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Multinucleon transfer reactions in the 40 Ar+ 208 Pb and 36 S+ 208 Pb systems

Multinucleon transfer reactions in the 40 Ar+ 208 Pb and 36 S+ 208 Pb systems. F. Haas, S. Courtin et al., IPHC, Strasbourg R. Chapman et al., University of Paisley S. Szilner et al, RBI, Zagreb L. Corradi, A. Stefanini et al., LNL, Legnaro. Our collaborations with LNL. Early steps:

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Multinucleon transfer reactions in the 40 Ar+ 208 Pb and 36 S+ 208 Pb systems

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  1. Multinucleon transfer reactions in the 40Ar+208Pb and 36S+208Pb systems F. Haas, S. Courtin et al., IPHC, Strasbourg R. Chapman et al., University of Paisley S. Szilner et al, RBI, Zagreb L. Corradi, A. Stefanini et al., LNL, Legnaro

  2. Our collaborations with LNL Early steps: Entrance-channel effects in the 58Ni+60Ni fusion reaction GASP experiment, at/below the Coulomb barrier (CB). Measurement of spin distributions Collab. A. Stefanini, D. Ackermann. S. C. et al. Acta Phys.Pol. B30, 1549 (1999) , S.C. et al. Nucl.Phys. A724, 125 (2003) S.C. et al. 55. Nucl.Phys. A722, 190 (2003). Collaboration very active since then (A. Stefanini et al.) Fusion below CB/ down to deep subbarrier energies : from enhancement of fusion at CB to fusion hindrance effects at deep subbarrier energies (supported by the LEA) 15 publications, recently 40,48Ca + 40,48Ca (down to 20 mb) … N-rich nuclei, transfer reactions …

  3. Multinucleon transfer reactions • Deep inelastic à la Broda • (J. Phys. G 32 (2006) R151) • E > ECB • ‘damped collisions, dissipative collisions, quasi-fission, multi-particle transfer’ • Choice target and projectile, N-rich regions (out of reach for fusion-evaporation). • Thick targets / Doppler effect / T > 1ps • Complex spectra (several binary reaction channels), high spins • Challenging experiments Structure of the projectile-like fragments on heavy targets, N/Z

  4. First experiments Strasbourg / Paisley Deep inelastic, 37Cl (234 MeV) + 160Gd (thick) EUROBALL IV / Vivitron N-rich isotopes of Dy (high spin states) and N-rich Cl and S isotopes 36S (Z = 16, N=20) spectra / double gates / yrast line extended to 6+ / sdfp SM calc. 1st observation of the yrast sequence of 41Cl (Z=17, N=24)) Clean spectra, Doppler corrected … X. Liang et al., Phys.Rev. C66, 037301 (2002) X. Liang et al., Eur.Phys.J. A 10, 41 (2001)

  5. LNL After the Euroball campaign PRISMA CLARA W = 80 msr (x,y,t) MCP (x’,y’,t’) MWPPAC MCP – PPAC: TOF (DE,E) IC Z, A, q, clean identification of the fragments (velocity) 25 Compton-suppressed Ge Clovers e = 3% for single 1 MeV g

  6. Structure of N-rich S, Si, P, Cl isotopes Cl S P • 36S (215 MeV) + 208Pb • Prisma (grazing – 56°) + Clara • 208Pb (300 mg.cm-2), C backing • Detection of projectile-like fragments • in Prisma : Na (Z=11) to Mn (Z = 25) Si Al X. Liang et al., Phys.Rev. C 74, 014311 (2006)

  7. 36S + 208Pb Mass spectra N=20 Z.M. Wang et al., Phys.Rev. C 83, 061304 (2011) D. O’Donnel et al., Phys.Rev. C 81, 024318 (2010) Z.M. Wang et al., Phys.Rev. C 81, 054305 (2010) Z.M. Wang et al., Phys.Rev. C 81, 064301 (2010) A. Hodsdon et al., Phys.Rev. C 75, 034313 (2007) X. Liang et al., Phys.Rev. C 74, 014311 (2006)

  8. 36S + 208Pb Experimental Shell Model Experimental 38Cl (Z=17,N=21)/ sdpf SM calc. ‘Poves-Nowacki int.’ D. O’Donnell et al., Phys.Rev. C 81, 024318 (2010) Yrast sequence of 36Si (Z=14, N=22) extended/ sdpf SM calc. Near spherical, X. Liang et al., Phys.Rev. C 74, 014311 (2006) Experimental Shell Model Experimental Shell Model 37P (Z=15, N=22) (previous exp. revisited) 1 g-ray known previously / sdpf SM calc. Improved ‘Poves-Nowacki int.’A. Hodsdon et al., Phys.Rev. C 75, 034313 (2007) 33Si (Z=14, N=19) : intruder negative parity band / 1w PSDPF int. SM calc. Z.M. Wang et al., Phys.Rev. C 81, 064301 (2010)

