1 / 43

Phenomena occurring in neutron deficient nuclei at N~50 M.G órska

Phenomena occurring in neutron deficient nuclei at N~50 M.G órska. location of the proton drip line single particle energy evolution spin-gap isomers: gamma and beta decaying valence and core excited states 100 Sn core excitation and shell gap measurement

newman
Download Presentation

Phenomena occurring in neutron deficient nuclei at N~50 M.G órska

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Phenomena occurring in neutron deficient nuclei at N~50M.Górska • location of the proton drip line • single particle energy evolution • spin-gap isomers: • gamma and beta decaying • valence and core excited states • 100Sn core excitation and shell gap measurement • enhanced collectivity in Sn isotopes • enhanced collectivity in Z>50 neutron deficient nuclei RISING experimental data and many others

  2. Experimental conditions and techniques • Fusion symmetric reaction EUROBALL, GASP + Ancillaries - in-beam - alpha decay MSEPat GSI - β decay - spin-gap isomers • Fragmentation - Coulex - Transfer - Isomers - β decay

  3. Experiments with Stopped Beams production selection spectroscopy identification stopping ~300MeV/u A,Z event-by-event ID Time correlation >50ns - min Rate < 1 ion/hour

  4. prompt g flash • isomeric ratio • gray sequence • spin-parity assignment • - • A,Z event-by-event ID • Time correlation ns - min • Rate < 1 ion/hour • Alignment → g, Q moment • + + -

  5. RISING Active Stopper Measurements Passive Stopper: g-ray from isomer cascades with T1/2 ~ 10 ns  1 ms. Active Stopper measurements: b-particles, internal conversionelectrons, alphas. T1/2 up to ~ minutes; associated with delayed g-rays. 5 cm x 5 cm DSSSD (16 strips x 16 strips = 256 pixels) x 3 = 758 total pixels or x2 layers or x3 layers.

  6. Experiments with fast beams production spectroscopy selection <1GeV/u identification reaction identification 100-700MeV/u 35m Bρ - ∆E - Bρ CATE SI-CsI

  7. Ge Cluster Ge Miniball RISING g-array for fast beams Scattering experiments : Coulomb excitation, One-, two-neutron knock-out Typically: 100MeV/u, εg=0.06, ∆Eg/Eg=0.02 Target chamber CATE beam

  8. Experimental conditions and techniques • Fusion symmetric reaction EUROBALL, GASP + Ancillaries - in-beam MSEPat GSI - β decay - spin-gap isomers • Fragmentation - Coulex -Transfer - Isomers - β decay

  9. Scenario: high temperature and density (x-ray bursts in neutron stars) Nuclei can be synthesized successively by binding more and more protons until proton dripline is reached. Continuation to heavier nuclei after β+-decay. β+ emitters with longer half lives are called waiting point nuclei rp-process rp process waiting points N = Z H. Schatz et al. PRL 86, 2001

  10. The closed SnSbTe cycle Where does the rp-process end? rp process H. Schatz et al. PRL 86, 2001 waiting points • Measurement • total life time of waiting point nuclei • exact position of proton dripline N = Z

  11. Te Sb Sn In Cd Ag Pd Rh Ru Probing the proton dripline T.Faestermann TU München analysis: K.Eppinger, C.Hinke 100Sn setting 100Sn

  12. what‘s new? 103Sb T1/2 < 50 ns ! 99Sn? T1/2 > 0.2 ms 97In 95Cd 93Ag

  13. 100Sn region 100Sn region Tensor interaction monopole νh11/2 – πg9/2, νg7/2 – πg9/2 T. Otsuka et al., PRL 95, 232502 (2005) EXP: h11/2<30% spectroscopic strength very old measurements h11/2›50% spectroscopic strength h11/2<30% spectroscopic strength New ! πν interaction tuned for the model space 88Sr,p(p1/2,g9/2) n(d5/2, g7/2, d3/2, s1/2, h11/2) gives the correct description of the evolution of SPEs M. Górska et al., Proc. ENPE99, AIP CP495 (2000) 217 M. Hjorth-Jensen et al., Phys. Rep. 261 (1995) 125 and priv. comm. M. Górska et al., Proc. ENPE99, AIP CP495 (2000) 217 M. Hjorth-Jensen et al., Phys. Rep. 261 (1995) 125 a

