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Spectroscopy of exotic nuclei

Spectroscopy of exotic nuclei. Reiner Krücken Physik Department E12 Technische Universität München Maier-Leibnitz Laboratory of TU München and LMU München for Nuclear -, Particle -, and Accelerator Physics. From QCD to atomic nuclei. d. u. u. Protons, Neutrons. Quarks, Gluons.

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Spectroscopy of exotic nuclei

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  1. Spectroscopyofexoticnuclei Reiner Krücken Physik Department E12 Technische Universität München Maier-Leibnitz Laboratory of TU München and LMU München forNuclear-, Particle-, andAcceleratorPhysics

  2. From QCD to atomic nuclei d u u Protons, Neutrons Quarks, Gluons Light nuclei (A10) ? QCD nucleon-nucleon interaction (ab-initio Models)

  3. Ab-initio calculations of light nuclei 7500 CPU hours

  4. From QCD to atomic nuclei d u u Protons, Neutrons Quarks, Gluons Light nuclei (A10) ? ? QCD Heavy nuclei nucleon-nucleon interaction (ab-initio Models) effective nucleon-nucleon interaction (Mean-field theories)

  5. Shell structure in nucleiandmetalclusters 198 184 168 138 126 112 92 82 70 58 50 40 40 28 20 20 20 8 8 8 2 2 2 H.O. + L2 + L•S S.G. Frauendorf, C. Guet Annu. Rev. Nucl. Part. Sci. 2001 , Vol. 51: 219-259.

  6. Central Questions in Nuclear Structure Physics • Where are the limits of nuclear stability? • How does shell structure change far from stability? • What are the phases, relevant degrees of freedom, and symmetries of the nuclear many-body system? • Are there new modes of collective excitation? • How are the Heavy Elements produced? • Unified theoretical framework • with predictive power Diversified experimental strategy to understand the Structure and Dynamics of Exotic Nuclei: • Measure Ground State Properties • Gamma-ray spectroscopy of excited states • Reaction studies

  7. r-process and shell structure CS22892-052 (Sneden et al. 2003) solar r abundance log(X/H)-12 element number • Nuclear shell structure • Defines r-process path • Imprinted in abundance pattern • maybe modified for exotic nuclei Pfeiffer et al. r - process • Fission may fill the holes • Depends on shell structure G. Martinez-Pinedo et al.

  8. Production of radioactive ion beams

  9. Production of radioactive ion beams In-flightseparation Isotope Separation On-Line Exotic nuclei are produced in thin target as fragment of heavy beam Reaction induced by light projectile (p,d,n) in thick target • Diffusion from thick target • depends on chemistry • - Needs time Fragments move with beam velocity (30-90% c)

  10. In-flight production of radioactive beams Projectile fragmentation or fission at high energies (50 -1000 AMeV) Both fragments are highly excited ad evaporate nucleons Fig. by T. Glasmacher (NSCL/MSU)

  11. Br - DE - Br Separation Method

  12. Fragment Identification DE DE TOF SIS FRS UNILAC ESR 100 m

  13. FAIR: Facility for Antiproton and Ion Research Primary Beams • 1012/s; 1.5-2 GeV/u; 238U28+ • Factor 100-1000 over present in intensity Secondary Beams Storage and Cooler Rings • Broad range of radioactive beams • up to 1.5 - 2 GeV/u; • up to factor 10 000 in intensity over present • Antiprotons 3 - 30 GeV • Radioactive beams • e- - A and Antiproton-A collider Future Facility SIS 100/300 GSI today SIS 18 UNILAC ESR 100 m HESR Super FRS RESR CR NESR

  14. ISOLDE at CERN 1.4 GeV from PS Booster

  15. REX-ISOLDE

  16. Modifications of nuclear shell structure

  17. Two-neutron separation energies Shell closure Fig. by R.F. Casten

  18. The extreme single-particle model Strong Spin-orbit From individual nuclei with NN interaction to mean field with residual interaction

  19. Probing shell closures: Decay Spectroscopy N=82 b-decay Q-value (ISOLDE):  130Cd less bound  Quenching of N=82 shell ? I. Dillmann, PRL91 (2003) 162503 • no shell quenching • information on excited states essential!! A. Jungclaus et al., PRL 99, 132501 (2007)

  20. SIMBA Implantation Detector in RISING Ch. Hinke, K. Eppinger, K. Steiger

  21. Shell modification through softer potential Pfeiffer et al. T.R. Werner, J. Dobaczewski, W. Nazarewicz, Z. Phys. A358 (1997) 169 Possible signatures:  new shell gaps (e.g. N=70 in 110Zr)  reduction of spin-orbit splitting in neutron-rich nuclei  increased neutron skin

  22. Shell modification through residual interaction Effective single particle energies N=20 unbound bound 24O doubly magic 32Mg deformed T. Otsuka et al. Z=8 O. Sorlin, M.G. Porquet, Prog. Part. Nucl. Phys. 2008 ... whatistheheaviestboundoxygen isotope????

