D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Nuclear moments and structure of isomers in regions far from stability Dimiter L. Balabanski Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, A.D.

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, basic definitions experiments with fast beams orientation in fragmentation reactions how to approach ground state moments of exotic nuclei how to approach isomeric states how to approach short-lived states what can we learn from such measurements outlook experiments with post-accelerated ISOL beams Nuclear moments and structure of isomers in regions far from stability Dimiter L. Balabanski Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, more pages 193 Pb key issue: week exotic excitations e.g. magnetic rotation

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, key issue: week exotic excitations e.g. chiral rotation 128 Cs

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Q,  Z = 28 N = 40 key issue: shell structure away from stability

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, A schematic view of the basic methods of producing radioactive nuclear beams. At the top we see the ISOL method with and without a post-accelerator. Below we see the In-flight method and the proposed hybrid in which fragments are caught in a gas cell and then re-accelerated. In-flight Accelerator Thin production target Fragment separator In-flight post-accelerator Gas stopper Separator Accelerator Experiments ISOL Accelerator Thick production target ISOL ISOL trap Beam manipulation Post-accelerator Beam manipulation Separator Experiments ISOL post-accelerator The European perspective: present day ISOL: ISOLDE in-flight: GSI, GANIL post-accelerated ISOL: REX-ISOLDE near future in-flight: FAIR post-accelerated ISOL: Spiral2, HIE-ISOLDE far future: EURISOL In-Flight

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Nuclear moment measurements magnetic moment (  ) quadrupole moment (Q) single-particle configuration (configuration mixing) collective properties (deformation, effective charges) Spin-oriented beams

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Spin-aligned and spin-polarized beams some definitions m -2 – m -2 – spin-alignment spin-polarization

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,  = g l.l + g s.s  =  (j=l + 1/2) =  (j=l -1/2) = some more definitions Magnetic dipole moment in atomic nuclei  (I) = <I, m=I | | I,m=I> orbital momentum of the protons intrinsic spin of the nucleons Schmidt lines

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,   odd proton odd neutron j = l + 1/2 j = l – 1/2 j j = l + 1/2 j Schmidt lines

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, yet more definitions Electric quadrupole moment in atomic nuclei Q = =. Q(j) =

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, experimental approach Basic principles for moment measurements (ground states) magnetic dipole moments: experiments in external magnetic fields electric quadrupole moments: interaction with external electric fields, e.g. with a lattice field after implantation signal for  -decaying ground states: GT  -decay asymmetry (  -NMR,  -NQR) see talk of A.Yoshimi requirement: polarization of the spin ensemble

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, B J Fragment beam  L = -g  N B/h Measure Larmor precesion and decay I(  t) Time Differential Perturbed Angular Distribution  t=0 time Field UP Field DOWN 2L2L 2A 2 B 2 the relative phases depend on the g-factor time detectors at ±45° and ±135° isomeric sates (ns −  s) requirement: alignment of of the spin ensemble signal : time dependence of the intensity of the decay  rays TDPAD

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, ALIGNMENT(%) +6.2(7)% 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 ! 61Fe YIELD 61Fe -15.9(8)% 61Fe

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, /2- 5/2+ 9/ T 1/2 = 13.3  s 67 Ni ss autocorrelation R(t)  L (Mrad/s) Amplitude Fourrier spectrum G. Georgiev et al. J.Phys. G 28, 2993 (2002)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, MeV/u; 9 Be target A1900 – 90% beam purity

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, I. Matea et al. PRL 93 (2004)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, keV M1 transition 654 keV M2 transition Q( 61m Fe; g 9/2 ) = 41(6) mb GANIL did a press release on this result ! Time-differential perturbed angular distributions test case 61 Fe exp. July 2005 principle investigators: Micha Hass (Rehovot) and Jean-Michel Daugas (Bruyeres-la-Chatel) Analysis: Nele Vermuelen, Leuven and Chamoli, Rehovot (PR C 75, )  2 = or +0.24

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, (d,p) reaction, Tandem-ALTO, Orsay  Q s ( 61 Fe; 9/2 + )  = 41(6);  2 > 0 Q s ( 65 Cu; 3/2 − ) = −19.5(4);  2 < 0 Q add = Q   Q = 21.5(60) efm 2

