Spectroscopy of exotic nuclei Lecture 1 Reiner Krücken Physik Department E12 Technische Universität München Maier-Leibnitz Laboratory of TU München and LMU München for Nuclear-, Particle-, and Accelerator Physics R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Outline Introduction –Central questions of the Physics of Exotic Nuclei –Production of radioactive ion beams Selected Topics in the Physics of Exotic Nuclei –Nuclear Shell Structure and its Modifications in Exotic nuclei –Halos, Skins and Pygmy Resonances –Superheavy Nuclei –Shape coexistence Aim of the lectures: Discussion of current physics questions in combination with an introduction to various experimental methods R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1 2

From QCD to atomic nuclei uu d Quarks, Gluons nucleon-nucleon interaction (ab-initio Models) Light nuclei (A  10) ? QCD Protons, Neutrons R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 13

Ab-initio calculations of light nuclei R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture CPU hours

From QCD to atomic nuclei uu d Quarks, Gluons nucleon-nucleon interaction (ab-initio Models) Light nuclei (A  10) ? ? Heavy nuclei effective nucleon-nucleon interaction (Mean-field theories) QCD Protons, Neutrons R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 15

The Nuclear Landscape Source: NUCLEUS A Trip Into The Heart of Matter 6R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Bethe and von Weizäcker Volume energy Surface energy Coulomb energy Asymmetry energy Pairing energy Binding Energy Coefficients a v = MeV a s = MeV a c = MeV a A = Mev a P = 12.0 MeV Semi-empirical mass formula R = r 0 A 1/3 Volume Volume + Surface Volume + Surface + Coulomb Volume + Surface + Coulomb + Asymmetry B/A (MeV/nucleon) Mass number A 7R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Binding energy per nucleon Saturation of binding due to short range of NN interaction Maximal binding around Fe  Synthesis up to Fe via fusion in stars  heavy elements are produced differently (n-capture)  Fission and alpha decay are possible 8R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Shell effects in the binding energies 9 M exp – M Weizsäcker ? ? R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Shell structure in nuclei and metal clusters Annu. Rev. Nucl. Part. Sci. 2001, Vol. 51: H.O. + L 2 + LS S.G. Frauendorf, C. Guet 10R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

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 11R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Valley of stability & the limits of stability Energy 12R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

r-process and shell structure Nuclear shell structure - Defines r-process path - Imprinted in abundance pattern - maybe modified for exotic nuclei -Fission may fill the holes -Depends on shell structure r - process G. Martinez-Pinedo et al. Pfeiffer et al. element number abundance log(X/H)-12 CS (Sneden et al. 2003) solar r 13R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Production of radioactive ion beams R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 114

How to produce and study Exotic Nuclei 15 Spectroscopic Methods:  - ray and particle spectroscopy following Decay spectroscopy Coulomb excitation One- and Multi-nucleon transfer knockout-reactions Secondary fragmentation Production of radioactive ion beams: in-flight production Isotope Separation On-Line What can be measured? existence of nuclei masses, radii, half-lives Excited states: energies, quantum numbers, transition matrix elements, lifetimes, moments, single-particle occupations... R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Production of radioactive ion beams Isotope Separation On-Line Diffusion from thick target - depends on chemistry - Needs time Fragments move with beam velocity (30-90% c) Reaction induced by light projectile (p,d,n) in thick target Exotic nuclei are produced in thin target as fragment of heavy beam 16R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1 In-flight separation

R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1 In-flight production of radioactive beams 17 Projectile fragmentation or fission at high energies ( AMeV) Both fragments are highly excited ad evaporate nucleons Fig. by T. Glasmacher (NSCL/MSU)

B  -  E - B  Separation Method 18R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

UNILAC SIS FRS ESR 100 m Fragment Identification EE EE TOF 19R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

FAIR: Facility for Antiproton and Ion Research R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 120 Primary Beams /s; GeV/u; 238 U 28+ Factor over present in intensity Secondary Beams Broad range of radioactive beams up to GeV/u; up to factor in intensity over present Antiprotons GeV Storage and Cooler Rings Radioactive beams e - - A and Antiproton-A collider 100 m UNILAC SIS 18 SIS 100/300 HESR Super FRS NESR CR RESR GSI today Future Facility ESR

1.4 GeV ISOLDE at CERN from PS Booster 21R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

REX-ISOLDE R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 122

FRIB in the U.S. (MSU/NSCL) R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 123

Modifications of nuclear shell structure R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 124

Two-neutron separation energies R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 125 Fig. by R.F. Casten Shell closure

The extreme single-particle model R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 126 Strong Spin-orbit From individual nuclei with NN interaction to mean field with residual interaction

Penning Trap Mass Measurements Ingredients: –Homogeneous vertical magnetic field  Radial trapping  cyclotron motion:  c = B q/m –Axial electrostatic quadrupole field  Vertical trapping  Vertical oscillation:  z =(qU 0 /(md 2 )) 1/2 modified cyclotron motion: 4d 2 =(2z 0 2 +r 0 2 ) magnetron frequency: 27R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Penning Trap Mass Measurements Coupling between modes  conversion to cyclotron motion Excite cyclotron motion via quadrupole RF Eject ions along trap axis  transform radial energy to axial energy via dB/dz gradient Measure time of flight (TOF) -the shorter TOF, the closer is the excitation frequency to the resonance K. Blaum, Physics Reports 425 (2006) 1 – 78 28R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

ISOLTRAP A. Herlert, et al., Int. J. Mass Spectrom. 251, (2006) 131 bunching measurement purification 29R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 1

Backup R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 130

Nuclei - towards a unified theoretical framework V low-k, V UCOM (+3N) AV18, CD Bonn + 3N  EFT Greens Function Monte Carlo No Core Shell Model Coupled Cluster Large Scale Shell Model Density Functional Theory Relativistic Mean Field Theory R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 131

Other in-flight facilities (incomplete) R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 132 National Coupled Cyclotron Facility Michigan State University Radioactive Ion Beam Factory at RIKEN, Tokyo

Other ISOL facilities (incomplete) R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 133 ISAC at TRIUMF, Vancouver, Canada SPIRAL2 at GANIL, Caen, France HRIBF at ORNL Oak Ridge, USA

Indications of 24 O magic shell closure R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 134 A. Ozawa et al., PRL 84, 5493 (2000) N-Z=1 N-Z=5 N-Z=9 N-Z=0 N-Z=2... what is the heaviest bound oxygen isotope???? Oxygen(Z=8) unbound bound

Shell structure far from stability R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 135

Single-particle levels in O isotopes R. Krücken - XVth UK Postgraduate School in Nuclear Physics – Lecture 136 Otsuka et al., arXiv: v1 [nucl-th] Large gap for N=16  24 O new doubly magic nucleus