  9. sdnuclei and the Shell Model • For the description of the positive parity sd states, the remarkable success • obtained by the ‘Universal SD’ interaction of Wildenthal and Brown • 16O core, nucleus in the sd shell, a 0winteraction • For the description of the negative parity sd states, no interaction existed to • describe these states throughout the sd shell. Such an interaction has been built in • Strasbourg. • 4He core, nucleons in the p, sd and fp shells with one jump possible between the p • and sd shell or between the sd and fp shell. • This is a full 1winteraction

  10. The new 1wPSDPF interaction Building blocks : the 0w CK (Cohen-Kurath) interaction for the p shell the0w USDB interaction (Brown) for the sd shell the0wSDPF interaction (Nowacki-Poves) for the sdpf shells the two body cross matrix elements p → sd and sd → pf were obtained through a fitting procedure on negative parity states at the beginning and end of sd (Antoine) More details in : M. Bouhelal et al, Acta Physica Pol. B 40 (2009) 639 M. Bouhelal et al, Eur. Phys. J. A 42 (2009) 529. M. Bouhelal et al, Nucl. Phys. A 864 (2011) 113. Not only the energy spectra but also the electromagnetic transitions (Nathan) M1, E2 for transitions + → + or - → - E1, M2, E3 for transitions + → -

  11. Applications of the PSDPF interaction • the negative parity and deformed bands in the Ne and Na isotopes • the ‘collective’ 3- states throughout • in the second half of the shell, the long lived negative parity states from the deep • inelastic reactions • the negative parity intruder states in the N = 20 isotones 34Si, 35P • and 36S : energy spectra and electromagnetic transitions • In general, the evolution in energy of the 0p, 1p-1h, 2p-2h, 3p-3h ... states as a • function of Z and N for sd nuclei.

  12. Chart of sd nuclei with known negative parity states

  13. Results from the Prisma+Clara experiment 36S on 208Pb and PSDPF (1 ħw) SM calculations 11/2- 5241 9/2- 5089 5379 9/2- 4892 5153 7/2- 4754 7/2- 4186 3976 4971 4839 4293 4254 p above d5/2 n hole in 1d3/2 n in f7/2 4790 3335 4379 2553 35P 34Si 36S

  14. 40Ar + 208Pb @ LNL 40Ar (255 MeV/ALPI) + 208Pb (300mg.cm-2) Prisma @ 54° Neutron-rich Ar(Z=18) and K(Z=19) isotopes 41Ar (+1n) 11/2-, new 40Ar 2+ x 1n in f7/2 42Ar (Z=18, N=24) (+2n) 2+, 11/2-, Argon isotopes S. Szilner et al., Phys. Rev. C 84, 014325 (2011)

  15. 36S + 208Pb @ LNL Lifetimes 11/2- 5241 4.3 ps 9/2- 5089 4.8 ps 5379 34.1 ps 9/2- 4892 1.2 ps 5153 1.3 ps 7/2- 4754 5.0 ps 7/2- 4186 54.1 ps 3976 21.7 fs 4971 4839 0.82 ps 4293 0.25 ps 4254 147 ps 4790 8.1 ps 3335 76.7 fs 4379 40.1 fs 2553 0.17 ps t> 1 ps RDDS method 34Si 35P 36S

  16. 36S + 208Pb @ LNL AgataD - Prisma + Plunger, June 2011 Experimental conditions as close as possible to the Prisma-Clara experiment Agata 208Pb, Nb backing + Nb degrader Nb chosen after in beam tests AgataD – 1st exp. with 5 clusters Prisma @ 59° (±6°) The Köln Plunger

  17. 36S + 208Pb @ LNL AgataD - Prisma + Plunger Z=16 Z=15 Z=17 N=20 +1p,±xn Z=14 0p,±xn -1p,±xn q=15+ q=14+ q=13+ q=12+ -2p,±xn Z = 16 A. Goasduff et al.

  18. 3290 keV Preliminary A. Goasduff et al. Results, lifetimes, next LEA meeting …

  19. Next … • Fusion reactions far below CB, influence of the neutron excess / LNL electrostatic deflector • Multinucleon transfers / pairing : • PRISMA • Structure (of N-rich …) • Galileo (Ge Clusters / Gasp detectors), C. Ur et al. F. Haas, S. Courtin et al., IPHC, Strasbourg R. Chapman et al., University of Paisley S. Szilner et al, RBI, Zagreb L. Corradi, A. Stefanini et al., LNL, Legnaro

  20. AgataD / Counting rate tests for Plunger experiments

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