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, classical view quantum-mechanical view Population I = 2 E m =2 m =1 m =0 m =-1 m =-2 I=2 ensemble Necessary to induce polarization of the beam prior the measurement ISOL beams

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Electromagnetic moments in transfer reactions 98 Mo 99 Mo 100 Tc 100 Mo 101 Mo 102 Tc 63 Cu 64 Cu 65 Zn 65 Cu 66 Cu 67 Zn P P populate low-spin (single-particle) states go a step further in the Nuclear Terra Exotica G. Georgiev (Orsay, France) and D.L. Balabanski (INRNE – BAS, Sofia)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, What do we want to do next ? targets: 62,64 Ni beams: 63,65 Cu test case: g = (5) Cu-beam D 2 target electromagnet 3.5 MeV/u S2 detector of TIARA T 1/2 = 20ns use particle –  coincidences instead of beam pulsing

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, inverse kinematics 63 Cu 220 MeV (3.5 MeV/u) CD 2 target (2 mg/cm 2 ) Ni ferromagnetic backing (15 µm) permanent magnet for holding field Particle identification: Si strip detector (8 annular strips) as  E CsI 16 sectors – as E detector angular coverage 25° - 60°

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, The CD detector of TIARA The CsI detector Particle detection with TIARA (in collaboration with Surrey, Birmingham)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Particle-  vs. beam pulsing Try to avoid the particle-  correlations if not absolutely necessary

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, short-lived (ps) states Transient field technique requirement: alignment of of the spin ensemble signal: rotation of the angular distribution of the  rays interaction: very high transient magnetic field (tens of Tesla)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Honma et al., PR C 80, (2009) in the calculation f 7/2 is frozen! Question: Is there deviation from the hydrodynamic limit?

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Spin-alignment in projectile fission and g-factors around 132 Sn (Gerda Neyens and Gary Simpson) g-RISING EXPERIMENTS performed Oct – Dec Spin-alignment and g-factors of isomers in 127,128 Sn from fragmentation of a 136 Xe beam. (Dimiter Balabanski and Michael Hass) Sn 238 U-fission at 750 MeV/u 136 Xe-fagmentation at 700 MeV/u

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, THE EXPERIMENTAL SET-UP AT GSI: g-RISING Spin-aligned secondary 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

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, The 136 Xe fragmentation experiment Z A/q 127 Sn analysis:L.Atanasova, Sofia

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Momentum selection Position at Sc21 Isomeric ratio (arbitrary units) 25%

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Sn 127 Sn J. Pinston et al., PRC 61, (2000) 4.5(3)  s  -ray spectra gated on 127 Sn

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech,  s isomers in the Sn region N=82 1g 7/2 1h 11/2 3s 1/2 2d 3/2 2d 5/2 N=50 J. Pinston et al, PRC (2000), J. Pinston et al, JPG30 (2004) R57, NNDC data base and this work    d 3/2 -1 h 11/2 -1 Odd Sn Even Sn    d 3/2 -1 h 11/2 -2   h 11/2 -    d 3/2 -1 h 11/2 -1    d 3/2 -1 h 11/2 -2 h 11/2 x 5 - core h 11/2 x 7 - core    h 11/2 -  h 11/2  s 1/2 -1 d 3/2 -2 Brown et al, PRC71 (2005) Newly identified isomers R. Lozeva, PR C 77, (2008)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, B = 0.12 Tg = Choice of the magnetic field g = 0.16 R(t, ±B) = 3A4+A sin(2  L t) I 1 = (A+L)  + (D+G)  I 2 = (A+L)  + (D+G) 

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, keV 715 keV FFT TDPAD 715 keV L. Atanasova, Europhys. Letters in preparation g =  0.17(2)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, G.Ilie et al, Phys. Lett. (submitted) Analysis S.K. Chamoli; L. Atanasova et al, Europhys. Lett. (in preparation) g(7  ; 126 Sn) =  0.097(3) g(10 + ; 128 Sn) =  0.20(4)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, 7 /2 + 7  : 114,116 Sn and 130 Sn 10 + : 116,118 Sn 19/2 + : none Sn neutron-rich isomers 11/2 

