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K.U. Leuven The Belgian Research Initiative on eXotic nuclei (BriX) Piet Van Duppen Instituut voor Kern- en Stralingsfysica - K.U.Leuven Belgium Introduction.

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Presentation on theme: "K.U. Leuven The Belgian Research Initiative on eXotic nuclei (BriX) Piet Van Duppen Instituut voor Kern- en Stralingsfysica - K.U.Leuven Belgium Introduction."— Presentation transcript:

1 K.U. Leuven The Belgian Research Initiative on eXotic nuclei (BriX) Piet Van Duppen Instituut voor Kern- en Stralingsfysica - K.U.Leuven Belgium Introduction Nuclear physics research in Belgium Research funding The “Interuniversity Attraction Poles Program”: historical note The BriX network “Advanced Research on Exotic Nuclei for Nuclear Physics and Nuclear Astrophysics” Research highlights (experimental part, theory discussed by J.-M. Sparenberg) Conclusion and Outlook

2 K.U. Leuven Nuclear physics research in Belgium Federal laboratory

3 K.U. Leuven Fundamental nuclear physics research funding: Federal: “Interuniversity Attraction Poles Program” Regional: Universities: EU: Nuclear physics research in Belgium: funding

4 K.U. Leuven Interuniversity Attraction Poles Program PeriodPartnersResearch Activities U.C.L. – U.L.B. – K.U.Leuven U.C.L. – U.L.B. – K.U.Leuven U.C.L. – U.L.B. – K.U.Leuven U.C.L. – U.L.B. – U.Gent - K.U.Leuven U.L.B. – U.Gent – SCKCEN - K.U.Leuven Nuclear Structure Nuclear Astrophysics -Radioactive beam production - 6 He, 10,11 C, 15 O, 18 F, 18,19 Ne - Resonant laser ionization of exotic nuclei - New instrumentation - Laser ion source - LEDA array (segmented silicon detector) - MINIBALL (segmented germanium detector array) - Penning trap for weak interaction studies - Nuclear astrophysics: exp. and theory (e.g. 13 N(p,  )) - Nuclear structure and reactions: experiment - ground-state properties (moments, charge radii) - decay studies - Coulomb excitation - fusion, fission and transfer reactions - Nuclear structure and reactions: theory - Cluster models, few-body approaches, shell-model, mean-field, symmetry based approaches - Fundamental interaction studies

5 K.U. Leuven The Belgian Research Initiative on eXotic nuclei (BriX) ( ) Belgian partners: P. Descouvemont, D. Baye, P.-H. Heenen, J.-M. Sparenberg K. Heyde, C. Wagemans H. Aït Abderrahim, P. Baeten, P. Schuurmans M. Huyse, G. Neyens, N. Severijns, R. Raabe, P. Van Duppen International partners: GSI (Germany) GANIL (France) CSNSM (France) U.Köln (Germany)

6 K.U. Leuven ISOLDE - CERN GSI-Darmstadt GANIL-Caen KVI-Groningen CRC-Louvain-la-Neuve The Belgian Research Initiative on eXotic nuclei (BriX) ( ) ILL- Grenoble Facilities Species: from neutron beams to radioactive ion beams Energy: from ~ rest up to 50 MeV/u Half-life: from ms to hours

7 K.U. Leuven Z=28 Z=50 N=40 Z=82 20 N=50 N=82 N Z Structure of light exotic nuclei Towards 78 Ni: shell structure along Z=28 and N=50 Shape coexistence along Z=82 Nuclear structure along the N=Z line Fundamental interaction studies n-induced and beta-delayed fission The Belgian Research Initiative on eXotic nuclei (BriX) ( ) Feasibility study for “Island of inversion around 32 Mg” Physics

8 K.U. Leuven Laser ion source LISOL - Leuven Isotope Separator On-Line Louvain-la-Neuve Radioactive Beam Facility LISOL gas cell Laser beams Target Cyclotron beam Exit hole Sextupole Ion Guide Ar/He from gas purifier Filament CYCLONE110 cyclotron p,d,  and heavy ions Radioactive Ion Beams Laser System Detection Laser ion source Thermalisation in a buffer gas cell (500 mbar Ar) Resonant laser ionization: Z-selection (isomer) Mass separation: A/Q selection [M. Facina,- NIMB 226 (2004) 401] [Y. Kudryavtsev,- NIMB 204 (2003) 336]

