Bogdan Fornal Institute of Nuclear Physics, Polish Academy of Sciences Krakow, Poland Collaboration: IFJ PAN Krakow - ANL Argonne - ANU Canberra The Nuclear Structure Workshop at the Weizmann Institute, April 11-12, 2011, Rehovot, Israel Outline How to access excited structures in the neutron-rich nuclei lying „south” of 208Pb • • deep-inelastic reactions fragmentation reactions 208Pb New yrast structures in nuclei located „south” of Empirical shell model calculations around 208Pb and the comparison with experiment for nuclei below 208Pb Realistic Vlow-k shell model calculations in the vicinity of 208Pb and their predictive power Perspectives for the spectroscopic studies „south-east” of 208Pb How to access YRAST states in neutron-rich nuclei south of 208Pb Experimental techniques used to access YRAST states in neutron-rich nuclei near 208Pb deep-inelastic processes occurring during heavy- ion reactions • prompt gamma-ray spectroscopy • isomer gamma-ray spectroscopy fragmentation reactions at intermediate energies • isomer gamma-ray spectroscopy Deep-inelastic heavy-ion reactions – a tool for gamma-ray spectroscopy of neutron-rich nuclei γ-ray array (e.g.,GS, GASP, EUROB.,AGATA) γ-ray array + magnetic spectr. e.g., CLARA+PRISMA, EXOGAM+VAMOS Experimental technique that we used to access YRAST states in neutron-rich nuclei around 208Pb: γ-ray spectroscopy of deep-inelastic reaction products following the reactions 208Pb+238U or 48Ca+238U 208Pb 48Ca + 238U + 238U ine l on i t ra 238 U b i l + i qu 208 Pb e Z N/ for ine l on i t a 8U ibr +23 l i qu 48 Ca e r Z N/ fo 238U 208Pb 48Ca Product distribution in deep-inelastic reactions of 48Ca 208Pb+238U and 48Ca+238U + 238U N/Z equilibration line for 48Ca+238U N/Z equilibration line for 208Pb+238U 208Pb + 238U The level scheme of 203Hg from the 48Ca + 238U reactions studied by using γ−γ−γ coincidence thick-target technique with GAMMASPHERE Spectrum gated on gamma rays below the isomer in 209Tl using the thick-target GAMMASPHERE data from 208Pb+238U reaction from GAMMASPHERE at Argonne from RISING at GSI N. Al-Dahan et al., Phys. Rev. C. 40, 061302(R) (2009). The nuclei around 208Pb, produced in deep-inelastic reactions 48Ca+238U and 208Pb+238U, in which we have identified yrast structures by using γ−γ−γ coincidence thick-target technique with GAMMASPHERE 48Ca + 238U Po 211 Bi 208 Pb Tl 204 205 Hg 203 204 210 211 210 211 209 206 208 208Pb + 238U Results on the most neutron-rich nuclei around 208Pb produced in the 208Pb + 238U reaction and studied by using the γ−γ−γ coincidence thick-target technique with GAMMASPHERE 210 211 209 206 206Hg B. Fornal et al., Phys. Rev. Lett. 87 (2001) 210Pb G. Lane et al., Nucl. Phys. A682 (2001) 208 211Pb G. Lane et al., Phys. Lett. B (2005) 209Tl 208Hg B. Fornal et al., Proc. Vietri Conf. (2010) Results on neutron-rich nuclei around 208Pb produced in the 48Ca + 238U reaction and studied by using the γ−γ−γ coincidence thick-target technique with GAMMASPHERE 204 205 203 204 203Hg B. Szpak et al., submitted to Phys. Rev. C 204Hg G. Lane at al.., in preparation. 205Tl J. Wrzesinski et al., Eur. Phys. J. A (2004) The modified Kuo-Herling empirical interaction For spin-parity assignments we used as a guidance the results of shell model calculations with the „modified” Kuo-Herling interaction in the configuration space Z<82 and N<126. We modified the original Kuo-Herling interaction in order to account for: • recent revison of the 207Tl mass; • recently located yrast states in 204Pt, 205Au, 205Pb, 206Pb, 206Tl, 206Hg. Comparison between the experiment and results of calculations with the modified Kuo-Herling