  23. Non-existence of 28O (Z=8,N=20) H. Sakurai et al., Physics Letters B 448 (1999) 180 RIPS@RIKEN Position x-y ètrajectoryBrèp, A/Z TOF èv èA dE/dxèZ

  24. The neutron drip-line O  F: 1 extra proton can bind 6 more neutrons Is 24O doubly magic? Otsuka et al., arXiv:0908.2607v1 [nucl-th]

  25. 24O knock-out experimentatthe GSI FRS FRS operation in 'dispersion matched mode' → direct momentum measurement at S4 6.347 g/cm2 Be 48Ca 1A GeV Excellent agreement with predictions for N=16 shell closure carbon 4.05 g/cm2 R. Kanungo et al., PRL 102 (2009) 152501

  26. Reduced spin-orbit or tensor force? j’> j’< j> neutrons j< protons T. Otsuka et al., PRL 95 (2005) 232502 11/2- 7/2+ 1h11/2 protons 1g7/2 protons Z=51 Sb isotopes J.P. Schiffer et al., PRL 92 (2004) FRIB 1h11/2 neutrons T. Otsuka et al., PRL 97 (2006) 162501

  27. Intermediate energy Coulomb excitation T. Glasmacher, Annu. Rev. Nucl. Part. Sci. 1998.48:1-31 Doppler-correction Au 40S 20-50 MeV/u Au • Possible complications: • a) Need to separate EM interaction from nuclear interaction • select small scattering angles  large distance between nuclei • b) Possible feeding from higher lying 2+ states

  28. Collectivity of 32,34Mg T. Motobayashi et al. Phys. Lett. B 346 (1995) 9. K. Yoneda et al., Phys. Lett. B 499 (2001) 233 150 Without N=20 shell N=20 100 B(E2; 2+ 0+) [e2fm4] 50 With N=20 shell 0 30 32 38 36 34 Ar S Si Mg Ne 32Mg: E(4+)/E(2+) = 2.6 34Mg: E(4+)/E(2+) = 3.2 Rotor: E(4+)/E(2+) = 10/3 Secondary fragmentation of 36Si beam

  29. Transfer reactions • (d,p), (3He,d): Stripping of neutron or proton from light ion • (p,d), (3He,a): Pick-up of neutron/proton by light ion • Example • d + 90Zr  p + 91Zr or90Zr (d,p) 91Zr Other examples:(d,p), (a,3He)…(p,d), (3He, a)…(3He, d), (a, t)…(d,3he), (t,a)…

  30. Example– 54Fe(d,p)55Fe Munich Q3D 25 MeV deuterons 5 keV FWHM counts 55Fe Energy (keV)

  31. Transfer set-up T-REX inside MINIBALL efficiency of full 4p array: 62% • T-REX position sensitive silicon detector array: • forward barrel (DE-E): 140/1000 μm • backward barrel/CD: 500 μm silicon • 3◦ − 5◦ angular resolution • energy resolution of 60 keV (backward) to 2 MeV (forward) at 3 MeV/u V. Bildstein, K. Wimmer

  32. Modification of shell structure Ti 46 48 49 50 47 Sc 45 classic shell closures Ca 43 40 42 44 46 48 54 Predicted new shell closures K 39 41 Ar 36 38 40 Cl 35 51 37 S 32 33 34 36 P 31 47 Si 28 29 30 44 Al 27 43 Mg 24 25 26 32 40 Na 23 36 20 21 22 34 Ne 19 31 F Island of inversion 18 24 O deformed g.s.

  33.  probe bulk properties of nuclei symmetry energy compressibility effective NN interaction Giant resonances Radioactive beams allow to study isospin dependence of nuclear bulk properties New Phenomenon:  Soft Modes

  34. Dipole Excitations of Neutron-Rich Nuclei Photoabsorption LAND collaboration A. Klimkiewicz, PRCL subm. P. Adrich, PRL 95 (2005) 124Sn Coulomb excitation 130Sn P. Ring et al. 132Sn neutron skin  core vibration

  35. Symmetry Energy, EOS and Neutron Stars Expansion of energy per nucleon around saturation density 0 Symmetry energy a4 = Symmetry energy in neutron matter (asymmetry parameter) RQRPA Pygmy strength N. Paar

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