9 K.U. Leuven Wide spectrum of pure radioactive ion beams Energy: from ~ rest up to 3 MeV/u Post accelerated beams: 8,9,11 Li, Be, 10 C, 17 F, Na, Mg, 61,62 Mn, 61 Fe, 68 Ni, 67-71,73 Cu, 74,76,78,80 Zn, 70 Se, 88,92 Kr, 96 Sr, 108 In, 106,108,110 Sn, 122,124,126 Cd, 138,140,142,144 Xe, 140,142,148 Ba, 148 Pm, 153 Sm, 156 Eu, 182,184,186,188 Hg, 202,204 Rn F. Ames et al., Nucl. Instrum. Methods A 538, 17 (2005) F. Wenander et al., Nucl. Phys. A701, 528 (2002) O. Kester et al., Nucl. Instrum. Methods B 204, 20 (2003)

10 K.U. Leuven München, Köln, Heidelberg, Darmstadt, Leuven, York, Liverpool, Daresbury, Strasbourg,... The MINIBALL detector array J. Eberth et al., Prog. Part. Nucl. Phys. 46, 389 (2001) Miniball 120 Sn REX- ISOLDE PPAC Beam monitor CD – detector Double sided Si strip detector (2.3 mg/cm 2 ) Coulomb excitation Si barrel detector Miniball Transfer reactions

11 K.U. Leuven 9 He unbound 10 He unbound 9 Li 179 ms 10 Li unbound 12 Be 23.6 ms 9 B unbound 10 B 11 B 12 B ms 12 Li unbound 9 C 125 ms 10 C 19.3 s 11 C 20.4 m 11 Li 8.5 ms 9 Be 10 Be y 11 Be 13.8 s 12 C 12 N 11 ms 11 N unbound 12 O unbound N Z Structure of light exotic nuclei: properties of key states Beta-decay studies by implantation in a highly pixelated Si detector and decay correlations Calorimetric technique: full energy measured low threshold high efficiency precise normalisation Measured: 6 He (LLN), 11 Li (TRIUMF) (2n-halos) 12 N, 12 B (KVI) (3-alpha states in 12 C) 8 B (KVI) (spectrum of solar neutrinos) 11 Li: R. Raabe,- PRL 101 (2008) N, 12 B: S. Hyldegaarda,- PLB submitted 6 He: R. Raabe,- PRC submitted 8 B: analysis in progress

12 K.U. Leuven 11 Li: deuteron emission - decay of the halo Theory: U.L.B. Raabe et al., PRL 101 (2008) Structure of light exotic nuclei: properties of key states Resonance above (V a ) or below threshold (V b ) Coulomb contribution (V C )

13 K.U. Leuven Present status of the “Island of inversion” as deduced from static and dynamic moments measurements “Island of inversion” around 32 Mg

14 K.U. Leuven Production of Al isotopes at GANIL   -NMR on polarized fragment beams g=1.532(2) g=1.635(2) P. Himpe et al., Phys. Lett. B 643 (2006) 257–262 Conclusion: small (<25-30 %) intruder admixture in the 33 Al ground state. “Island of inversion” around 32 Mg: moment measurements

15 K.U. Leuven Mark Huyse “Island of inversion” around 32 Mg: two-neutron transfer reactions Radioactive beam onto a radioactive target 3 H( 30 Mg, 32 Mg) 1 H Si barrel detector MINIBALL germanium detector ISOLDE - IS470: Kathrin Wimmer

16 K.U. Leuven First Ionization Limit cm-1 CuI: ground state Cu + + e - 1 = nm 2 = nm cm -1 2 S 1/2 4 P 0 1/2 65 Cu 63 Cu 59 Cu 57 Cu: 6 ions/s Frequency [GHz] F=1 F=2 F=1 56 Ni 6.0 d 57 Cu 199 ms 54 Co 55 Ni 209 ms 55 Co 17 h 57 Ni 36 h 58 Ni Z=28 N=28 In-gas-cell laser spectroscopy of 57,59 Cu: a sample of spectra

17 K.U. Leuven In-gas-cell laser spectroscopy of 57,59 Cu: results [K. Minamisono,- PRL 96 (2006) ]

18 K.U. Leuven 5/2 - 3/2 - 5/2 - 3/2 - N=40 N=50 S. Franchoo et al., PRL81 (1998) 3100, PRC64 (2001) N. Smirnova et al., PRC69 (2004) A. Lisetskiy et al, PRC (2004) T. Otsuka et al., PRL 85 (2005) Experiment Theory 28 neutronsprotons g 9/2 f 7/2 f 5/2 40 p 3/2 p 1/2 “monopole interaction” g 9/2 Z=28 Monopole interaction towards 78 Ni: Cu (Z=29)

19 K.U. Leuven A =  the low B(E2; 5/2 -  3/2 - ) value from N=40 onwards indicates that the 5/2 - state is essentially of single-particle character Results: the 5/2 - states  at N=40 ( 69 Cu), the 5/2 - 1 states undergo a significant loss in collectivity, are of different character I. Stefanescu et al., PRL 100, (2008 ) I. Stefanescu et al., PRL 98, (2007)

