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Nuclear Structure and Exotic Decays; Doubly-Magic 56Ni and Semi-Magic 58Ni

Författare:
  • Emma Johansson
Publiceringsår: 2009
Språk: Engelska
Sidor:
Dokumenttyp: Doktorsavhandling

Sammanfattning

The nuclear structure of two nuclei, 56Ni and 58Ni, has been studied using fusion-evaporation

reaction experiments. The experiments were performed at the Lawrence

Berkeley and Argonne National Laboratories in the U.S.A.



The number of known spherical and deformed states in 56Ni has been

significantly extended. One case of prompt proton emission from a

well-deformed excited state into the ground state of 55Co was established. The spherical excited states were interpreted within the

spherical shell model, revealing a good agreement between theory and

experiment, with one notable exception for the yrast and yrare 8+ states. The

deformed states were interpreted using Cranked Nilsson-Strutinsky

calculations, again with very accurate results.



A similar investigation was performed for 58Ni, resulting in one of the

most extensive level schemes known for nuclei. High-spin states including

several rotational bands were found, and a significant number of

spherical and normally deformed states were also discovered. The rotational

bands were interpreted through Cranked Nilsson-Strutinsky calculations,

which allowed the configurations of the bands to be determined. The

normally deformed states of 58Ni were investigated with spherical

shell-model calculations, using two different interactions. The

results are in general satisfactory. The results indicate, however,

that further improvements of the theoretical calculations demands an

increase of the number of

subshells, allowed in the effective interactions.

A total of 12 prompt proton decays and two prompt alpha decays were

discovered in 58Ni. This is the

highest number of known particle decays of this type for any nucleus,

to date. New aspects of the proton decays have been observed, for

instance, two cases of in-band decays and two levels which decay with

competing proton, alpha, and gamma branches.

Disputation

2009-01-23
13:15
Sal B, Fysiska instutionen
  • Alison Bruce (Professor)

Nyckelord

  • Subatomic Physics
  • Doubly magic
  • semi magic
  • 56Ni
  • 58Ni
  • high-spin states
  • fusion-evaporation reactions
  • cranked Nilsson-Strutinsky calculations
  • shell-model calculations
  • prompt proton decay
  • prompt alpha decay

Övriga

Published
  • Nuclear Structure-lup-obsolete
  • Dirk Rudolph
  • ISBN: 978-91-628-7679-1

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