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Structure of the 19/2 + isomer in 127 Sn the spin-parity assignment of the 19/2 + isomer is based on energy systematics J. Pinston et al., PRC 61, (2000) ν suggested configuration: ( ν h 11/2  1  5  ) 19/2 +; g exp (h 11/2 ) =  0.24 the 5  isomers in even-even Sn isotopes take experimental values: g exp (5  )   0.06 ν and are understood as an admixture of ( ν h 11/2  1 d 3/2  1 ) 5 - with g emp =  0.26 ν ( ν h 11/2  1 s 1/2  1 ) 5 - with g emp =  0.09 for the structure of the 19/2 + isomer an admixture with the νg 7/2  1 h 11/2  2 configuration is suggested in order to explain the l -forbidden M2 isomer-decay transition. g emp (νs 1/2  1 h 11/2  2 ) =  0.15 g emp (νg 7/2  1 h 11/2  2 ) =  0.23 the fragmentation g-RISING experiment yields g exp =  0.17(2) LSSM calculations yield g SM =  0.11 (calculation M.Hjorth-Jensen)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, K.U. Leuven, Belgium: M. De Rydt, R. Lozeva, S. Mallion, G. Neyens, K. Turzó, N. Vermeulen 2. INRNE, Sofia, Bulgaria: D.L. Balabanski 3. University of Sofia, Bulgaria: L. Atanasova, P. Detistov 4. ILL Grenoble, France: G. Simpson 5. CEA, Bruyères le Chatel, France:J.M. Daugas, O. Perru 6. CSNSM – Orsay, France: G. Georgiev 7. ISKP Bonn, Germany: H. Hübel, S Chmel 8. GSI-Darmstadt, Germany: F. Becker, P. Bednarczyk, L. Caceres, P. Doornenbal, J. Gerl, H. Grawe, M. Górska, I. Kojuharov, N. Kurz, W. Prokopowicz, T. Saito, H. Schaffner, E. Werner-Malento, H.J. Wollersheim 9. IKP Koeln, Germany: J. Jolie, G. Illie, A. Blazhev 10. IKHP Rossendorf, Germany: R. Schwengner, G. Russev 11. ATOMKI, Debrecen, Hungary: A. Krasznahorkay 12. The Weizmann Institute, Israel: S. Chamoli, M. Hass, S. Lakshmi 13. University of Camerino, Italy: G. Lo Bianco, A. Saltarelli 14. LNL Legnaro, Italy: J.J. Valente-Dubon 15. University of Milano, Italy: G. Benzoni, N. Blasi, A. Bracco, F. Camera, F. Crespi, D. Montanari, O. Wieland 16. U. Padova and INFN Padova, Italy: D. Bazzacco, E. Farnea 17. INFN-Perugia, Italy: K. Gladnishki 18. IFJ-PAN Krakow, Poland: J. Grębosz, M. Kmiecik, A. Maj, K. Mazurek, W. Męczyński, S. Myalsky, J. Styczeń, M. Ziębliński 19. Jaggielonian University, Krakow, Poland: R. Kulessa 20. Warsaw University, Poland: M. Pfűtzner 21. NIPNE, Bucharest, Romania: M. Ionescu-Bujor, A. Iordachescu 22. Universidad Autonoma de Madrid, Spain: A. Jungclaus 23. Univerity of Lund, Sweden: C. Fahlander, R. Hoishen, D. Rudolf 24. University of Surrey, UK: Zs. Podolyàk, P. Regan, J. Walker, S. Pietri, C. Brandau. The g-RISING collaboration: 71 researchers from 24 institutions