20 K.U. Leuven A =  onset of collectivity related to the filling of the g9/2 neutron state.  the proposed 1/2 - shows an important increase in collectivity beyond N=40; Results: the 1/2 - states  the low B(E2; 5/2 -  3/2 - ) value from N=40 onwards indicates that the 5/2 - state is essentially of single-particle character  at N=40 ( 69 Cu), 5/2 - states undergoes a significant loss in collectivity, are of different character I. Stefanescu et al., PRL 100, (2008 ) I. Stefanescu et al., PRL 98, (2007)

21 K.U. Leuven 3/ / / / / / / / / / / / / / / / /2 + ~2500 9/ / / / / / / / / / / / / / / / / / / / /  f 5/2  p 3/2  2 + ( A-1 Ni)  f 7/2 :  (2p-1h) N=40 N=28 Energy systematics in the odd-mass Cu isotopes ? collective 1/2 - state  p 3/2  2 + ( A-1 Ni)

22 K.U. Leuven  Ground state spins, magnetic moments, quadrupole moments, charge radii from 61 Cu up to 75 Cu ! 73 Cu, I=3/2 75 Cu, I=5/2 No hyperfine anomaly  ratio of A-factors = constant if correct spin used in fit I=5/2 I=7/2 I=3/2 K.T. Flanagan et al., Collinear laser spectroscopy on Cu isotopes at ISOLDE

23 K.U. Leuven Shape co-existence in the lead region H. De Witte et al. PRL 98 (2007) Shape staggering Onset of deformation Mean square charge radii A.N. Andreyev et al., Nature 405, 430 (2000) 186 Pb 104 Potential energy surface Theory: U.L.B. – U.Gent

24 K.U. Leuven Strongly-coupled matrix elements Band mixing Sign, magnitude of deformation Shape co-existence in the lead region studied with Coulomb excitation Nick Bree, Andrew Petts et al Energy (keV) Coulomb 3 MeV/u 184 Hg (3 MeV/u) Cd

25 K.U. Leuven B f,i B f,e Spontaneous fission EC/  +  DF          a A.N. Andreyev et al. Rare charge-particle decay studies: ISOLDE and GSI Fission of 180 Hg observed in the beta decay of 180 Tl Unexpected asymmetric mass split ( 180 Hg (Z=80, N=100) = 2 x 90 Zr (Z=40, N=50) Cold fission, important for the end of the r-process Beta delayed fission

26 K.U. Leuven Study of (n,f) cross section measurements FWHM increases with increasing fissility parameter Z 2 /A of the compound nucleus: FWHM(SF) < FWHM(n,f): 0.3 MeV difference (excitation energy broadens) Improve data base for transmutation of minor actinides (e.g. 245 Cm) Ternary fission (e.g. 249 Cf): improve the understanding of the ternary fission process ( , t) important source of helium and tritium gas production in nuclear reactors C. Wagemans et al., Nucl. Sci. Engn. 160 (2008) 200 S. Vermote et al., Nucl. Phys. A806 (2008) 1 Complementary measurements at different facilities: thermal neutrons: high flux reactor at ILL and BR1 reactor at SCKCEN resonance neutrons at TOF facility at IRMM GELINA (GEel LINear Accelerator) IRMM Geel (Belgium)

27 K.U. Leuven Detect recoiling ions in singles for  angular correlation Select ion energies sequentially: retardation potential First recoil ion spectrum Preliminary Retardation potential (V) 124 Sn recoils proof of principle demonstrated system currently being upgraded and being prepared for measurement with 35 Ar in 11/2009 V.Yu. Kozlov et al., NIM B 266 (2008) 4515 S. Coeck et al., NIM A, 574 (2007) 370 S. Coeck et al., NIM A 572 (2007) 585 V.Yu. Kozlov et al., Hyp. Int. 172 (2006) 15 V.Yu. Kozlov et al., Int. J. Mass Sp. 251 (2006) 159 S. Coeck et al., NIM A 557 (2006) WITCH Penning trap at ISOLDE – Search for scalar weak currents

28 K.U. Leuven O. Naviliat-Cuncic & N. Severijns, Phys. Rev. Lett. 102 (2009) N. Severijns, I.S. Towner et al., Phys. Rev. C 78 (2008) N. Severijns et al., Rev. Mod. Phys. 78 (2006) 991 corrected ft-value for T = 1/2 mirror transitions : calculated from experiment nucleus dependent nucleus independent 29 P 19 Ne 21 Na 37 K 35 Ar New value of |V ud | : |V ud | = (17) 0 + →0 + neutron pion mirrors First consistent test of CVC from a set of nuclear transitions other than super-allowed pure Fermi Test of CVC and new value for V ud from T=1/2 mirror decays

