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Investigation of discrete states and quasi-discrete features in 150,152Sm via the (p,t) reaction.

Humby, P. (2017) Investigation of discrete states and quasi-discrete features in 150,152Sm via the (p,t) reaction. Doctoral thesis, University of Surrey.

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The (p,t) reaction was used to identify new levels and gamma-ray transitions in 150,152Sm utilising the particle-gamma and particle-gamma-gamma coincidence techniques. The experiment was performed using the STARLiTeR array located at the Cyclotron Institute of Texas A&M University. The relative partial cross sections for the observed levels, angle averaged between 34 and 58 degrees, were measured. A narrow peak-like structure was observed between 2.3-3.0 MeV excitation energy, in between the region of strongly populated discrete states at low energy and the high energy continuum region. In 150Sm, 39(4)% of the strength of the peak-like structure could be accounted for by the observed discrete states, which compares to a value of 93(15)% for 152Sm. The orbital angular-momentum transfer was probed by comparison of the experimental angular distributions to those calculated using the DWBA theory. The experimental angular distributions for the population of the peak-like structures are very similar in the two reactions, and significantly different to both the angular distribution of the background under the structures, and to the distribution obtained from the nearby continuum region at higher excitation energy. Post irradiation, the half-lives of isomeric states in 152Eu, populated in the 154Sm(p,3n) reaction, were obtained by measuring the decrease in intensity of the gamma rays emitted in the decay of these long lived levels. The half-life of the J^pi = 8^- isomer 152m2Eu was measured to be 95.8(4) min, which is a factor of 2.5 reduction in uncertainty compared to the previous literature value of 96(1) min.

Item Type: Thesis (Doctoral)
Subjects : Nuclear Physics
Divisions : Theses
Authors :
Humby, P.
Date : 28 April 2017
Funders : U.S. Department of Energy
Contributors :
ContributionNameEmailORCID, P. H.
Depositing User : Peter Humby
Date Deposited : 05 May 2017 09:16
Last Modified : 31 Oct 2017 19:14

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