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Shell and Shape effects investigated at (REX) ISOLDE

Shell and Shape effects investigated at (REX) ISOLDE. Elisa Rapisarda. The richness of Nuclear properties. 82. N=Z. 50. 126. 28. 82. 2 0. 50. 8. 28. CERN ISOLDE Isotope Separator On-Line DEvice. ISOLDE: • delivers high-quality beams of a wide range of radioactive isotopes

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Shell and Shape effects investigated at (REX) ISOLDE

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  1. Shell and Shape effects investigated at (REX) ISOLDE Elisa Rapisarda

  2. The richness of Nuclear properties 82 N=Z 50 126 28 82 20 50 8 28

  3. CERN ISOLDE Isotope Separator On-Line DEvice ISOLDE: • delivers high-quality beams of a wide range of radioactive isotopes • uniquepositionworld-wide • post-acceleration of the existing ISOLDE beams with REX-ISOLDE up to 3 MeV/u RILIS: ResonantIonization Laser Ion Source

  4. CERN ISOLDE Isotope Separator On-Line DEvice WITCH GHM GLM WINDMILL COLLAPSE CRIS MINIBALL ISOLTRAP

  5. Down & Up Along the Nuclear Chart • Shape-coexistence • Coulomb Excitation Hg, Po, Pb, Ra, Rn; • +/EC of Pb, Tl; • Laser spectroscopy Po, Pb, Tl; • -decay • Massmeasurements N=104 82 N=40 50 126 • Evolution of Shell structure • Coulomb Excitation Cu, Zn, … ; • Transfer reaction (d,p), (3He,p); • -decay of Mn, Fe, Co, Ni, …; • Laser spectroscopy Co, Ni, Cu, …; • Massmeasurements 28 82 50

  6. N=40 and Coulexof the Cu isotopes N=50 N=40 • n-rich Cu isotopes provide an excellent means for testing the proton-neutron residual interaction in this mass -region; • 2003 Mass measurement ISOLTRAP and β-decay; • 2005-2008: Coulomb excitation of odd-odd 68,70Cu; • 2006: Coulomb excitation of odd-mass 67,69,71,73Cu. • high E(2+) in 68Ni (R. Brodaet al., PRL 74 (95) 868) • low B(E2, 0+ 2+) (Sorlinet al., PRL 88 (2002)) • proposed new magic number N=40 Coulomb excitation of isomericstates of 70Cu

  7. g9/2 l 40 p1/2 ll f5/2 llllll p3/2 l llll 506 (10) (5-)   28 28 E2 f7/2 1+ 242 llllllll llllllll T1/2= 6.6 s 228 4- 70Cu41 101 3- T1/2= 33 s 0 6- T1/2= 45.5 s - 70Cu41 The odd – odd 70Cu • the low-energy level schemes dominated by multiplets originating from the coupling of the odd proton with the odd neutron p3/2  g9/2 = 3-, 4-, 5-, 6-or p3/2  p1/2 = 1+, 2+ • 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. V. Paar Nucl.Phys.A331(1979)16 70Cu: J. Van Roosbroeck et al., PRL92(2004)112501, J. Van Roosbroeck et al., PRC69(2004)034313 70Cu: J. D. Sherman et al., Phys.Lett. B67(1977)275 68,70Cu: I. Stefanescu et al., Phys.Rev. Lett 98(2007)122701 Mass Measurement, -decay  Transfer reaction 70Zn(t,3He)70Cu  Coulomb Excitation Coulomb excitation of isomericstates of 70Cu

  8. IsomericBeamsfrom REX-ISOLDE 6- (g.s.) 3- 1+ 70Cu 242  101 3-  6- 0 1+  • 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. J. Van Roosbroeck et al., PRL92(2004)112501 + postacceleration by REX-ISOLDE Coulomb excitation of isomericstates of 70Cu

  9. 6- (g.s.) 3- 70Cu 242 1+  101 3-  0 6- 1+  Experimentaldetails 70Cu on 120Sn Beam energy: 2,83 MeV/u Beam Intensity: 5 X 105pps 70Cu/70Ga = 50%/50% 70Cu/70Ga = 80%/20% 70Cu: 6- 72% 3- 25% 1+ less than 3% 70Cu: 6- 86% 3- 7% 1+ 7% Isomeric Composition determined from characteristic beta decay lines Inclusive excitation cross-section Inclusive excitation cross-section disentangle  (6-  XXX) and (3-  XXX) 68,70Cu: I. Stefanescu et al., Phys.Rev. Lett 98(2007)122701 Coulomb excitation of isomericstates of 70Cu

