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Down and Up Along the Proton Dripline

Down and Up Along the Proton Dripline. Heavy One-Proton Emitter Light One-Proton Emitter Light Two-Proton Emitter Heavy Two Proton Emitter. 40. Centrifugal (l=5). 20. Coulomb. V (MeV). 0. 40. 20. Radius (fm). -20. Nuclear. -40. -60. Proton Radioactivity. 151. Lu. 71. 80. 20.

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Down and Up Along the Proton Dripline

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  1. Down and Up Along the Proton Dripline Heavy One-Proton Emitter Light One-Proton Emitter Light Two-Proton Emitter Heavy Two Proton Emitter

  2. 40 Centrifugal (l=5) 20 Coulomb V (MeV) 0 40 20 Radius (fm) -20 Nuclear -40 -60 Proton Radioactivity

  3. 151 Lu 71 80 20 l=5 E=1.25 MeV V (MeV) 0 40 80 60 20 Radius (fm) -20 T1/2(l=0) = 3ms l=0 T1/2(l=5) = 81ms -40 Strong Influence on Angular Momentum

  4. Heavy Proton Emitter • Long lifetimes due to Coulomb and angular momentum barrier • Produce in fusion evaporation reactions or fragmentation • Separate and subsequently stop in a detector for identification • Use segmented silicon strip detectors for a delayed decay

  5. 1p Separation Energies (Odd p-numbers) T. Radon et al., Pramana 53 (1999) 69

  6. 1p Separation Energies (Even p-numbers) T. Radon et al., Pramana 53 (1999) 69

  7. Structure and Deformed Emitters J. Uusitalo et al. 155Ta T. N. Ginter et al. 150Lu A. A. Sonzogni et al. 131Eu, 141Ho, 145Tm K. S. Toth et al. 151Lu C. J. Gross et al. 113Cs K. Rykaczewski et al. 140Ho,141Ho P. J. Woods and C. N. Davids, Annu. Rev. Nucl. Part. Sci. 47 (1997) 541

  8. Q-Values and Branching Ratios 167Ir 161Re C. N. Davids et al., Phys. Rev. C 55, (1997) 2255 R. J. Irvine et al., Phys. Rev. C 55 (1997) R1621

  9. Where is the Proton Dripline?

  10. “Short”-Lived Proton Emitters C.R. Bingham et al.

  11. 100Sn K. Sümmerer et al., Nucl. Phys. A616 (1997) 341c

  12. rp - Process Mo 83 84 B. Blank, J. Phys. G 24 (1998) 1385 Nb 81 82 83 Zr 79 80 M. F. Mohar et al., Phys. Rev. Lett. 66 (1991) 1571 B. Blank et al., Phys. Rev. Lett. 77 (1996) 2893 49 50 51 52 53 Co 50 51 52 Fe 45 46 47 48 49 50

  13. New Isotopes Along the Dripline B. Blank et al., Phys. Rev. Lett. 77 (1996) 2893 B. Blank, J. Phys. G 24 (1998) 1385

  14. Prompt Decay from a Well-Deformed Band p g D. Rudolph et al., Phys. Rev. Lett. 80 (1998) 3018

  15. 52 26Fe26 53 26Fe27 First Proton Radioactivity (19/2-) 12 3.19 247 ms 0.84 2+ 1.5% 0 0+ 10 b+ (7/2-) 0 8 53 27Co26 Energy (MeV) 6 4 19/2- 3.04 2 0 7/2- 0 Joseph Cerny and J. C. Hardy, Annu. Rev. Nucl. Part. Sci. 27 (1977) 333

  16. b-Delayed Proton Emitters S. Czajkowski et al., Nucl. Phys. A628 (1998) 537

  17. Light Proton Emitter • (Very) short lifetimes due to small Coulomb and no or very small angular momentum barrier (l=0,1,2) • Produce in transfer reactions or fragmentation • Identify by complete kinematic reconstruction in flight

  18. 151Lu and 12O

  19. Definition of Radioactivity “…should lead to lifetimes longer than 10-12 sec, a possible lower limit for the process to be called radioactivity.” Joseph Cerny and J. C. Hardy, Annu. Rev. Nucl. Part. Sci. 27 (1977) 333

  20. Search for Di-Proton Emitters • Predicted by Goldansky in 1960 • Until recently (?) elusive • In-Flight Decay (Short lifetimes) • Ground State • Excited States • Resonance Scattering • Coulomb Excitation • Neutron-Stripping • Implantation/Decay (Long lifetimes) • Beta-Delayed Emitters • Ground-State Emitters

