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DESIR @ SPIRAL2

Laser spectroscopy studies at the DESIR facility of SPIRAL2. DESIR @ SPIRAL2. organi z ation & scientific program. layout of the facility. status and perspectives. Laser spectroscopy @ DESIR: the LUMIERE project. physics cases. experimental techniques. research program.

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DESIR @ SPIRAL2

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  1. Laser spectroscopy studies at the DESIR facility of SPIRAL2 • DESIR @ SPIRAL2 • organization & scientific program • layout of the facility • status and perspectives • Laser spectroscopy @ DESIR: the LUMIEREproject • physics cases • experimental techniques • research program J.C. Thomas – XVth Colloque GANIL, Giens 2006

  2. talk by A. Mery DESIR Désintégration, Excitation et Stockage d’Ions Radioactifs An open collaboration to promote ISOL beams at SPIRAL2 • Results from the SPIRAL2 workshop held at GANIL on July 2005 « Physics with low energy beams at SPIRAL2 » http://spiral2ws.ganil.fr/2005/lowenergy/program/presentations/ • Follows the earlier proposition of a low-energy RIB facility at SPIRAL - Promotors (1998): G. Auger, B. Blank, C. Le Brun, …. - LIRAT facility (2005): 6He, 19Ne, 32,35Ar @ ~ 30 keV

  3. DESIRorganization * spokes-person: B. Blank, blank@cenbg.in2p3.fr * GANIL correspondent: J.-C. Thomas, thomasjc@ganil.fr • Working groups / correspondents: - Beam handling and beam preparation / lunney@csnsm.in2p3.fr - Laser spectroscopy / leblanc@ipno.in2p3.fr - Decay spectroscopy / borge@iem.cfmac.csic.es • Links to SPIRAL2 project management: - Scientific program: M. Lewitowitcz - Installation: M.-H. Moscatello

  4. DESIRphysics program • Decay spectroscopy - decay properties and nuclear structure studies - particle-particle correlations, cluster emission, GT strength - exotic shapes, halo nuclei • Laser spectroscopy - static properties of nuclei in their ground and isomeric states - nuclear structure and deformation • Fundamental interactions - CVC hypothesis, CKM matrix unitarity via 0+ 0+ transitions - exotic interactions (scalar and tensor currents) - CP and T violation • Solid state physics and other applications

  5. TheDESIRfacility @ SPIRAL2 technical requirements • A new experimental area of about 1500m2 • Availability from day 1 • Run in parallel with post-accelerated beams Fast change of the mass setting Neutron-rich and neutron-deficient beams • More than one production station • Different target-ion source assemblies including a laser ionization source • Different production modes including fusion-evaporation and DI reactions • Use of isotopically separated beams • A high resolution mass separator with a resolution of M/M>5000 • Extension of the current LIRAT beam line

  6. TheDESIRfacility @ SPIRAL2 layout Production building DESIR LINAG GANIL facility LIRAT

  7. Production building LINAG GANIL Ident. Station HRS DESIR Exp. Area

  8. DESIR building - Underground GANIL facility today

  9. Spectroscopy of trapped beams Laser Spectroscopy this talk and P. Mueller talk by A. Herlert talk by M.J.G. Borge Decay studies Cooling/Bunching Other purposes Fundamental Interactions talk by P. Delahaye talks by A. Mery and N. Severijns DESIR building -Ground floor

  10. Status of theDESIRProject • DESIR building (new experimental area) • preliminary design study: B.Blank et al.,CEN Bordeaux-Gradignan • High resolution separator • preliminary design study: D. Lunney et al., CSNSM Orsay • Beam preparation (cooler) • O. Naviliat et al.,LPC Caen + D. Lunney et al.,CSNSM Orsay • Presentation of the DESIR Project to the IN2P3 SC in July 2006 • LoI to be submitted in October 2006 (Contact: B. Blank)

  11. Synergies with other facilities • ALTO: laser ionization source, laser spectroscopy • FAIR/NuSTAR: MATS, LASPEC, NCAP,DESPEC • RIKEN/RIBF: SLOWRI • Common issues • beam preparation using coolers and traps • low-energy beam diagnostics • new types of gamma and neutron detectors

  12. Towards DESIR: LIRAT extension • Multi-beam facility (physics program  2012) • Tests and development for SPIRAL2 & DESIR LIRAT today b Spec. LPC Trap Tests SPIRAL2 1+ n+

  13. collinear laser spectroscopy + b-NMR • double laser + RF spectroscopy in traps TheLUMIEREproject @ DESIR Laser Utilisation for Measurement and Ionization of Exotic Radiaoctive Elements Spokes-person: F. Le Blanc,leblanc@ipno.in2p3.fr Physics cases: • Nuclear structure and deformation studies far from stability, in the vicinity of closed shells • from systematic measurements of the static properties of exotic nuclei in their ground and isomeric states: <r²>, I, Qs, Ip • Hyperfine anomaly and high-order components of the hyperfine interaction • from precise measurements of the hyperfine structure constants

