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Nuclear moments of isomeric states studied in transfer reactions in inverse kinematics

Nuclear moments of isomeric states studied in transfer reactions in inverse kinematics. moments of exotic isomers: where are we now and what we want to do in near future. Nuclear moment measurements. Spin-oriented beams. magnetic moment (  ) quadrupole moment (Q).

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Nuclear moments of isomeric states studied in transfer reactions in inverse kinematics

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  1. Nuclear moments of isomeric states studied in transfer reactions in inverse kinematics • moments of exotic isomers: where are we now and what we want to do in near future EURISOL workshop, Florence, 16.01.2008

  2. Nuclear moment measurements Spin-oriented beams magnetic moment () quadrupole moment (Q) single-particle configuration (configuration mixing) collective properties (deformation, effective charges) EURISOL workshop, Florence, 16.01.2008

  3. Spin orientation alignmentprolate oblate isotropic polarization  b - decay  g – ray detection EURISOL workshop, Florence, 16.01.2008

  4. Magnetic moment Quadrupole moment  = <I, m=I | z |I,m=I> Q = = g I N Q(j) = = . what we want to measure EURISOL workshop, Florence, 16.01.2008

  5. how are done these measurements EURISOL workshop, Florence, 16.01.2008

  6. METHODOLOGY Time Differential Perturbed Angular Distribution Measure Larmor precesion and decay I(t) B  J Fragment beam L = -gNB/h Field UP Field DOWN detectors at ±45° and ±135° time 2A2B2 the relative phases depend on the g-factor 2L t=0 time EURISOL workshop, Florence, 16.01.2008

  7. Fusion-evaporation reaction fragmentation reaction • the present tool : • 20 % spin-polarization (low yield) • 10 ÷ 30 % spin-alignment (high yield) basic tool for obtaining of spin-aligned nuclei in the past two-three decades where are we now EURISOL workshop, Florence, 16.01.2008

  8. YIELD 61Fe 61Fe 61Fe 61Fe +6.2(7)% ALIGNMENT(%) -15.9(8)% GENERAL ASPECTS of g-factor measurements with fast beams 4. FEASIBILITY: SPIN-ALIGNMENT ! PROJECTILE FRAGMENTATION + selection in longitudinal momentum (slits in FRS or via ion-correlation) CONDITION: STRIPPED FRAGMENTS ! EURISOL workshop, Florence, 16.01.2008

  9. M. Pfützner et al., Phys. Rev. C65 (2002) 064604; K. Gladnishki et al., Phys. Rev. C69 (2004) 024617 Higher spins for greater DA. EURISOL workshop, Florence, 16.01.2008

  10. Experiments at GANIL at intermediate energies (credits to Micha Hass, Jean-Michel Daugas, Georgi Georgiev, Gerda Neyens, Iolanda Matea and Nele Vermuelen) gexp. (61mFe) = - 0.229(2) I. Matea et al. PRL 93 (2004) 142503 G. Georgiev, JP G 28 (2002) 2993 EURISOL workshop, Florence, 16.01.2008

  11. Quadrupole moments: 61Fe principle investigators: Micha Hass (Rehovot) and Jean-Michel Daugas (Bruyeres-la-Chatel) test case 61Fe exp. July 2005 Q(61mFe; g9/2) = 422(60) mb 654 keV M2 transition 201 keV M1 transition EURISOL workshop, Florence, 16.01.2008

  12. Spin-alignedsecondary beam selected (S2 slits + position selection in SC21) SC41 gives t=0 signal for -decay time measurement Implantation: plexiglass degrader + 2 mm Cu (annealed) SC42 and SC43 validates the event THE EXPERIMENTAL SET-UP AT GSI: g-RISING EURISOL workshop, Florence, 16.01.2008

  13. The 136Xe fragmentation experiment Z 127Sn analysis:L.Atanasova, Sofia A/q EURISOL workshop, Florence, 16.01.2008

  14. M2 715 keV E1 1095 keV E2 ?? EURISOL workshop, Florence, 16.01.2008

  15. 715 keV 715 keV TDPAD 1095 keV FFT EURISOL workshop, Florence, 16.01.2008

  16. I=2 ensemble classical view quantum-mechanical view m =2 m =-2 m =1 m =-1 m =0 I = 2 Population E Necessary to induce polarization of the beam prior the measurement ISOL beams EURISOL workshop, Florence, 16.01.2008

  17. Part II: The future: Transfer reactions with RIBs The 63m,65mNi experiment (I = 9/2+) (d,p) reactions Tandem at IPN-Orsay • pulsed 6 MeV 1 nAD beam • enriched 64Ni/62Ni (ferromagnetic) targets • known g(63mNi) = - 0.269(3) • Muller et al. PR B40, 7633 (1989) • HF field of Ni(Ni) = 6.90(5) T • Riedi et al. PR B15, 5197 (1977) EURISOL workshop, Florence, 16.01.2008

