Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298152
Title: Spectroscopy of exotic f - p - g nuclei using projectile fragmentation and fusion evaporation reactions
Author: Chandler, Catherine
ISNI:       0000 0000 5917 1964
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1999
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Abstract:
The structural properties of the very neutron deficient systems around N~Z~40 have been studied in two experiments performed at the GANIL and Legnaro laboratories. The fragmentation of a 60 MeV/u92 Mo beam on a natural nickel target at the GANIL Laboratory, France, produced exotic nuclei along the proton drip line in the mass 80 region. Isomeric decays have been observed for the first time in the N=Z+2 systems 74 36Kr, 80 39Y and 84 41Nb. The isomer in 74 Kr is interpreted as the hindered decay from an excited 0+ state, supporting the long-standing prediction of prolate/oblate shape coexistence in this nucleus. Transitions from states below an isomer in the N=Z nucleus 86 43Tc have also been tentatively identified, making this the heaviest N=Z system for which gamma-ray decays from excited states have been observed. Conclusive evidence for the existence of the Z=N+1 isotopes 77 39Y, 79 40Zr and 83 42Mo has also been obtained together with upper limits on the particle decay lifetimes of the odd-proton systems 81 41 Nb and 85 43Tc. The reported instability of the lighter odd-Z, Tz = -1/2 systems 69Br and 73Rb makes the observed existence for 77 39Y particularly interesting. A possible explanation for the relative particle stability of 77 39Y is given in terms of the shape polarising effect of the N=Z=38 prolate shell gap on the nuclear mean field and the increased centrifugal barrier associated with the occupation of a g9/2 proton orbital. The second experiment was performed to further investigate the oblate nature of the isomeric state in 74Kr. The reaction 40Ca(40Ca, alpha2p)74Kr was used at a beam energy of 135 MeV obtained from the Tandem XTU accelerator. The EUROBALL gamma-ray array was used in conjunction with the ISIS charged particle silicon ball to study the states above and below the isomer. The ISIS ball was used to highlight channel selection of non-yrast states by particle gating. No evidence for the 0+2 isomer in 74Kr was observed in this work.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.298152  DOI: Not available
Keywords: MOLYBDENUM 92 REACTIONS; NICKEL; KRYPTON 74; YTTRIUM 80; NIOBIUM 84; ISOMERIC TRANSITIONS; ISOMERIC TRANSITION ISOTOPES; NEUTRON-DEFICIENT ISOTOPES; YTTRIUM 77; DEFORMED NUCLEI; CALCIUM 40 REACTIONS; CALCIUM 40 TARGET
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