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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:33 |
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Conference: Bucharest University Faculty of Physics 2014 Meeting
Section: Nuclear and Elementary Particles Physics
Title:
Even-odd effects in prompt neutron and gamma ray emission of even-even fissioning nuclei
Authors:
Georgiana GIUBEGA(1), Iuliana VISAN(1), Anabella TUDORA(1), Franz-Josef HAMBSCH(2)
Affiliation:
1) University of Bucharest, Faculty of Physics, Magurele, Romania
2) EC-JRC Institute for reference Materials and Measurements, Geel, Belgium
E-mail
giubega_georgiana@yahoo.com
Keywords:
even-odd effect; prompt emission in fission; prompt fission neutron multiplicity
Abstract:
Compared to proton even-odd effects in fission fragment distributions- that were extensively studied- the even-odd effects in prompt emission received less attention. In this context the present work is focusing on the even-odd effects (in both Z and N) appearing in prompt neutron and gamma ray emission. The even-odd effects in prompt emission were studied for four even-even fissioning systems: 233,235U(nth,f), 239Pu(nth,f) and 252Cf(SF). The results of this study show that the even-odd effects are mainly due to the Z even-odd effects in fragment distributions and charge deviations and N even-odd effects in average neutron separation energies. The average prompt neutron multiplicity as a function of Z, í(Z), exhibits the most pronounced even-odd effect, its global size decreasing with increasing fissility. The N even-odd effect in average neutron separation energy often influences the global even-odd effects in prompt neutron multiplicity in an opposite sense compared to the Z even-odd effect. The average prompt neutron multiplicity as a function of TKE shows an increase of the Z even-odd effect with increasing TKE and this effect is decreasing for heavier fissioning systems. The Z even-odd effects in the average prompt ã-ray energy and the average prompt neutron energy have comparable sizes and are lower than the even-odd effects in prompt neutron multiplicity.
Different average prompt emission quantities (as a function of A, of Z, of TKE and total averaged ones)- depending on fragment distributions- are affected by the even-odd effects in Y(A,Z,TKE). The primary multi-parametric matrices of prompt emission quantities- which are not depending on Y(A,Z,TKE)- are affected by the N even-odd effect in neutron separation energy and by the Z even-odd effect in the charge deviation.
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