  18. Larmor frequency Part II: The future: Transfer reactions with RIBs Experimental results 63mNi 65mNi G. Georgiev et al, J.Phys.(London) G31, S1439 (2005) Ni exp. 2004 gexp. = -0.296 (3) HF field Ni(Ni) = 6.90(2) T ~ 15% alignment in transfer reactions at the Coulomb barrier (3 MeV/u) EURISOL workshop, Florence, 16.01.2008

  19. inverse kinematics 63Cu beam @ 220 MeV (3.5 MeV/u) CD2target (2 mg/cm2) Ni ferromagnetic backing (15 µm) permanent magnet for holding field Particle identification: Si strip detector (8 annular strips) as ECsI 16 sectors – as E detector angular coverage 25° - 60° EURISOL workshop, Florence, 16.01.2008

  20. EURISOL workshop, Florence, 16.01.2008

  21. Particle detection with TIARA (in collaboration with Surrey, Birmingham) The CD detector of TIARA The CsI detector EURISOL workshop, Florence, 16.01.2008

  22. EURISOL workshop, Florence, 16.01.2008

  23. EURISOL workshop, Florence, 16.01.2008

  24. orientation in transfer • Single-nucleon transfer (d,p) • 65Ni • B2 = 0.159(5) • 66Cu • B2 = 0.452(13) • 64Cu • “standard” B2 = 0.09 (?) • with p-g coincidences B2 > 0.27 • Multi-nucleon transfer states with higher spin become accessible (!) EURISOL workshop, Florence, 16.01.2008

  25. Towards the use of ISOL beams • With radioactive beams the reaction products should be stopped in the target (isomeric state) while the beam should be let go through – very fine control of the target thickness needed • Single-nucleon transfer: • very clean experimental conditions (very few reaction channels opened) • reasonable orientation from the reaction • mostly single-particle states accessible • very difficult separation of the beam/reaction products • Multi-nucleon transfer: • many more reaction channels opened • orientation higher than in single-nucleon transfer • multi quasi-particle states accessible as well • the separation of the beam/reaction products should be easier EURISOL workshop, Florence, 16.01.2008

  26. 64Cu – target problems A CD2 target of ~2 mg/cm2dose not stand ~0.3 enA (17+) 63Cu beam (~1E8 pps) for more than 20 hours (~7E12 p) The effect is DOSE and not HEAT related! EURISOL workshop, Florence, 16.01.2008

  27. Targets: Hydrogen (Deuterium) storage T. Yildirim et al. PR B72, 153403 (2005) EURISOL workshop, Florence, 16.01.2008

  28. collaboration (or in other words) who is doing the job • GANIL experiments • Jean-Michel Daugas, Micha Hass, … • GSI experiments • Gerda Neyens, Gary Simpson, Adam Maj, Micha Hass, DLB • Transfer reactions • Georgi Georgiev and DLB • + few (but good!) students and post-docs who really do the job! EURISOL workshop, Florence, 16.01.2008

  29. N=82 1h11/2 3s1/2 2d3/2 2d5/2 1g7/2 Even Sn 5- nd3/2-1h11/2 -1 7-nd3/2-1h11/2 -1 10+h11/2 -2 N=50 Odd Sn 19/2+ nd3/2-1h11/2 -2 23/2+ nd3/2-1h11/2 -2 27/2-h11/2 -3 nh11/2 x 5-core nh11/2 x 7-core h11/2n, n=2,3 ms isomers in the Sn region Newly identified isomers ns1/2-1 Brown et al, PRC71 (2005) 044317 nd3/2-2 J. Pinston et al, PRC61 024312 (2000) , J. Pinston et al, JPG30 (2004) R57, NNDC data base and this work EURISOL workshop, Florence, 16.01.2008

  30. Structure of the 19/2+ isomer in 127Sn • the spin-parity assignment of the 19/2+ isomer is based on energy systematics • J. Pinston et al., PRC 61, 024312 (2000) • suggested configuration:(νh11/2 1 5)19/2+; gexp(h11/2) = 0.24 • the 5 isomers in even-even Sn isotopes take experimental values:gexp(5)  0.06 • and are understood as an admixture of (νh11/2 1d3/2 1)5- withgemp = 0.26 • (νh11/2 1s1/2 1)5- withgemp = 0.09 • for the structure of the 19/2+ isomer an admixture with the νg7/2 1h11/2 2 configuration is • suggested in order to explain the l -forbidden M2 isomer-decay transition. • gemp(νs1/2 1 h11/2 2) = 0.15 • gemp(νg7/2 1 h11/2 2) = 0.23 • the fragmentation g-RISING experiment yields gexp  0.16 • LSSM calculations yieldgSM = 0.21 (calculation M.Hjorth-Jensen) EURISOL workshop, Florence, 16.01.2008

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