  10. 70Ga contamination 70Ga and70Cu impinges both on target The separator is not able to separate 70Cu from 70Ga Laser ON70Cu + 70Ga Laser ON – Laser OFF to disentangle Cu interaction from Ga interactions Laser OFF70Ga Laser ON-OFFmode Gacontribution can be precisely subtracted provided a precise normalization of Laser ON laser OFF run Coulomb excitation of isomericstates of 70Cu

  11. ExperimentalSetup REX- ISOLDE 70Cu 2,9 MeV/u on 120Sn 2,3 mg/cm2 Coulomb excitation of isomericstates of 70Cu Coulomb excitation of isomericstates of 70Cu

  12. Coulomb Excitationof70,gsCu and 70,m1Cu 127 keV A=70DC 511 keV 5- (506)  511 511 (M1) 228 4- 127 (M1) E2 A=120DC 3- 101 E2 6- 0 1171 keV Coulomb excitation of isomericstates of 70Cu

  13. 5- 511 4- 228 127 keV 3- 101 T1/2 = 33 s 0 T1/2= 44.5 s 6- 70Cu Cross Section: 127 KeV DC for A=70 70Cu (4-  3-) 127 keV Measurement of the (4-  3-) cross section in both experiments Isomeric Composition of the 70Cu beam is known Disentangle the  (6-  4-) and (3-  4-) • CLX code • Matrix element 0.30(4) eb • B(E2, 6- 4- ) = 69(9) e2 fm4 • CLX code • Matrix element = 0.23(3) eb • B(E2, 3- 4- ) = 73(10) e2 fm4 Coulomb excitation of isomericstates of 70Cu

  14. Cross-Section 511 KeV Challenge to measure 5- (506)  511 511 keV ??? 4- 228 70Cu (5-  6-) 511 keV DC for A=70 3- 101 T1/2 = 33 s 0 T1/2= 44.5 s 6- 70Cu Assuming only (3-  5-) excitations • CLX code • Matrix element 0.308(19) eb • B(E2, 3- 5- ) = 136(15) e2 fm4 Upper Limit Coulomb excitation of isomericstates of 70Cu

  15. Shell Models: comparison Large Shell-Model calculations with ANTOINE code Systematics of the 6- 4- transition SMII Calculationsby K. Sieja SMI Calculationsby N. Smirnova • hybrid interaction (S.Lenziet al., PRC82, 05430(2010))+ evolution of the proton gap from 68Ni to 78Ni; • model space is1f7/21f5/22p3/22p1/2for protons and 1f5/22p3/22p1/21g9/22d5/2for neutrons outside the 48Ca inert core; • realistic interaction (M. Hjorth-Jensen et al. , Phys.Rep.26(2004) • model space is1f5/22p3/22p1/21g9/2outside the 56Ni inert core; 2d5/2 1g9/2 2p1/2 2p3/2 1f5/2 Neutrons excitations across N=50 1g9/2 2p1/2 2p3/2 1f5/2 • NO proton-core excitations • NO neutron-core excitations Proton excitations across Z=28 1f7/2 N=28 Z=28 N=28 Z=20 Coulomb excitation of isomericstates of 70Cu

  16. Down & Up Along the Nuclear Chart Shape-coexistence 82 Shell structure N=40 50 126 28 82 50

  17. A classicalexample: 186Pb 0+ 0+ 0+ A.N. Andreyev et al., Nature 405(2000)430 • Shape coexistence = proximity of spherical and/or deformed shapes(s) at low energy (E < few MeV) • 186Pb: most dramatic examples where the three lowest lying states are 0+ states of three different shapes within less than 700 keV. Probe shape-coexistence in 182Hg via -decay of 182Tl

