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Experimental achievements and outlook (only a few examples to illustrate the achievements

Isotope Separator On-Line: In-Flight Separator:. ISOL. IF. Experimental achievements and outlook (only a few examples to illustrate the achievements and to paint the “road map” for the future). Extreme proton-to-neutron ratios Isospin as a degree of freedom (along N=Z)

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Experimental achievements and outlook (only a few examples to illustrate the achievements

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  1. Isotope Separator On-Line: • In-Flight Separator: ISOL IF Experimental achievements and outlook (only a few examples to illustrate the achievements and to paint the “road map” for the future) • Extreme proton-to-neutron ratios • Isospin as a degree of freedom (along N=Z) • The heaviest nuclei • High-spins and exotic excitations • Giant resonances in cold- and hot nuclei • Developments in instrumentation and facilities

  2. dC uncertainty budget dR = 0.5% ISOL Q T1/2 R dR <Ft> Extreme proton-to-neutron ratios: masses rp-process F. Hertfurth, ISOLTRAP, Hirschegg 2002 Super-allowed Fermi b-decay 74Rb (T1/2=65 ms) dm = 4.5 keV (dm/m = 6 10-8) ISOLDE

  3. IF Ch. Scheidenberger, GSI, Hirschegg 2002 238U fission • also at Mistral, SPEG (GANIL),... • mapping the mass surface • high-precision mass measurements on short-lived isotopes • nuclear structure, astrophysical scenarios, fundamental interactions • g.s. and i.s. properties (cfr. laser spectroscopy, e--RIB intersecting storage rings)

  4. 3.0 2.0 E (MeV) 1.0 ? oblate prolate 0.0 186Pb ISOL IF Extreme proton-to-neutron ratios: shapes, symmetries and low-lying excitations N = 126 N = 104 (midshell) 188Po 189Po 191Po Z = 82 decay and in-beam studies spherical Triple shape coexistence at low excitation energy Hartree-Fock + BCS (Skyrme SLy6 interaction + density dependent zero-range pairing force) (M. Bender, P.H. Heenen)

  5. 190Po 190Bi 191gBi 104 a g - RP - a 103 191Bi 188Bi Ea190Po decay DT(RP - a) < 10ms 190Po 191Po 188Bi 102 192Po Counts 10 6200 6400 6600 6800 7000 7200 7400 7600 IF Energy / keV Extreme proton-to-neutron ratios: shapes, symmetries and low-lying excitations Recoil Decay Tagging (RDT) RITU - JYFL Recoil Q D Q beam Decay Q target g-detectors PSSD Tagging 52Cr (255 MeV) + 142Nd 190Po + 4n s 160 nbarn !! 190Po

  6. REX-ISOLDE - CERN + MINIBALL array Neutron pick-up of 30Mg (T1/2=0.3 s) 30Mg + 2H 31Mg + 1H 10.000 atoms/sec 2.23 MeV/u 31Mg 16N (from beam contamination) ISOL E (keV) Extreme proton-to-neutron ratios: shapes, symmetries and low-lying excitations First results from SPIRAL and REX-ISOLDE SPIRAL - GANIL + EXOGAM array Coulomb excitation of 76Kr (T1/2=14.6 h) 76Kr + 48Ti 500.000 atoms/sec 2.6 - 4.4 MeV/u • decay- and RTD studies of exotic nuclei • Coulomb excitation and one- or two particle transfer reactions with energetic radioactive beams (e.g. around 132Sn and 100Sn - 78Ni, light Pb nuclei)

  7. ISOL IF Extreme proton-to-neutron ratios: unbound systems and the lightest nuclei Position of the neutron drip line: one extra proton added to the closed Z=8 shell binds 6 extra neutrons! one-proton halo 8 • complete kinematics: 6He, 11Li • p-elastic scattering @ relativistic energies • ... • in-beam gamma spectroscopy 20 31F 24O Z 2 one-neutron halo 8 2 N two-neutron halo four-neutron halo N=8 N=2 Z=2 3He 4He 5He 6He 7He 8He 9He 10He 3H 2H 1H 1n

  8. IF Extreme proton-to-neutron ratios: unbound systems and the lightest nuclei In-beam gamma-ray spectroscopy Sn=3.34(23) MeV wedge 24F, 25,26Ne, 27,28Na, 29,30Mg 2+-0+ Counts thick target 20C SISSI target 36S SPEG spectrometer Gamma-ray detectors E(keV) • high intensity beam (36S at 77.5 MeV/A, I  500pnA) • thick target 216 mg/cm2 of C and H • low counting rate in gamma-ray detectors 7000 C 6000 O 5000 Energy 2+ (keV) 4000 24O 3000 2000 20C M. Lewitowicz Hirschegg 2002 1000 4 6 8 10 12 14 16 18 closed shell N