  21. Potential Two Proton Emitter

  22. 11N+p 12O 10C+2p 11N+p 11N+p 12O 12O 10C+2p 10C+2p 12O 12O 11N+p 10C+2p 10C+p+p 10C+p+p Definitions Di-Proton Decay Simultaneous Decay Sequential Decay 12O 10C+p+p

  23. Three Body Model L. V. Grigorenko et al., Phys. Rev. Lett. 85 (2000) 22

  24. Three-Body Decay Paths L. V. Grigorenko et al., Phys. Rev. Lett. 85 (2000) 22

  25. Light Two-Proton Emitters

  26. Two-Proton Decay of 6Be (2+) 1.67 (3/2-) 0.59 (0+) g.s. 5Li+p 6Be -1.37 4He+2p D.F. Geesaman et al., Phys. Rev. C15 (1977) 1835

  27. Transfer Reactions with Radioactive Beams

  28. Production and Identification of short-lived Nuclei

  29. Decay Energy Spectrum of 12O EDecay = 1.77 MeV G = 575 keV

  30. Two-Proton Angular Distribution Di-Proton Sequential

  31. 11N+p 12O 10C+2p 12O 11N+p 10C+p+p Decay Width Sequential Decay However: Γcalc 10 keV Γmeasured = 575 keV

  32. Elastic Resonance Scattering L. Axelsson et al., Phys. Rev. C 54 (1996) R1511

  33. Ground State of 11N A. Azhari, et al. Phys. Rev. C57, 628 (1998) J. M. Oliviera, et al. Phys. Rev. Lett. 84, 628 (2000) K. Markenroth, et al. Phys. Rev. C62, 034308 (1998) 1.45 MeV 1.63 MeV 1.27 MeV 11N

  34. Two Proton Decay of 12O Old 2.0 MeV 1.8 MeV ?? New 1.8 MeV ~1.5 MeV 11N+p 12O 10C+2p

  35. Di-Proton Decay of 16Ne? L. V. Grigorenko et al., Phys. Rev. Lett. 88 (2002) 042502

  36. New Shell Structure? ?? Z=8 N=20 N=16 ? N=8

  37. Vanishing of the Proton Z=8 Shell ? Z=8 5Li – 9B – 13N – 17F 7B – 11N – 15F 11N (-1.92MeV)

  38. Vanishing of the Proton Z=8 Shell ? 15F ?? 11N (-1.27MeV)

  39. Mass of 15F ?? 15F ?? 11N

  40. Previous 15F Measurement Binding Energy of 15F : –1.47 MeV  = 1 MeV G. J. KeKelis et al., Phys. Rev. C 17, 1929 (1978)

  41. Theoretical Prediction S. Grevy, O. Sorlin, and N. Vinh Mau, Phys. Rev. C56 (1997) 2885

  42. 2% 87% 11% Invariant Mass Measurements at GANIL • Primary Beam: 24Mg • Secondary Beams:20Mg, 18Ne, 17F • Fragments Energies:35-43 MeV/nucleon • Stripping Reactions • Detectors:SPEG SpectrometerMUST array

  43. 15F  14O + p Relative to KeKelis et al.  Binding Energy of 15F : Egs = –1.00  0.08MeV  = 1.23  0.22MeV T. Zerguerras et al., to be published

  44. Mass of 15F !! 15F !! 11N

  45. Two Proton Decay of 16Ne Old 15F 1.5 MeV 1.4 MeV ?? New 1.4 MeV 1.0 MeV 15F+p 16Ne 14O+2p

  46. Two Proton Decay of 19Mg ?? Theoretical Predictions ~1.8 MeV • Masses of 19Mg and 18Na are not known • Stripping reactions:20Mg  18Na  17Ne + p20Mg  19Mg  17Ne + 2p ~1.2 MeV ?? 19Mg 18Na+p 17F+2p

  47. First Measurement of the Mass of 18Na  Binding Energy of 18Na : Egs = –0.411  0.05 MeV  = 0.34  0.09 MeV • No events observed for20Mg  19Mg  18Na + 2p

  48. Decay of 19Mg Sequential ?? • Two-Proton Decay will most likely be sequential.. • .. unless the mass of 19Mg is also underpredicted • Measure the mass of 19Mg ~1.2 MeV 0.41 MeV 19Mg 18Na+p 17F+2p

  49. Intermediate (1p) Nuclei

  50. 9.72 3.51 3/2+ 2+ 2He 7.77 Sequential 0+ 0 6.59 2.37 1/2+ 12C+2p 5.17 13N+p 6.57 4.63 0+ 14O Two-Proton Decay of 14O* C.R. Bain et al., Phys. Lett. B373 (1996) 35

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