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Radioactive Ion Beams: where are we now experimentally? M. Huyse K.U. Leuven Moriond, March 2003. Opening page. The exploration of the chart of nuclei. 284 isotopes with T 1/2 > 10 9 year Our beams till 1989 !. The exploration of the chart of nuclei. <1940 495.

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  1. Radioactive Ion Beams: where are we now experimentally? M. Huyse K.U. Leuven Moriond, March 2003 Opening page

  2. The exploration of the chart of nuclei 284 isotopes with T1/2 > 109 year Our beams till 1989 !

  3. The exploration of the chart of nuclei <1940 495

  4. The exploration of the chart of nuclei Reactors: n on U <1940 1940 495 822

  5. The exploration of the chart of nuclei First Isotope Separator On-Line (ISOL) experiment Niels Bohr Institute 1951 fast n on U: Kr and Rb isotopes <1940 1940 1950 495 822 1244

  6. The exploration of the chart of nuclei Selective detection method:  decay <1940 1940 1950 1960 495 822 1244 1515

  7. The exploration of the chart of nuclei Light-ion induced spallation Heavy-ion induced fusion <1940 1940 1950 1960 1970 495 822 1244 1515 2010

  8. The exploration of the chart of nuclei Projectile and target fragmentation + In-flight separation <1940 1940 1950 1960 1970 1980 495 822 1244 1515 2010 2270

  9. The present chart of nuclei • stable + decay • - decay  decay p decay spontaneous fission • -Explaining complex nuclei from basic constituents • -The size of the nucleus: halos and skins • -Isospin dependence of the nuclear force • Measuring and predicting the limits of nuclear existence • Doubly-magic nuclei and shell structure far from stability • The end of Mendeleev’s table: superheavies • Understanding the origin of elements • Testing the Standard Model • Applications in materials and life sciences Around 3000 of the expected 6000 nuclei have been observed

  10. In Flight (IF) Isotope Separator On Line (ISOL) gas cell ~ ms storage ring post accelerator meV to 100 MeV/u ms to several s good beam quality driver accelerator or reactor • heavy ions • fusion • fragmentation • light and heavy ions, n, e • -spallation • -fission • fusion • fragmentation IF versus ISOL thin target high-temperature thick target ion source fragment separator mass separator GeV eventually slowed down ms • experiment • detectors • spectrometers • ...

  11. First generation Radioactive Beam Projects in Europe CRC, Louvain-la-Neuve, Belgium delivering ISOL beams since 1989 GSI, Darmstadt, Germany delivering IF beams since 1990 SPIRAL, Caen, France delivering IF beams since 1984 delivering ISOL beams since 2001 MAFF, Munich, Germany under construction REX-ISOLDE, Geneva, Switzerland delivering ISOL beams since 2001 SPES, Legnaro, Italy project

  12. Location Start Driver Post-accelerator Upgrade planned CRC, Louvain-la-Neuve, Belgium 1989 cyclotron p, 30 MeV, 200A cyclotrons K = 44 and 110 SPIRAL, GANIL, Caen, France 2001 2 cyclotrons heavy ions up to 95 MeV/u 6 kW cyclotron K = 265 2 - 25 MeV/u new driver REX-ISOLDE, CERN, Geneva, Switzerland 2001 PS booster p, 1.4 GeV, 2 A linac 0.8 - 2.2 MeV/u energy upgrade 4.3 MeV/u HRIBF, Oak Ridge, USA 1998 cyclotron p, d, , 50 -100 MeV 10 - 20 A 25 MV tandem ISAC, TRIUMF, Vancoucer, Canada 2000 synchrotron p, 500 MeV, 100 A linac 1.5 MeV/u energy upgrade 6.5 MeV/u First generation Radioactive Beam Projects

  13. Louvain-la-Neuve: focus on nuclear astrophysics CYCLONE 110 30 MeV p + 13C => 13N + n 13N + p => 14O +  Hot CNO cycle

  14. Louvain-la-Neuve: nuclear physics • ds/dW (mb/sr) • 4He(6He,6He)4He • Ec.m. = 11.6 MeV 6He + 238U 4He + 238U 6Li + 238U 4He + 238U • qc.m. 6He + 238U fusion-fission 6He + 4He elastic scattering J. L. Sida et al. PRL84 (2000) 2342 R. Raabe et al. PLB458 (1999) 1

  15. First results from SPIRAL and REX-ISOLDE E (keV) SPIRAL - GANIL + EXOGAM array REX-ISOLDE - CERN + MINIBALL array Coulomb excitation of 76Kr (T1/2=14.6 h) Neutron pick-up of 30Mg (T1/2=0.3 s) 76Kr + 208Pb 500.000 atoms/sec 2.6 - 4.4 MeV/u 30Mg + 2H 31Mg + 1H 10.000 atoms/sec 2.23 MeV/u 31Mg 16N (from beam contamination)