  9. Q2p =1.14 MeV T1/2 =3.8 ms IF Extreme proton-to-neutron ratios: unbound systems and the lightest nuclei Two-proton decay of 45Fe 22 events • study of neutron skin nuclei, halo nuclei • confirmation of two-proton decay, correlations, map the proton drip line • clustering phenomena in unstable nuclei • increased intensity and beam purity of the second generation facilities is needed GANIL GSI

  10. Isospin as a degree of freedom • isospin symmetry and mirror pairs (extended to heavier masses along the N=Z line): • changes in collectivity: strong overlap between p- and n-wave function along the N=Z line • proton-neutron pairing: T=1 versus T=0 LNL - Legnaro Gammashpere • direct reactions with RIB • high-intensity stable beams and instrumentation (cfr. AGATA) quenching of p-n pairing field in neighboring NZ nuclei?

  11. IF The heaviest elements 1996 • confirmation element Z=112 (GSI) • chemistry Hs (Z=108) (GSI) • new results from Dubna tentatively assigned to Z=114, 116, 118 • gamma- and electron spectroscopy around 245No (e.g. RITU-JYFL) 2000 2001 • n-rich RIB on n-rich targets: reach region where decay chain from Z=114, 116,... ends • exploration of the structure of the trans-uranium nuclei • high intensity stable beams, new spectrometers and detectors electron spectrum from 245No (Z=102)

  12. 143Eu 143Eu SD ND SD ND The highest spin and exotic excitations • Euroball (Legnaro and Strasbourg) Gammasphere • giant dipole resonances on super deformed states • “wobbling mode”: breaking of axial symmetry • magnetic rotation • spontaneous chiral symmetry breaking • Rising at GSI • search for hyperdeformed states • need for intense stable beams • gamma-ray tracking (cfr. AGATA)

  13. IF Giant resonances in cold- and hot nuclei • Strength, centroid energy and width: governed by macroscopic nuclear properties (isoscalar - isovector modes) • Microscopically: coherent 1p-1h excitations / properties depend on the isoscalar and isospin dependence of the effective n-n interaction 16O real photons • Neutron-skin thickness can be deduced from Giant resonances (so far stable isotopes only) • Large proton-neutron asymmetry (exotic nuclei) can lead to “soft” collective resonances 20O virtual photons from 500-600 MeV/u 20,22O on Pb 22O • Photo-neutron cross sections for 16, 20, 22O • s(g,xn) strongly fragmented/extended to low energy • impact on astrophysical scenarios GSI • study the bulk properties of p-n asymmetry in nuclear matter (exotic nuclei): e.g. n-skin thickness • high-quality data with (d, 2He), (3He,t),... combined with large scale shell model calculations • elastic- and inelastic electron scattering, scattering on light nuclei and transfer reactions using RIB (intersecting storage rings)

  14. ISOL IF Instrumentation and facilities • ISOL and IF are complementary • Experimental aim of the second generation facilities •  figure of merit for the study of exotic nuclei x > 1000 • Technological challenge • increase the global selectivity and sensitivity • increase the secondary beam intensity • target-ion source developments • (e.g. laser ionisation,...) • spectrometer developments • detector developments • (e.g. AGATA, ...) • accelerator developments • target and ion source developments

  15. EURISOL European Separator On-Line Radioactive Nuclear Beam Facility GSI ISOL IF Instrumentation and facilities TSL-Uppsala KVI-Groningen JYFL-Jyväskylä CRC-Louvain-la-Neuve FZJ-Jülich GANIL-Caen GSI-Darmstadt ISOLDE - CERN LNL-Legnaro Oak-Ridge, MSU, Triumf and RIA (North-America) RIKEN (Japan) Radioactive Beam Factory ECT*-Trento

  16. Conclusion and recommendations • The last 5 years have witnessed important advances in technical developments and in the understanding of the atomic nucleus. Key issues, that should be addressed, have been identified. • Stable-beam experiments have been the driving force for many decades of nuclear-structure research. This limit of some 300 different beams will be overcome by the second generation radioactive beam facilities and a major part of the chart of nuclei will be available for tailored experiments. • Exotic nuclei are indeed a very selective probe (N/Z variation, neutron skins, coupling to the continuum,...) and the planned developments will bring new, accurate and unique information. • Vigorous exploitation of the existing accelerators and instrumentation (including upgrades) • physics results • R&D for beam production and detector systems • experimental capabilities for the coming 5 to 10 years • Full support for the new GSI accelerator complex and for the EURISOL project • ISOL and IF facilities are both needed (complementary aspects) • the new GSI accelerator complex: full support and start construction • EURISOL: next 5 years full conceptual design should be made and site determined, start construction at the end of this period • multi-users aspect should be incorporated • Very strong support for rebuilding nuclear-structure and nuclear-reaction theory efforts • provisions for new theoretical groups and expansion of existing groups • support for ECT* maintained and expanded • Communicate the highlights to society

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