1 / 14

Study of neutron-deficient nuclei below 100 Sn

“ Universa Universis Patavina Libertas ”. Study of neutron-deficient nuclei below 100 Sn. A. Gottardo, J.J. Valiente-Dobon,…. Physical motivations Experimental details. Introduction.

brooke-levy
Download Presentation

Study of neutron-deficient nuclei below 100 Sn

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. “Universa Universis Patavina Libertas” Study of neutron-deficient nuclei below 100Sn A. Gottardo, J.J. Valiente-Dobon,… • Physical motivations • Experimental details

  2. Introduction The evolution of nuclear structure at the extremes of isospin is one of the major topics in modern nuclear physics The proton-rich nuclei close to the N = Z line below mass 100 are known to exhibit a variety of interesting phenomena: 1p and 2p radioctivity and higher-lying spin-gap isomers Spin-gap and seniority isomers Two-proton radioactivity in 94Ag Rp-process

  3. 94Ag (1) This N = Z nucleus has two isomers (7+, 21+,t1/2 ~ 0.5 s), with the highest one decaying via one and two-proton emission Nature,439, 298 (2006) The 2p radioactivity strength suggest a very deformed (3:1) 21+ isomer The 21+ isomer also decays by two different 1p emission PRL 95, 022501 (2005)

  4. 94Ag (2) PRC 77, 064304 (2008) Mass measurements, detailed γspectroscopy of the daughter nucleus and following experiment did not confirm the 2p emission… further studies needed The γspectroscopy of 94 Ag will provide valuable information on nuclear structure in this N =Z nucleus, in particular clarifying the structure above the proton-emitting isomer. T= 0 aligned pairing?

  5. 96Cd The 100Sn nucleus is a fundamental step in uderstanding the nuclear force and the nuclear structure The isotopes below 100Sn, with protons and neutrons filling the g9/2 shell up to N,Z = 50, are crucial to infer the evolution of nuclear structure towards the shell closure A 16+ spin-gap isomer is predicted and decay spectroscopy has been performed at GSI (FRS-Rising) It is fundamental to also have prompt-spectroscopy data! Acta Phys. Pol. B, 40, 611 (2009)

  6. 100In 100In is a 1p-hole – 1n-particle nucleus with respect to 100Sn: ideal case to study pn interaction In prompt spectroscopy we expect to see states from the πg9/2-1-νd5/2 and πg9/2-1-νg7/2 multiplets, and perhaps excitations of the 100Sn core for spins higher than 8+ Direct extraction of pn matrix elements PRC 65, 021302(R) (2002))

  7. 101Sn 101Sn is fundamental nucleus in shell model, being one neutron above 100Sn: ideal case to study the double shell closure and the effect of tensor interaction States from νd5/2 and νg7/2, νh11/2 are expected, together with the excitation of the 100Sn core Ongoing discussion on the inversion of νd5/2 and νg7/2, linked to tensor force PRL 105, 162502 (2010))

  8. How to study these nuclei? Fusion evaporation- reactions: proton-rich, high spin population • Channels with evaporation of 3 neutrons: 3n, 1p3n… • Channels with evaporation of 2 neutrons: 2n, 1p2n… Gamma array: Agata, Galileo, Exogam2 Charged particles: Diamant, Trace Neutron array: Neda

  9. Batch mode for exotic beams Irradiation of a target to produce 56Ni Primary proton beam from cyclotron: 70MeV, 0.8 mA The target then becomes the source of the LNL TANDEM Fusion-evaporation reaction with NEDA – TRACE – AGATA/GALILEO

  10. 94Ag 40Ca + 58Ni p3n evaporation 40Ca + 56Ni p1n evaporation Cross section ~ 50 μb Cross section ~ 100 μb Beam current ? Beam to be produced in batch mode at LNL-SPES Beam current > 10 pnA Three – neutron detection efficiency ~ 0.1% One – neutron detection efficiency ~ 25%

  11. 94-96Cd 40Ca + 58Ni 2n-3n evaporation (95-96Cd) 40Ca + 56Ni 1n?-2n evaporation (94-95Cd) Cross section ~ 100 μb - 6 μb Cross section ~ 150-9 μb Beam current ? Beam to be produced in batch mode at LNL-SPES Beam current > 10 pnA Three – neutron detection efficiency ~ 0.1% Two – neutron detection efficiency ~ 5%

  12. 100In 58Ni + 45Sc 3n evaporation 56Ni + 46Ti pn evaporation Cross section ~ 4 μb Cross section ~ 20 μb Beam current ? Beam to be produced in batch mode at LNL-SPES Beam current > 10 pnA Three – neutron detection efficiency ~ 0.1% one – neutron detection efficiency ~ 25%

  13. 101-100Sn 58Ni + 56Ti 3n evaporation:101Sn 56Ni + 56Ti 2n evaporation 100Sn Cross section ~ 4 μb Cross section ~ 10 μb Beam current ? Beam to be produced in batch mode at LNL-SPES Beam current > 10 pnA Three – neutron detection efficiency ~ 0.1% Two – neutron detection efficiency ~ 5%

  14. Conclusions Physics case to study many proton-rich nuclei below A=100: Attempts already done at Argonne with GS-FMA The identification of evaporated neutrons and protons to select the reaction channel is a powerful tool to study exotic nuclei (better efficiency than FMA?) The future avalability of 56Ni beam with the batch-mode technique will enable to study very exotic nuclei exploiting the capabilities of NEDA at full

More Related