  14. Atomic hyperfine structure Interaction between an orbital e- (J) and the atomic nucleus (I,mI,QS) • results in a hyperfine splitting (HFS) of the e- energy levels n J with F DEHFS • Hyperfine structure constants: and • Collinear laser spectroscopy: DmI/mI ~ 10-2, DQS/QS ~ 10-1 for heavy elements

  15. Isotope shift measurements Frequency shift between atomic transitions in different isotopes of the same chemical element • related to the mass and size differences J2, F2 dnA,A’ J2, F2 J1, F1 J1, F1 • mean square charge radius variations with a precision ~ 10-3 • study of nuclei shape (deformation)

  16. COMPLIS • onset of deformation at N=82 (slope ↔ rigidity) • shape transition (even-odd staggering) • shape coexistence • dynamical effects (vibration) Isotope shift measurements • previous experiments: N~82 N~104

  17. Isotope shift measurements at DESIR • with I ~ 103-104 pps: • N~50: • neutron skin in N > 50 Ge isotopes (neutron star studies) • deformation in N ≤ 50 Ni isotopes (collectivity vs magicity) • N~82: • shape evolution for Z ≤ 50 (Ag, Cd, In, Sn) • N~64: • strongly oblate shapes predicted in Rb, Sr and Y for N > 64 • Z~40: • shape transitions predicted in the Zr region (Mo, Tc, Ru) • Rare earth elements: • large deformation and shape transitions predicted (Ba, Nd, Sm)

  18. B0 b-NMR spectroscopy b-asymmetry in the decay of polarized nuclei in a magnetic field • Zeeman splitting related to gI and QS M+I I M-I with and • resonant destruction of the polarization (i.e. b-asymmetry) by means of an additional RF magnetic field • DgI/gI ~ 10-3, DQS/QS ~ 10-2 • complementary technique to collinear laser spectroscopy • suitable for light elements(low QS values)

  19. Collinear laser and b-NMR spectroscopy • previous experiments at COLLAPS: • from the position of hyperfine transitions: spin assignment and sign of gI for the g.s. of 31Mg HFS 31Mg1+ basymmetry nRF (MHz) • from b-NMR: precise measurement of |gI| • strongly deformed intruder Ip = 1/2+ g.s. of 31Mg, G. Neyens et al, PRL 94, 022501 (2005) • from QS measurements via b-NMR: QS(11Li) > QS(9Li)  p-n interaction + halo n orbitals, D. Borremans, Ph.D. Thesis, 2004, KU Leuven, R. Neugart et al.

  20. b-NMR spectroscopy at DESIR • with I ≥ 5.103 pps, T½ from 1 ms to 10 s, beam purity > 50 %: • in combination with collinear laser spectroscopy whenever the spin and the configuration of the state is not known • in case QS is to small to be measured by collinear laser spectroscopy • N~50: • g factor of neutron-rich Ga and Cu isotopes to determine where the inversion of the pp3/2 and pf5/2 orbitals occurs • persistence of the N=50 shell gap from the g.s. configuration of N=49 (ng9/2) and N=51 (nd5/2) even Z nuclei (81,83Ge, 79,81Zn, 77Ni) • N~82: • g.s. configuration from gI measurements

  21. Double laser and RF spectroscopy in traps • RF scan of hyperfine transitions between Zeeman levels • No Doppler effect  accurate measurements • In a Penning trap (high magnetic field) • precise determination of the hyperfine constant A • high precision on gI (DgI/gI ~ 10-4) • hyperfine anomaly (nuclear magnetization extension) constraining the computation of the nuclear wave function • looking at different isotopes: neutron radius variations + PNC • In a Paul trap (low magnetic field) • precise determination of the hyperfine constants A, B as well as C (magnetic octupole moment) and D (electric exadecapole moment) = high-order deformation parameters

  22. Double laser and RF spectroscopy in traps • Previous results: O. Becker et al., Phys. Rev. A48, 3546 (1993) • at DESIR (I>100 pps, T½>100 ms) • hyperfine anomaly: Au, Eu, Cs • high-order deformation in the actinide region: Rn, Fr, Ra, Am

  23. TheLUMIEREcollaboration F. Le Blanc, G. Neyens (b-NMR), P. Campbell, K. Flanagan , S. Franchoo, C. Geppert, M. Kowalska, I. Moore, R. Sifi, C. Theisen, J.-C. Thomas,… and others are welcome !!!

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