  18. Shapecoexistence in Hg isotopes excitedprolate band slightlyoblateground state band Mid-shell N = 126 Evidence for shape coexistence in systematic energy levels: flat behaviour of the spherical states against parabolic intrusion of the deformed states with a minimum at mid-shell N = 104. • 2008: Coulomb excitation of even-even182-184-186-188Hg; • 2010-2011: -decay and laser spectroscopy of odd-odd 178-180-182-184-186Tl; • 2010-2011: laser spectroscopy of odd-even 179-181-183-185-187Tl; Probe shape-coexistence in 182Hg via -decay of 182Tl

  19. Reorientation in Coulomb Excitation 2+ 0+ The cross section for exciting the 2+ state DOES NOT only depend on its reduced transition probability B(E2: 0+ -> 2+), but also on the diagonal matrix element <2+||M(E2)||2+>. Probe shape-coexistence in 182Hg via -decay of 182Tl

  20. 2+ 0+ Coulomb Excitation of 182,184, 186,188Hg Measurement of the nuclearshapes DIRECTLY Obtain sensitivity on the diagonal matrix element of the first excited state by scanning the center of mass angular range! • To help fit: • precise level scheme; • decayproperties (E0 component); • lifetimemeasurements • The detected γyields of the photo peaks can be used to extract: • transitional matrix elements (B(E2) values) • diagonal matrix elements (quadrupole moments) • Program GOSIA: by fitting the matrix elements to produce the obtained γyields by a χ2 minimization. (T. Czosnyka et al, GOSIA2) Probe shape-coexistence in 182Hg via -decay of 182Tl

  21. Spectroscopymethods What are the observables (“Shape coexistence in atomic nucleus”, K.Heyde and J.Wood, Rev.Mod.Phys., in press) 182Tl 182Hg 186Pb 190Po in beam 0+ J. Heese et al. PLB302(1993) 390  decay A. Andreyev et al. Nature 405 (2000) 430 6+ 4+ h.s. l.s. Ground State properties Massmeasurements (direct,  decay) Laser Spectroscopy 2+ 0+ T. Grahn et al. PRC80(2009) 014324 0+  decay 180Hg, J.Elsevier et al., PRC 84, (2011) 034307 0+ Transfer reactions 4+ 2+ 0+ 0+ E0 component Coulex T. Cocolios et al. PRL106(2011) 052503 H. De Witte et al. PRL98(2007) 112502 N. Bree & A. Petts Probe shape-coexistence in 182Hg via -decay of 182Tl

  22. -decay spectroscopy [1] K.S. Bindraet al., Phys. Rev. C, 51 (1995) 401 t1/2=3.1s 126 182Tl 82 b+/EC a 4% 97.5% g t1/2=2.6s g 178Au t1/2=10.8s ? 182Hg  = 101 a b+/EC 50 82 (15%) (85%) 2g9/2 t1/2=15.6s 1h9/2  = 81 t1/2=21.1s • KEY FEATURES • Decaydominatedbyselectionrule: • l = 1,0 • low-lyingnon-yrastcoexistingstates • E0 component of intrabandtransition 182Au 178Pt 3p1/2 3s1/2 2f5/2 2d3/2 3p3/2 3s1/2  1i13/2 = 6+, 7+or 3s1/2  1h9/2 = 4-, 5- or 3s1/2  3p3/2 = 1-, 2- 1h9/2  i13/2 = (2-, 11-) 1h11/2 1i13/2 2d5/2 1h9/2 1g7/2 2f7/2 ISOMERISM in 182Tl? E0 component 182Tl101 Probe shape-coexistence in 182Hg via -decay of 182Tl

  23. Si Annular Si pure 30 keVTl beam from RILIS+ISOLDE Intensity = 104pps C-foils 20mg/cm2 Si detectors -spectroscopy: Experimental Setup Windmill Chamber Ge detector #1 Annular Si Si ff a Courtesy of Thomas E. Cocolios 30 keV beam from ISOLDE ff C-foil Probe shape-coexistence in 182Hg via -decay of 182Tl

  24.  and Si- coincidences g1 g1 = 639 keV g2 or E0 g2 g1 E0 K-component 335KeV Si coincidenceswith 639 keV g1 - g2coincident: Gamma coincidenceswith 8+ 6+ (413.2 keV) Probe shape-coexistence in 182Hg via -decay of 182Tl