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Quadrupole moment measurement of the 8 + isomer in 96 Pd using the RISING stopped-beam set up Spokespersons : Michael Hass (WI) and Dimiter Balabanski (Sofia/Camerino) GSI contact: Juergen Gerl INRNE, Bulgarian Academy of Sciences, Bulgaria: D.L. Balabanski Weizmann Institute, Israel: G. Goldring, M. Hass, V. Kumar University of Sofia, Bulgaria: L. Atanasova, P. Detistov, K. Gladnishki, S. Lalkovski, G.I. Rainovski CSNSM, Orsay, France: G. Georgiev K.U. Leuven, Belgium: M. De Rydt, R. Lozeva, G. Neyens, N. Vermeulen University of Camerino, Italy: G. Lo Bianco, A. Saltarelli, S. Nardelli University of Milano, Italy: G. Benzoni, N. Blasi, A. Bracco, F. Camera, F. Crespi, S. Leoni, B. Million, O. Wieland LNL, Padova, Italy: G. De Angelis, A. Gadea, R. Orlandi, E. Sahin University of Surrey, UK: A. Garnsworthy, S. Pietri, Zs. Podolyàk, P. Regan, S. Steer University of Brighton, UK: A. M. Bruce University of York, UK: B.S. Nara Singh Universidad Autonoma de Madrid, Spain: L. Caceres, A. Jungclaus, V. Modamio, J. Walker University of Istanbul, Turkey: M.N. Erduran IKP Koeln, Germany: A. Blazhev, G. Ilie, J. Jolie University of Lund, Sweden: D. Rudolph, C. Fahlander, R. Hoisen IFJ PAN Krakow, Poland: A. Maj, M. Kmiecik, J. Grebosz, P. Bednarczyk, K. Mazurek, S. Myalski GSI-Darmstadt, Germany: F. Becker, C. Brandau, P. Doornenbal, J. Gerl, M. Gorska, H. Grawe, I. Kojuharov, N. Kurz, W. Prokopowicz, H. Schaffner, S. Tachenov, H.J. Wollersheim An experiment that we could not make!

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, in this experiment we aim to measure the quadrupole moment of the 8 + isomer in 96 Pd which has four holes in the Z = 50 shell Sn MOTIVATION: Q(8 + ) is a probe for the break down of the  g 9/2 n seniority scheme

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Seniority mixing has been experimentally established from a measurement of B(E2) transition strengths from the 4 + states in 96 Pd and 94 Ru. Large scale shell model calculations fully account for the experimental data in 96 Pd and 94 Ru and prove that the mixing is due to ph excitations across the N=50 closed shell. H. Grawe et al, EPJ A (2006)  20% spread of predictions

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, The 8 + isomer in 96 Pd was produced in the fragmentation of the 107 Ag beam at 750 MeV/u during S244 RISING experiment; we suggest to perform the moment measurement under the same conditions PRODUCTION OF THE 96 Pd ISOMER

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Polarized beams at HIE-ISOLDE – from dreams to reality. G. Georgiev 1, M. Hass 2, A. Herlert 3, D.L. Balabanski 4, L. Hemmingsen 5, K. Johnston 3, M. Lindroos 3, K. Riisager 6, J. Van de Walle 3, D. Voulot 3, F. Wenander 3, W.-D. Zeitz 7 1. CSNSM, Orsay, France; 2. The Weizmann Institute, Rehovot, Israel; 3. ISOLDE, CERN, Geneva, Switzerland; 4. INRNE, BAS, Sofia, Bulgaria; 5. IGM, LIFE, University of Copenhagen, Denmark; 6. Department of Physics and Astronomy, University of Aarhus, Denmark; 7. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany Polarized beams – WHY? Precise test of the nuclear models for exotic nuclei: transfer reactions (analyzing power) Coulomb excitation – spin/parity; multiplicity assignments etc. nuclear moments – proton/neutron character, angular momentum j

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Can one do it and how? M. Hass et al., NPA 414, 316 (84) Tilted Foils - the principles: atomic polarization  nuclear polarization higher nuclear spins  higher polarization (>10% achieved so far) strong velocity dependence (poorly studied up to now) Can one post-accelerate the ions after polarizing them? done for stable beams - noble-gas like charge states + LINAC  J. Bendahan et al., ZPA 331, 343 (88)

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, unique opportunity What do we need to achieve it? 3 MeV/u and 0.3 MeV/u  -NMR setup from HMI Berlin transferred to ISOLDE gain of complete control on the TF polarization nuclear structure (moments, reactions …), nuclear methods in the solid-state physics, biophysics etc. …

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, Conclusions fragmentation reaction at intermediate energies are proved to be a reliable tool for nuclear moment measurements; fragmentation reactions at relativistic energies are rather difficult to handle, BUT need to be used for medium and heavy nuclei; transfer reactions (and incomplete fusion) are an option to approach neutron-rich nuclei; polarization of post-accelerated beams is the next c hallenge to address

D.L. BalabanskiPhysics of Nuclei at Extremes, T.I.Tech, This work wouldn’t have been possible without the fruitful collaborations with my friends Georgi Georgiev, Gerda Neyens, Micha Hass, and Jean-Michel Daugas