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 <

The exploration of the chart of nuclei < Reactors: n on U

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

The exploration of the chart of nuclei < Selective detection method:  decay

The exploration of the chart of nuclei < Light-ion induced spallation Heavy-ion induced fusion

The exploration of the chart of nuclei < Projectile and target fragmentation + In-flight separation

The present chart of nuclei stable  + decay  - decay  decay p decay spontaneous fission Around 3000 of the expected 6000 nuclei have been observed -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

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

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

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

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

Louvain-la-Neuve: nuclear physics c.m.c.m. d  /d  (mb/sr) 4 He( 6 He, 6 He) 4 He E c.m. = 11.6 MeV 6 He U 4 He U 6 Li U 4 He U 6 He U fusion-fission 6 He + 4 He elastic scattering J. L. Sida et al. PRL84 (2000) 2342R. Raabe et al. PLB458 (1999) 1

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

Mass measurements rp-process Super-allowed Fermi  -decay 74 Rb (T 1/2 =65 ms)  m = 4.5 keV (  m/m = )

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

RIA expected yields A= Ni RIA expected yields 78 Ni: 70 at/s 100 Sn: 8 at/s Intensity and Selectivity

 secondary =  production  N target  beam x  release – transport x  ionization x  transport - storage - post-acceleration I secondary /I total Intensity Purity Event rate I counts (reaction) = I secondary  branching  reaction N secondary target x  spectrometer x  detector I counts (decay) = I secondary  branching x  detector Peak to background R resolving power (suppression of background, identification of events) Figures of Merit (in first approximation)

MeV/u E x ( ) = 4 MeV B(E2)=500 e 2 fm 4  (Coulex)  100 mb N secondatytarget (58 Ni) = 3mg/cm2 N target ( 238 U,  = 100 pbarn) = 100 g/cm 2 Countrate estimate“Ideal (realistic?)” I counts ( ) (minimum) 10 cts/day   x  spectrometer 10 % I secondary ( 78 Ni)375 at/s  post-accelerator 50 %  ionization 50 %  release 50 % I beam (p, 1 GeV)19  A needed!! needs pure conditions modest intensity! An example: Coulomb excitation of 78 Ni at an ISOL system

“Ideal (realistic?)”NowGain factor I beam (p, 1 GeV)100  A direct (5000  A indirect) 10  A10 (> 500)  release 50 %0.1 %500  ionization 50 %10 %5  post-accelerator 50 %10 %5 I secondary ( 78 Ni)2000 at/s58 at/h 10 5   x  spectrometer 10 %1 %10  10 4 beam purity? 78 Ni produced at an ISOL system: rates

Now (1) ProposedGain factor I beam ( 238 U, 1 GeV/u)10 10 at/s at/s100  in-flight separator % (  5%)30 – 60 % (  50%) (2) 10 I secondary ( 78 Ni)35 at/h10 at/s (3) 1000 (1) based on the first identification of 78 Ni C. Engelmann et al., Z. Phys. A352 (1995) 351 * I( 238 U) = at/s *  in-flight separator = 1.6% * I( 78 Ni) = 0.5 at/day (2) GSI: Conceptual Design Report (3) RIA: I( 238 U) = MeV/u I( 78 Ni) = 70 at/s ! ! ! N sec. target (IF) = 100 x (ISOL) but Low energy background and Doppler correction 78 Ni produced at an IF system: rates

Stopping of fragments in a gas cell (I) 100 cm 30 cm 0.5 – 1 bar Delay (ms) Argon Helium E/N ( V. cm 2 ) G. ANL Heavy-Ion Beam High-power target Range bunching Gas catcher Low energy beam range bunching stopping of reaction products in buffer gas electrical fields (AC and DC) remove electrons (neutralization) drag ions towards exit hole

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

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

 -decay of 78 Cu at ISOLDE 78 Ni  0.2 s 78 Cu 0.34 s 78 Zn 1.5 s 78 Ga 5.5 s 78 Ge 88 m 78 As 1.5 h 78 Se N=50 Z=28 1  10 2  10 4  relative J.M. Daugas et al. Phys. Lett. B476 (2000) (2 + ) (8 + ) (6 + ) (4 + ) 78 Zn 908 keV 890 keV 730 keV p(1 GeV) + Ta-rod  neutron neutron U  78 Cu  no deep spallation The problem of selectivity: an example from ISOL

laser ionization of Cu isotopes  -gated gamma decay spectrum Energy (keV) Ga 78 Cu 730 keV 890 keV laser on laser off Energy (keV) Production rates: J.M. Daugas et al. Phys. Lett. B476 (2000) (2 + ) (8 + ) (6 + ) (4 + ) 78 Zn 908 keV 890 keV 730 keV The decay of 78 Cu

(1 + ) (3 - ) (6 - ) 70 Cu (2) s 33(2) s 44.5(2) s (keV)  V. Fedoseev, U. Koster, J. Van Roosbroeck et al., ISOLDE laser ionization in a hot cavity different hyperfine splitting for the different isomers enhancement of specific isomers increase selectivity of laser ion sources reduce power, pressure and Doppler broadening Production of isomeric beams: 70 Cu m1,m2,g

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