  25. Result: infer ground state of 182Tl g9/2 p1/2 f5/2 p3/2 s1/2  i13/2 = 6+, 7+or s1/2  h9/2 = 4-, 5- ors1/2  p3/2 = 1-, 2- i13/2 h9/2 f7/2 * * * * * * * h9/2 126 * 82 * * s1/2 * d3/2 h11/2 * d5/2 g7/2 * 50 82  = 81  = 101 [1] K.S. Bindraet al., Phys. Rev. C, 51 (1995) 401 Probe shape-coexistence in 182Hg via -decay of 182Tl

  26. Result: , and level mixing state: 973 keV - basedonunambiguouscoincidence relations - band-head of  vibrational band on top of prolate band - (621.9 keV): no E0 component state: 335 keV - identifiedbylooking at Si-gcoincidences - alreadyplaced at 328 (12) keVfrom-decay of 186Pb [1] - grayscoincidentwiththis Si energy: 639 keV state: 1124 keV - suggested in [2] but the 772.6 transitioncouldnotbeseen - from the energysystematics of the even-even Hg isotopes is a goodcandidatefor 4+member of the oblate band [2] M. Scheck et al., Phys. Rev. C, 81 (2010) 014319 [1] J.Wauters et al., Phys. Rev. C, 50 (1994) 2768 8+ 1358 (4+) 1124 772.6 576.6 (2+) 973 621.9 639 944 6+ 4+ 612 548 213 197 2+ 548 2+ 351 0+ 335 transition: 197 keV - important E0 component (ICC = = 4.2 (8)) - the twolevels are mixed; - the twolevels have different deformation 0+ 0 182Hg E0 Evidence for shape coexistence: transitions with E0 components are a model-independent signature of the mixing of configurations with different mean-square radii 180Hg, J.Elsevier et al., PRC 84, (2011) 034307 Probe shape-coexistence in 182Hg via -decay of 182Tl

  27. Down & Up Along the Nuclear Chart … a large world to explore Shape-coexistence 82 Although we have different experimental probes at our disposition, we still do not have a full picture of many phenomena N=40 50 126 28 82 50 Butnewpossibilitiesarise: ‐ multiple Coulomb Excitation ‐ transfer reactions ‐ spins, moments and radii measurements in previously hardly accessible regions

  28. IKS Leuven, Belgium - I. Stefanescu, J. Diriken, N. Bree, M. Huyse, O. Ivanov, J. Van de Walle, P. Van Duppen IPN Orsay, France - S. Franchoo CSNSM Orsay, France - G. Georgiev, E. Fiori, R. Lozeva IKP Köln, Germany A.Blashev, B.Bruyneel, J.Eberth, Ch.Fransen, K. Geibel, H.Hess, J.Jolie, M.Kalkuehler,P.Reiter, M.Seidlitz,N.Warr TU München, Germany - Th. Kröll, R. Krücken, K. Wimmer University of Camerino, Italy - D.L. Balabanski, K. Gladnishki, G. Lo Bianco, S. Nardelli Warsaw University, Poland - J. Iwanicki,  K. Hadynska,  K. Wrzosek,  M. Zielinska,  J. Srebrny University of Edimburg, Scotland – T. Davinson Universiteit Ghent, Belgium - K. Heyde, N. Smirnova CERN, Geneva, Switzerland -P. Delahaye, D. Fedorov, V. Fedosseev, U. Köster, B. A. Marsh, F. Wenander and the ISOLDE and MINIBALL collaborations Collaboration IKS Leuven, Belgium - I. Darby, J. Dirichen, J. Elseviers, N. Bree, M. Huyse, D. Pauwels, D. Radulov, P. Van de Bergh, P. Van Duppen University of West Scotland, UK – A.N. Andreyev, V. Liberati, Joe Comenius University, Bratislava, Slovakia - M. Venhart, S. Antalic, M. Veselsky, Zdenka University of Manchester, UK – I. Tsekhanovich University of Ioannina, Greece – N. Patronis Institute Laue Langevin, Grenoble, France - U. Köster CERN, Geneva, Switzerland – T. E. Cocolios, V. Fedoseev, B. A. Marsh, M. Seliverstov, Anatoly, Pavel Acknowledgement: Marie Curie Intra-European Fellowship of the EC’s FP7

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