  14. 56Ni and 100Sn analogy 1ћw apart: (nlj) → (n+1,l+1,j+1) If the orbits are the same the physics cannot be (much) different ! The Jan Blomqvist correspondence principle

  15. Spin gap isomers below N = Z = 50 with RISING and GSI - ISOL • proton – neutron hole-hole interaction in pn g9/2-n • core excitation in large-scale SM in pn g9/2-1 (d5/2 ,g7/2)1

  16. 8+ 2428 6+ 2281 2083 4+ 1395 2+ 0+ 0 100Sn setting check : 98Cd 12+ 6635 M.G. et al., PRL 79 (1997) 2415 198 A. Blazhev et al., PRC 69, 064304 (2004) 688 147 s.e. 4207 1395 d.e. N. Braun, U. Cologne Ch. Hinke, TUM

  17. SM calculation ●gds LSSM t=1,5 (FN) in comparison to ●truncated to 1p1h in any orbit in model spaces ●pgdg: pνp3/2f5/2p1/2g9/2d5/2g7/2 ●pgndg: pνp3/2f5/2p1/2g9/2nd5/2g7/2 with TBME from OXBASH package (SNA+GF) and SPE tuned to 100Sn 4157

  18. 100Sn core excitation in 98Cd • LSSM smoothly converged at t=5 • 100Sn neutron shell gapN=50 inferred • 6.46 (15) MeV • remaining E2,E4 deficiency is due to • interaction and/or proton gap Z=50 • effective E2 charge will • not help ! pairing E2 ph states pg9/2-2ng9/2-t (d5/2,g7/2)t E4 • Valence excitation energy • increases with t • ph excitation energy • decreases with t • Exception t=2 : pairing • overbinds valence states preliminary ! E2 Valence states pg9/2-2

  19. Ordering of the SP states in 101Sn? Argonne-Oak-Ridge polemic

  20. Core excitation in 97Ag No possibility for shell gap measurement? 58Ni + 45Sc -> 103In* -> 97Ag + 1a2n M. Palacz et al., preliminary results EUROBALL 2003 17/2-

  21. Tf<1 ms known new Counts Eg[keV] Tf[ms] R. Grzywacz et al. PRC 55 (1997) 1126 96Ag 4000 Eg[keV]

  22. DTc< 1 ms; E>4MeV have Tf<1 ms gate 4168 keV gate 470 keV DTc< 0.2 ms 470 668 96 Counts Eg[keV] Eg[keV] 96Ag Counts

  23. 96Ag 0.27(14) ms 4168 SE: 4168 - 511 4264 1.58(3) ms 78(8) ms

  24. 96 Ag 47 49 E[MeV] GF: model space: (g9/2, p1/2) interaction: R.Gross and A.Frenkel,NPA 267(1976)85→ 13-, 15+ isomers Shell Model Calculations: H.Grawe fpg: GF + 1p1h excitation from f5/2 and p3/2

  25. 96Ag and 94Pd

  26. Need for LSSM T = 0 M. Górska et al., ZPA353,233(95) M. La Commara et al., NPA708,167(02) I. Mukha et al., PRC 70,044311(04) C. Plettner et al., NPA733,20(04)

  27. 96 Ag 47 49 Shell Model Calculations: H.Grawe fpg: GF + 1p1h excitation from f5/2 and p3/2 fpndg:fpg + 1p1h excitation from vg9/2 to (g7/2 ,d5/2)

  28. 97CD decay including high spin!! PRELIMINARY!!!

