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Single-neutron structure of neutron-rich nuclei near 132 Sn

Single-neutron structure of neutron-rich nuclei near 132 Sn. Jolie A. Cizewski Department of Physics & Astronomy Rutgers University. Collaboration RIBENS/Center of Excellence. Rutgers University J.A.C., R. Hatarik, P.O’Malley, Steve Pain , T. Swan

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Single-neutron structure of neutron-rich nuclei near 132 Sn

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  1. Single-neutron structure of neutron-rich nuclei near 132Sn Jolie A. Cizewski Department of Physics & Astronomy Rutgers University

  2. CollaborationRIBENS/Center of Excellence Rutgers University J.A.C., R. Hatarik, P.O’Malley, Steve Pain, T. Swan ORNL D.W. Bardayan, J.C. Blackmon, F. Liang, C.D. Nesaraja, D. Shapira, M.S. Smith Univ. Tennessee K.Y. Chae, Kate L. Jones, Z. Ma, B.H. Moazen Tennessee TechRay Kozub, J.Shriner, D.Sissom ORAU C. Matei University of SurreyJ.S. Thomas Colorado School of MinesK. Chipps,L. Erikson, R.J. Livesay Ohio UniversityA. Adekola Warsaw W. Krolas Funded in part by the U.S. DOE Office of Science & NNSA/SSAA and the National Science Foundation.

  3. Fundamental Questions in Nuclear & Astro Physics • Origin of elements • Limits of nuclear existence • Evolution of shell structure

  4. Measuring (d,p) on Rare Isotopes near Shell Closures HRIBF yields N=82 Neutron magic-number nuclei at waiting points Measure (d,p) reactions with unstable beams • Measure single-neutron energies + spectroscopic strengths • Provide data to understand r process nucleosynthesis

  5. Transfer measurements around 132Sn 124Sn 130Te 131Sn 135Te 133Sn Te Sb Z = 50 Sn In Stable Doubly magic N = 82 Double shell closure Z=50, N=82 132Sn(d,p)133Sn, 130Sn(d,p)131Sn and 134Te(d,p)135Te measurements completed

  6. Energy (MeV) Angle (deg) ds/dW (mb/sr) 30 60 90 120 150 qlab (deg) 132Sn(d,p) kinematics @ 4.7 A-MeV Forward qc-o-m↔ backward qlab At backward qlab cross section very small and Eproton very small. At forward qlab Eproton rises quickly with angle (dE/dq is large). 20 15 10 Want to measure around 90o. 5 0

  7. ORRUBA: Oak Ridge Rutgers University Barrel Array • Flexible design for measuring ejectiles from transfer reactions in inverse kinematics • Resistive and non-resistive Si detectors (1000mm, 500mm and 65mm) • ORRUBA gives ~80% f coverage over the range 47° →132° • 288 electronics channels (conventionally instrumented)

  8. Plan View Beam View ORRUBA telescopes ORRUBA 1000μm 6 x ORRUBA 1000μm 5x5cm2 telescope Beam 5x5cm2 telescopes ORRUBA telescopes ORRUBA 1000μm Beam SIDAR ORRUBA telescopes 132Sn(d,p) detectors

  9. ORRUBA detectors (back angles) SIDAR detectors (back angles) 132Sn(d,p) photo

  10. 1i13/2 Should be strongest in N=82 (d,p) ( =1 and  =3) 3p1/2 3p3/2 2f5/2 2f7/2 1h9/2 82 Two neutron holes in 130Sn80(g.s.) 1h11/2 2d3/2 3s1/2 2d5/2 1g7/2 What should one expect to see?

  11. Only weak evidence for p1/2 state Tentatively assigned f5/2; other candidates at higher energies N=83 Systematics

  12. (11/2-) 3700 14 12 (d,p) to ground state (5/2-) 2004.6 1655.7 (1/2-) 10 1560.9 (9/2-) 853.7 (3/2-) 8 Ep(MeV) (7/2-) 0.0 1.45s 6 (d,p) to 1st ex state 4 (d,p) to 5/2- state 2 (d,p) to 1/2- state ? 0 60 70 80 90 100 110 120 130 140 p (deg) 132Sn(d,p): “all” ORRUBA detectors

  13. 90 ORRUBA detectors 80 Preliminary Fit known levels: g.s., 853.7-keV and 2004.6 keV (p1/2) candidate: Ex= 1390 (40) keV 70 60 Counts g.s 50 40 30 20 10 0 0 20 40 60 80 100 120 140 160 180 Ex (channels) 133Sn Excitation Energy

  14. 134Te(d,p): Q-value spectrum ≈1  MeV (p1/2) ≈0.66 MeV (p3/2) g.s. (f7/2) ≈1.8 MeV (f5/2 ?) 35 30 25 Counts 20 15 10 5 -3 -2 -1 0 1 -4 Q value (MeV) PRELIMINARY: single strip CoM resolution ≈250 keV (FWHM)

  15. N=83 Single Particle Energies • Previously two (unhappy) alternatives: • SPEs straight from experiment i.e. including the p1/2 at 1656 keV. OR • Extract from states in other nuclei e.g. Z=54, 56 isotones • Sakar and Sakar Phys. Rev. C64 014312 (2001). • NOW correct SPE’s • Calculations of masses, other nuclear properties • Nuclear astrophysics

  16. 130Sn(d,p)131Sn N=81 Fwd ORRUBA #1, MCP coinc., narrow TAC window 4679(41) 4018(28) 3417(23) 2680(23) 131Sn* (keV) Energies from 4-6 detectors Calibrations: 132Sn(d,p)133Sn 130Te(d,p)131Te Systematic error: 30 keV 2H(132Sn,p)133Sn Counts (g.s.) Q (keV) PRELIMINARY

  17. Summary: 132Sn(d,p): Confirm 3 previously measured states Populate (p1/2) state (for first time) at Ex=1390(40) keV Better agreement with systematics and theory 134Te(d,p): Candidate for f5/2 at ≈1.8 MeV 130Sn(d,p): States above N=82 gap: “Same” spectrum Ex>2.6 MeV as 133Sn Work in progress: Analysis of all detectors, all experiments Angular distributions To support p1/2 assignment of 1390-keV state in 133Sn For all states populated in 133Sn, 135Te, 131Sn Spectroscopic factors Elastic scattering in forward angle detectors

  18. Thank you Single-neutron structure of neutron-rich nuclei near 132Sn Work supported in part by the U.S. Department of Energy and National Science Foundation

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