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Richter W.A.,IThemba LABS | Richter W.A.,University of the Western Cape | Brown B.A.,Michigan State University
Physical Review C - Nuclear Physics | Year: 2013

We present results for levels in 30S (the mirror nucleus of 30Si) that are used for the 29P(p,γ) rp reaction rate calculations. The resonance energies used in the reaction rate calculations are based on recent measurements which extend the excitation energy spectrum. The levels are checked against results from the isobaric mass multiplet equation and the binding energies of the T=1 analog states. Where the analog states are not known the levels are calculated with two-body interactions that use the sd-shell interactions USDA and USDB as the charge-independent parts, with a Coulomb, charge-dependent, and charge-asymmetric Hamiltonian added. The γ-decay lifetimes and 29P to 30S spectroscopic factors are also calculated with the same interactions, and together with experimental information on the levels of excited states are used to determine the 29P(p,γ)30S reaction rates. © 2013 American Physical Society.


Richter W.A.,IThemba LABS | Richter W.A.,University of the Western Cape | Brown B.A.,Michigan State University
Physical Review C - Nuclear Physics | Year: 2012

We present results for levels in 36K (the mirror of nucleus 36Ar) that are used in rp reaction rate calculations. The levels are also determined from the isobaric mass multiplet equation and the binding energies of the T=1 analog states as a check on the assignment of spins and parity. Where the analog states are not known, the levels are calculated with two-body interactions that use the sd-shell interactions USDA and USDB as the charge-independent parts, with a Coulomb, charge-dependent, and charge-asymmetric Hamiltonian added. The γ-decay lifetimes and 35Al to 36K spectroscopic factors are calculated with the same interactions, and together with experimental information on the levels of excited states, are used to determine the 35Ar(p,γ)36K reaction rates. © 2012 American Physical Society.


Comrie A.C.,University of Cape Town | Buffler A.,University of Cape Town | Smit F.D.,IThemba LABS | Wortche H.J.,INCAS
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2015

Three different digital implementations of pulse shape discrimination for pulses from an EJ301 liquid scintillator detector are presented, and illustrated with neutrons and gamma-rays produced by an Am-Be radioisotopic source, a D-T generator and beams produced by cyclotron-accelerated protons of energies 42, 62 and 100 MeV on a Li target. A critical comparison between the three methods is provided. © 2014 Elsevier B.V. All rights reserved.


Richter W.A.,IThemba LABS | Richter W.A.,University of the Western Cape | Brown B.A.,Michigan State University | Signoracci A.,Michigan State University | Wiescher M.,University of Notre Dame
Physical Review C - Nuclear Physics | Year: 2011

We present theoretical results for the Al25(p,γ)Si26 resonance-capture rate. The isobaric mass multiplet equation is used to determine the energies and Jπ values of states in Si26 based upon those observed in Mg26 and Al26 together with sd shell calculations for the c coefficients. Three Hamiltonians for the sd shell, USD, USDA and USDB, are used to estimate the theoretical uncertainties in the γ-decay and proton-decay widths that go into the resonance-capture rate. © 2011 American Physical Society.


Khenfouch M.,University Sidi Mohammed Ben Abdellah | Baitoul M.,University Sidi Mohammed Ben Abdellah | Maaza M.,IThemba LABS
Optical Materials | Year: 2012

The importance of the white photoluminescence (Pl) with multiple emissions for lighting applications also the attractive optoelectronic properties of graphene and nanostructured zinc oxide (ZnO) are universally known. In this work we present an intense Uv visible blue to red luminescence obtained from our synthesized few layered graphene-zinc oxide (FLG-ZnO) based nanostructures prepared via a sol-gel method using ZnO precursors and a FLG solution. Significant blue-green, yellow-orange moreover, red emissions, from FLG-ZnO deposited on a normal glass substrate, generate a clear white luminescence by their recombination and across the entire visible spectrum. While, to investigate the nanostructure of this system, its interaction and the underlying mechanisms of the broadband photoluminescence, UV-VIS spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) system and photoluminescence spectroscopy (Pl) were used. © 2012 Elsevier B.V. All rights reserved.

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