  29. Lipoglavsek et al., PLB 1998 E(6-4) = 48keV B(E2)=3.6 W.u. 6+ isomer in 102Sn 88keV

  30. 5 4 Eg/MeV 3 3 isomers after ToF=200ns decaying within 25 ns ? 2 1 T/ms 0 15 5 20 10 Search for 6+ isomer in 100Sn Eg/MeV

  31. 100,102Sn ß+/EC decay Ip = 6+ isomerism Decay scheme (shell model) 10050Sn50 1969+D 1969 1472 Decay scheme M. Karny et al. EPJA 27, 129 (2006) GT 10250Sn52 M1 GT E2 M1 conversion 10049In51 10249In53

  32. T. Faesterman et al., to be published

  33. T. Faesterman et al., to be published

  34. T. Faesterman et al., to be published

  35. T. Faesterman et al., to be published

  36. T. Faesterman et al., to be published B.A. Brown et al. L. Batist et al., EPJA submitted

  37. asymmetry: p-h excitation? N=64 subshell closure? M. Hjorth-Jensen, ν(d5/2g7/2s1/2h11/2), eν = 1e Relativistic Coulomb excitation of nuclei towards 100Sn • 112,108Sn secondary beam with ~150MeV/u • Au – Coulex target 2003 A. Banu, PhD thesis, PR C72, 061305(R) (2005)

  38. From N=Z100Sn to N» Z132Sn -- LSSM vs. SM Truncationlevel t : total number ofph excitations relative to valence configuration B(E2;2+→ 0+) : SM: full neutron space n(g7/2,d,s,h11/2), en=1.0 e p phmissing ! LSSM: proton-neutron space p(g,d,s),n(g7/2,d,s,h11/2), t = 4 ep=1.5 e, en=0.5 e n ph missing ! Z=50 gap must be calculated on the same footing ! Seniority fit SM en=1.0 LSSM de=0.5 Gap reduction vs. B(E2) increase ! • Z=50 shell gap : • Extrapolation • by quadratic fit • of precisedataN ≥ 58 • and • all data including 100Sn • extrapolation

  39. Sn chain: Enhanced B(E2) systematics towards 100Sn GSI RISING P. Doornenbalet al., PRC(R) in print A. Banu et al, PRC 72 061305(R) 2005 J. Cederkäll et al., PRL98, 172501(2007) A. Ekström et al., PRL 101, 012502(2008) C. Vaman et al., PRL 99, 162501(2007), Shell Model: F. Nowacki et al., ν(d5/2g7/2s1/2h11/2), eν = 0.5e, π(g9/2g7/2d5/2d3/2s1/2), eπ = 1.5e πν monopoles tuned to πESPEs and Z=50 shell gap

  40. Enhanced collectivity Te-I-XeB. Cederwall et al.

  41. Importance of the isoscalar neutron-proton interactions for the development of nuclear collectivityB. HADINIA et al. PHYSICAL REVIEW C 72, 041303(R) (2005) Same mechanism as in Sn isitopes?

  42. Summary and conclusions • ●Precision spectroscopy of exotic nuclei near 100Sn • → tuning/extraction of effective NN interaction(mainly monopoles) • ●"Pre"-mass shell gap determination by high-spin core excited isomers (98Cd-> gap in 100Sn) • High spin isomeric (pure) core excited states may serve as SPE info? • valence space corespondence principle for high spin states/isomers/beta decaying isomers (56Fe<->98Cd, ...) • -> global interaction • enchanced collectivity near closed shells

  43. Collaboration: A. Blazhev2, P. Boutachkov1, T. Brock3, N. Braun2, L. Caceres1, K. Eppinger4, T. Faestermann4, J. Gerl1, H. Grawe1, Ch. Hinke4, M. Hjorth-Jensen5 A. Jungclaus6, Z. Liu7, G. Martínez-Pinedo1,B.S. Nara Singh3, R. Krücken4, F. Nowacki8, S. Pietri1, M. Pfützner9, Zs. Podolyak10, P.H. Regan10, D. Rudolph11, K. Sieja1, R. Wadsworth3, H.J. Wollersheim1 for the Rising collaboration 1GSI Darmstadt, Germany 2IKP, University of Cologne, Germany 3Department of Physics, University of York, UK 4Physics Department E12, TUM, Germany 5Oslo University, Norway 6Universidad Aut´onoma de Madrid, Spain 7University of Edinburgh, Edinburgh, UK 8 IPHC Strasbourg, France 9IEP, University of Warsaw, Poland 10Department of Physics, University of Surrey, UK 11Department of Physics, Lund University, Sweden

More Related