interaction for magic neutron-hole or proton-hole nuclei lying near 208Pb 204 205 206 206 205 204 203Hg Spin-parity assignments based on the comparison with the modified Kuo-Herling shell model calculations Kuo-Herling modified experiment 203 203Hg Comparison between the experiment and results of calculations with the modified Kuo-Herling interaction for neutron-hole proton-hole Hg isotopes Mapa nuklidow 203 204 205 206 Spin-parity assignments based on the comparison with the modified Kuo-Herling shell model calculations for nuclei lying „east” and „south-east” of 208Pb 210 211 209 208 Realistic shell model calculations using a Vlow-k approach – a theoretical framework for microscopic shell-model calculations starting from the free nucleon–nucleon potential M.Hjorth-Jensen, T.T.S.Kuo, E.Osnes, Physics Reports 261, 125-270 (1995). A.Covello, L.Coraggio, A.Gargano, N.Itaco, Prog. Part. Nucl. Phys. 59, 404 (2007). L.Coraggio, A.Covello, A.Gargano, N.Itaco, T.T.S Kuo Prog. Part. Nucl. Phys. 62, 135 (2009). S.K. Bogner, R.J. Furnstahl, A. Schwenk Prog. Part. Nucl. Phys. 65, 94 (2010). To get the Vlow-k effective interaction we used: Computational Environment for Nuclear Structure (CENS) Authors: T. Engeland, M.Hjorth-Jensen and G.R. Jansen Reference article: M.Hjorth-Jensen, T.T.S.Kuo, E.Osnes, Physics Reports 261, 125-270 (1995) CD-Bonn potential, Λ=2.2 fm-1, model spaces: (Z=50-82, N=82-126) , (Z=50-82, N=126-184) For shell-model calculations we used: computer code OXBASH, B. A. Brown, A. Etchegoyen, W. D. M. Rae, N. S. Goldwin, W. A. Richter, C. H. Zimmerman, W. E. Ormand, and J. S. Winfield, MSU-NSCL Report No. 524, 1985. s.p.s. energies from experiment; for Z≤82 and N≤126 the TBME’s multiplied by (132/208)1/3 Comparison between the experiment and realistic Vlow-k shell model calculations for the magic neutronhole or proton-hole nuclei lying near 208Pb 204 205 206 206 205 204 Comparison between the experiment and realistic Vlow-k shell model calculations for neutron-hole proton-hole Hg isotopes 203 204 205 206 Comparison between the experiment and realistic Vlow-k shell model calculations for nuclei lying „east” and „south-east” of 208Pb 210 211 209 208 204 205 206 210 211 209 203 204 205 206 205 204 208 Perspectives for accessing neutron-rich nuclei near 208Pb by using a radioactive beam of 132Sn ine l on i t ra 238 U b i l ui 8 b+ q e 20 P Z N/ for Let’s consider reactions: 208Pb 132Sn + 208Pb ine l on b i t ra 208 P b i l ui n + q e 2S Z r 13 / N fo + 238U Deep-inelastic reaction 132Sn + 208Pb at Ebeam=750 MeV with an intermediate-thick target The kinematics is favorable for stopping Pb-like neutron-rich nuclei in the target 206Au 131I Conclusions and Outlook Gamma-ray spectroscopic studies with deep-inelastic reactions provide means for accessing yrast structures in nuclei located south of doubly magic 208Pb. New yrast structures identified in 203,204,206,208Hg, 205,209Tl and 210,211Pb form a very good testing ground for the Vlow-k realistic shell model calculations in the regions of neutron-rich nuclei. Calculations with the Vlow-k realistic interaction around 208Pb provide a good description of yrast states in the Z=82 Pb isotopes, N=126 isotones and nuclei with Z<82 and N>126. It is less satisfactory for the nuclides from the region Z<82 and N<126 (having neutron and proton holes) Collaborators B. Szpak, K.H. Maier, R. Broda, W. Krolas, T. Pawlat, J. Wrzesinski, B. Fornal IFJ PAN Krakow, Poland R.V.F. Janssens, S. Zhu, M.P. Carpenter, D. Seweryniak et al. ANL Argonne, USA G. Lane, G. Dracoulis et al. ANU Canberra, Australia
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