Speaker
Mr
Bonginkosi Zikhali
(University of Zululand)
Description
The nuclear level density (NLD) and γ-ray strength function (γSF) are quantities that give
essential information about the behaviour of a nucleus at high excitation energy. NLD is defined
as the number of levels per unit of excitation energy. γSF is defined as a measure of the average
reduced γ decay probability of a nucleus. These concepts are useful at high excitation energies
where the spacing between the levels is small and gives information on degrees of freedom
and underlying nuclear dynamics. The evidence of the low-energy enhancement in the γSF for
energies less than 4 MeV has been discovered in several nuclei. Recently, a strong enhancement
of M1 transitions in 90Zr has been predicted for γ-ray energies below 2 MeV in shell model
calculations. In this work we explored the existence of the low-energy enhancement in the
neighbouring 91Zr isotope with the assumption that neigbouring isotopes have similar γSF and
hence provided first experimental NLD and γSF for this nucleus. The experiment 90Zr(d,p)91Zr
was conducted at the Oslo Cyclotron Laboratory (OCL). The SiRi (silicon telescope) array was
used to detect charged ejectiles from the reaction. The CACTUS (NaI(Tl) detectors) array
was utilized to detect γ rays that were in coincidence with charged particles. The nuclear
level density and γSF were extracted with the Oslo method. The existence of the LEE was
observed, which agrees with the shell model calculations in 90Zr. The NLD and γSF quantities
were used to calculate (n,γ) cross sections with the Talys reaction codes. These were compared
with experimental data from direct measurement to test the reliability of of the approach used in this work.
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
MSc
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
no
Primary author
Mr
Bonginkosi Zikhali
(University of Zululand)
Co-authors
Mr
Bonginkosi Kheswa
(iThemba LABS)
Dr
Mathis Wiedeking
(iThemba LABS)
Mr
Sifiso Senzo Ntshangase
(University of Cape Town / iThemba LABS)
