = 99 ± 28 = 148+50-52mb B(E2; 0+ -> 2+) = 642+216-226 e2 fm4 T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  16. Results [1] K. Sieja, F. Nowacki, Phys Rev C 85, 051301(R) (2012) K. Sieja, F. Nowacki, arXiv:1201.0373v1 (2012) S. M. Lenzi et al, Phys Rev C 82, 054301 (2010) [2] L. Coraggio, PRC 89, 024319 (2014) L. Coraggio et al., Prog. Part. Nucl. Phys 62, 135 (2009) [3] N. Shimizu et al., ProgrTheor Exp. Phys, 01A205 (2012) Y. Tsunoda et al., PRC 89, 031301(R) (2014) The B(E2; 0+→2+) value obtained in the intermediate energy Coulomb excitation provides new important information for the understanding of the Ni isotopic chain towards the 78Ni doubly magic nucleus. 1-The collectivity enhancement suggested by the (p,p’) experiment seems quenched when using purely electromagnetic probes; 2-The obtained values can be used to benchmark the Model Space and Interactions used for Shell Model Calculations far from stability. T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  17. Discussion and outlook Inelastic scattering data compared to Coulex results allow to disentangle the proton/neutron excitation matrix elements. For the 74Ni isotope, their difference could be an indication of the relative proton/neutron cores polarization leading to different deformation. A higher degree of accuracy is needed to constrain the B(E2) error bar and provide quantitative Mn/Mp ratio information. T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  18. Discussion and outlook Inelastic scattering data compared to Coulex results allow to disentangle the proton/neutron excitation matrix elements. For the 74Ni isotope, their difference could be an indication of the relative proton/neutron cores polarization leading to different deformation. A higher degree of accuracy is needed to constrain the B(E2) error bar and provide quantitative Mn/Mp ratio information. • Outlook: • 72Ni and 76Ni become key nuclei to understand the evolution of collectivity along the Ni chain. 76Ni still represents a challenge in terms of RIB production. • Two different experiments are under analysis: • 68 – 70 - 72Ni (p,p’) inelastic scattering at NSCL (GRETINA) – NSCL E12016 • 74Ni Coulex at RIKEN with higher beam intensity (~150 counts in the 2+ peak). T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  19. Collaboration T. Marchi,1, 2 G. De Angelis,1 J.J. Valiente-Dobón,1 V. Bader3, T. Baugher,3D. Bazin,3 J. Berryman,3A. Bonaccorso,4 R. Clark,5 L. Coraggio,6 E. L. Crawford,5 M. Doncel,7 E. Farnea,8 A. Gade,3 A. Gadea,9 A. Gargano,6 T. Glasmacher,3 A. Gottardo,1, 2 F. Gramegna,1N. Itaco,10,6 P.R. John,8,2 R. Kumar,11 S. M. Lenzi,8,2 S. Lunardi,8,2 S. McDaniel,3C. Michelagnoli,8,2D. Mengoni,8,2 V. Modamio,1 D.R. Napoli,1B. Quintana,12A. Ratkiewicz,3 F. Recchia,8,2 E. Sahin,1R. Stroberg,3D. Weisshaar,3 K. Wimmer,3 and R. Winkler3 1INFN Legnaro National Laboratories, Legnaro (Pd), Italy 2Department of Physics, Padua University, Padua, Italy 3National Superconducting Cyclotron Laboratory , Michigan State University, East Lansing, Michigan, USA 4INFN Sezione di Pisa, Pisa, Italy 5Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 6INFN Sezione di Napoli, Napoli, Italy 7Ionizing Radiations Laboratory, University of Salamanca, Spain 8INFN Sezione di Padova, Padova, Italy 9CSIC-IFIC, Valencia, Spain 10Dipartimento di Fisica, Università “Federico II”, Napoli, Italy 11Deenbandhu Chhoturam University of Science and Technology, Haryana, 131039 India 12Grupo de Fisica Nuclear, Universidade de Salamanca, Spain Thankyou!

  20. 74Ni CAESAR scintillator array [D. Weisshaar et al., NIM A 624, 615 (2010)] Experimental gamma-rays multiplicity CAESAR Resolution CAESAR Efficiency T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  21. 74Ni S800 Focal Plane Detectors P10 500 Torr 80% CF4 20% C4H10 [D. Bazin et al., NIM B 204, 629 (2003)] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

  22. Introduction [A. Gade, NuclPhys News23-4 (2013) 10] [T. Otsuka, A. Schwenk, NuclPhys News 22-4 (2012) 12] T. Marchi 11th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS Ischia, May 12 – 16 2014

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