  16. Mass measurements rp-process Super-allowed Fermi b-decay 74Rb (T1/2=65 ms) dm = 4.5 keV (dm/m = 6 10-8)

  17. EURISOL European Separator On-Line Radioactive Nuclear Beam Facility Rare Isotope Accelerator: RIA GSI RI-Beam factory: RIKEN The new generation of Radioactive Beam Facilities • 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

  18. Intensity and Selectivity RIA expected yields 77 76 79 80 78Ni A=78 RIA expected yields Intensity 100Sn: 8 at/s 78Ni: 70 at/s Selectivity

  19. Figures of Merit (in first approximation) Isecondary = sproductionNtarget Ibeam x erelease – transport x eionization x etransport - storage - post-acceleration Intensity Intensity Icounts(reaction) = Isecondary hbranchingsreaction Nsecondary target x espectrometer x edetector Icounts(decay) = Isecondary hbranching x edetector Sensitivity Event rate Selectivity Isecondary/Itotal Purity Rresolving power (suppression of background, identification of events) Peak to background

  20. An example: Coulomb excitation of 78Ni at an ISOL system 78Ni @ 3-5 MeV/u Ex(2+-0+) = 4 MeV B(E2)=500 e2fm4 s(Coulex)  100 mb Nsecondatytarget (58Ni)= 3mg/cm2 Ntarget (238U, s = 100 pbarn) = 100 g/cm2 needs pure conditions modest intensity!

  21. 78Ni produced at an ISOL system: rates  104 beam purity?

  22. 78Ni produced at an IF system: rates ! ! ! Nsec. target (IF) = 100 x (ISOL) but Low energy background and Doppler correction • (1) based on the first identification of 78Ni • C. Engelmann et al., Z. Phys. A352 (1995) 351 • I(238U) = 2 107 at/s • ein-flight separator= 1.6% • I(78Ni) = 0.5 at/day • (2) GSI: Conceptual Design Report • (3) RIA: I(238U) = 2 1013 at/s @ 400 MeV/u I(78Ni) = 70 at/s

  23. 100 cm Delay (ms) 1000 100 10 1 0.1 30 cm 0.5 – 1 bar Argon Helium G. Savard @ ANL 0.01 0.1 1 10 E/N (10-17 V . cm2) Stopping of fragments in a gas cell (I) Heavy-Ion Beam • range bunching • stopping of reaction products in buffer gas • electrical fields (AC and DC) • remove electrons (neutralization) • drag ions towards exit hole High-power target Range bunching Gas catcher Low energy beam

  24. laser Stopping of fragments in a gas cell (II) • what is the intensity limit? heavy-ion ion guide M. Huyse,- Nucl. Instr. Meth. B Fragmentation G. Savard ,- @ ANL and GSI G. Bollen ,- @ MSU M. Wada ,- @ RIKEN 1 RIA fission ion guide 2 5 Shiptrap 4 He (1 atm) 3 RADRIS • laser ionization after the plasma has decayed • increased selectivity!

  25. Laser Ion Source Energy (eV) 4 0 Laser ion source at ISOLDE • efficiency up to 10 % • selectivity: depending on the implementation • applicable for many elements (universal) surface ions photo ions + + laser + + + high-temperature cavity

  26. The problem of selectivity: an example from ISOL 78Se (8+) (6+) 908 keV (4+) 78Cu 0.34 s 78Ni 0.2 s 78Ge 88 m 78As 1.5 h 78Zn 1.5 s 78Ga 5.5 s 890 keV (2+) 1 730 keV 0+ 78Zn J.M. Daugas et al. Phys. Lett. B476 (2000) 213 • b-decay of 78Cu at ISOLDE • p(1 GeV) + Ta-rod  neutron • neutron + 238U 78Cu •  no deep spallation 104 srelative 102 N=50 laser ionization of Cu Z=28

  27. The decay of 78Cu 730 keV 890 keV (8+) laser on (6+) 105 104 103 78Ga 78Cu 908 keV (4+) 890 keV laser off (2+) 700 800 900 730 keV Energy (keV) 0+ 78Zn J.M. Daugas et al. Phys. Lett. B476 (2000) 213 600 700 800 900 1000 Energy (keV) • laser ionization of Cu isotopes • b-gated gamma decay spectrum Production rates:

  28. Production of isomeric beams: 70Cum1,m2,g (keV) (1+) 6.6(2) s b 200 (3-) 33(2) s 100 44.5(2) s (6-) 0 70Cu41 29 • laser ionization in a hot cavity • different hyperfine splitting for the different isomers • enhancement of specific isomers V. Fedoseev, U. Koster, J. Van Roosbroeck et al., ISOLDE • increase selectivity of laser ion sources • reduce power, pressure and Doppler broadening

  29. Outlook • high-power accelerators • high-power targets • geometrical optimization • radiation safety production • laser ionization (selectivity, isomeric beams) • release optimization, chemistry • gas cell (space-charge limit, laser re-ionization) • charge-state breeding vs. 1+ acceleration ionization • RF-coolers, traps • (intensity limit, high-resolution mass separator) purification acceleration / deceleration / storage • g-identification • fast tracking of particles • measurement: • identification • reaction / decay / g.s. properties • ...

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