29 K.U. Leuven S. Roccia et al., Phys. Rev. Lett., submitted A. Knecht et al., Phys. Rev. Lett., submitted K. Kirch et al., NIM A (2009) in print  - present goal: | d n | < 5 x e cm ( by ~ 2015 ; 4 experiments ) - several extensions of the Standaard Model predict values for d n in the range  e cm - present limit | d n | < 2.9 x e cm ( C.A. Baker et al., Phys. Rev. Lett. 97 (2006) ) - Standaard Model value for d n  e cm (from observed CP-violation in K- and B-meson decays) - observation of nEDM with larger value would point to NEW source of CP-violation; - could explain matter-antimatter asymmetry in the Universe Fundamental physics with neutrons at PSI: neutron electric dipole moment (nEDM)

30 K.U. Leuven Conclusion Belgian experimental nuclear physics activities under the BriX network: Radioactive beam production and use (from rest to 50 MeV/u) Broad spectrum of instrumentation, tools and techniques: Lasers, arrays of segmented Ge and Si detectors, Penning traps Moment and charge radii measurements, decay studies, Coulomb excitation, transfer reactions Physics: Nuclear-structure, nuclear reaction and fundamental interaction studies using neutrons and exotic nuclei

31 K.U. Leuven Outlook short and intermediate term Installation and use of the LISOL gas cell based laser ion source at the focal plane of the S3 project (intense heavy-ion beams, production of pure secondary beams, laser spectrocospy) Participation in DESIR (laser spectroscopy) ENERGY: Energy upgrade to 10 MeV/u and lower energy capacity INTENSITY: ISOLDE proton driver beam intensity upgrade strongly linked to PS Booster improvements including linac4 QUALITY: ISOLDE radioactive ion beam quality: broader spectrum and higher quality (purity, emittance, time structure) and isomeric beams European Separator On-Line Radioactive Nuclear Beam Facility

32 K.U. Leuven Nuclear Physics Research at the MYRRHA accelerator at SCKCEN 600 MeV,  A, D.C. proton beam (from the initial 2.5 mA for MYRRHA) Different target materials including uranium (e.g. UC: workhorse targets at present) Ruggedized target-ion source systems that deliver ~50 keV: ECR 1 + : gaseous elements (noble gases, C, N, O,..)) Surface ion source (hot cavity): alkaline and earth alkaline elements Laser ion sources Long beam times (e.g. 12 weeks) for experiments that: need very high statistics involve many time consuming systematic measurements hunt for very weak signals have an inherent low-detection efficiency Outlook long term ISOL target1 + ion source RF-cooler 1 + low-resolution separator 1 + high-resolution separator experiment MYRRHA accelerator In the field of fundamental interaction studies, nuclear physics, atomic physics, condensed matter research,… is complementary to other ISOL facilities and will be an integral part of the MYRRHA project (see talk H. Aït Abderrahim)

33 K.U. Leuven Thank you for your attention joined RNB-ENAM conference Organization of the joined RNB-ENAM conference in 2011 in Leuven Everybody is cordially invited. Outlook 2011

34 K.U. Leuven N=50 Z=28 N= sd-shell 1f 7/2 2p 1/2 1f 5/2 2p 3/2 sd-shell g 9/2 40  78 Ni p 1/2 g 9/2 f 5/2  Evolution towards 78 Ni along N=50  Onset of deformation Z>28 J. Van de Walle et al., PRL 99, (2007) J. Van de Walle et al., PRC 79, (2009) I. Stefanescu et al., PRL 100, (2008 ) I. Stefanescu et al., PRL 98, (2007) Coulex (up to 68 Ni, 73 Cu, 80 Zn) Decay studies Laser spectroscopy studies

35 K.U. Leuven Proton Number Neutron Number Ni Zn Ge N=50 isotones B(E2,2 + 1  ) [W.u.] E(2 + 1 ) [keV] B(E2,2 + 1  ) [W.u.] E(2 + 1 ) [keV] Ni,Zn,Ge isotopes this work

36 K.U. Leuven Proton Number Neutron Number Zn N=50 isotones B(E2,2 + 1  ) [W.u.] E(2 + 1 ) [keV] B(E2,2 + 1  ) [W.u.] E(2 + 1 ) [keV] Zn isotopes Shell Model (1) 56 Ni core : M. H. Jensen + monopole adjusted by Nowacki (e ,e  =(1.9e,0.9e) - (U.Gent - N. Smirnova et al, 2006)


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