10 research outputs found
Model za elektrotvorbu kaona na protonima i lakim jezgrama
The Continuous Electron Beam Accelerator Facility (CEBAF) is by its high current and precision an excellent tool in studying hadronic structure. The experiment approved for 1996 aims at the separation of the longitudinal and transverse cross– sections and the K+ form–factor measurement in the reaction p(e, e’ K+)Λ/Σ. Kinematic conditions and trigger modelling have been computed for the two–arm spectrometer with a programme which optimizes the experimental conditions taking into account the expected cross–section and the spectrometer acceptance.Posebno prikladan uređaj za proučavanje hadronske strukture je Pogon akceleratora za neprekidan elektronski snop (CEBAF) u S.A.D. zbog njegove snažne struje i točnosti. Za 1996. je odobreno mjerenje kojim treba odrediti omjer uzdužnih i poprečnih udarnih presjeka i utvrditi faktor oblika K+ putem reakcije p(e, e’ K+)Λ/Σ. Izračunali smo kinematičke uvjete i okidne modele za par okretnih spektrometara, s programom koji optimizira eksperimentalne uvjete, uzimajući u obzir očekivane udarne presjeke i prihvatnost (akceptancije) spektrometra
Advanced Modelling of 238U(n,f) in a Fast Reactor Application
Fast neutron reactors, as a possible future solution on energy demand of human society, based on fission process of U, request new and reliable nuclear data necessary for new generation reactors design. Fission process induced by fast neutrons on U was investigated. Fission observables like cross sections and their uncertainties, fission fragment mass distribution, prompt neutrons emission, isomer ratios and other parameters were obtained by using Talys computer code or programs realized by authors. Then the production of isotopes like Xe, Mo, I, Y as well as yields of fissile nuclei were evaluated. Obtained theoretical evaluations are compared with existing experimental data
Astrophysical production of in nuclear p - processes
The large time of life of  suggests the possibility to use this p - nuclide as astrophysical chronometer to study the geochemical galactic evolution. Due to the high temperature and large densities of gamma quanta, neutrons and protons in stellar environment nucleus can be obtained in (γ,n), (n,2n), (p,2n) processes on .The knowledge of corresponding cross sections of gamma rays, neutrons and alpha induced processes is of a great importance for the explanation of ( /  ) ratio uncertainties observed on the Earth, meteorites, Moon and other celestial bodies.Cross sections of (γ,n), (n,2n), (α,γ) processes induced by fast gamma rays, neutrons and alphas on  and  from threshold up to 25 MeV were evaluated and predicted in the frame of Hauser-Feshbach statistical model by using Talys software and the own computer programs. For each nuclear reaction contribution of direct, compound and pre-equilibrium mechanisms were determined. Theoretical evaluations are compared with existing experimental data. Parameters of optical potential in the incident and emergent channels and of nuclear densities were extracted. Calculated cross sections together with corresponding nuclear data were used in the evaluation of astrophysical rates necessary in the determination of elemental abundances as needed by nuclear astrophysical networks