A Study on 19F(n,α) Reaction Cross Section
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- Uğur, F.A., Tel, E. & Gökçe, A.A. J Fusion Energ (2013) 32: 414. doi:10.1007/s10894-012-9587-4
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In this study, cross sections of neutron induced reactions have been investigated for fluorine target nucleus. The calculations have been made on the excitation functions of 19F (n,α), 19F(n,xα) reactions. Fluorine (F) and its molten salt compounds (LiF) can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure and also the molten salt compounds are also a good neutron moderator. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the full exciton model and the cascade exciton model. The equilibrium effects are calculated according to the Weisskopf–Ewing model. Also in the present work, reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14–15 MeV energy. The obtained results have been discussed and compared with the available experimental data.
KeywordsFluorine-19Alpha emission spectraCross-section
The development of fusion reactor technology requires the knowledge of cross sections of fast neutron induced reactions. Particularly, the neutron cross section data around 14–15 MeV energy have a critical importance on fusion reactor technology for the calculation of neutron spectrum, activation, nuclear heating in the components and radiation damage of metals and alloy [1–3]. The neutron induced reaction cross section data around 14–15 MeV energy are especially required to estimation of the radiation damage effects on structural fusion materials, because these reactions can cause a process resulting in the radiation damage in the structural materials because of gas formation in the structural fusion materials used in the construction of the first walls and core of the reactor. So, the radiation damage seriously influences the structural integrity of fusion reactor. Especially, due to the (n,α) reactions, the mechanical and physical properties of structural fusion material could be adversely affected with the generation of helium gas bubbles and voids and hence swelling of the structure. [4, 5].
Certain light nuclei such as Li, Be, F (FLİBE) and its molten salt compounds (LiF, BeF2 and NaF) can be used as breeding and coolant materials in fusion reactors due to its low melting point and vapour pressure. The molten salts can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure and also these compounds is also a good neutron moderator .
In this study, we have calculated the cross-section, by using Full Exciton Model (PCROSS), Equilibrium Model (PCROSS) and Cascade Exciton Model (CEM) reaction mechanisms for (n,α) reaction. And also alpha emission spectra were calculated by using the Full Exciton Model (PCROSS) and Equilibrium Model (PCROSS) for 19F nucleus.
In the calculations, pre-equilibrium alpha emission spectra were calculated by using full exciton model with PCROSS code . The obtained results have been discussed and compared with the available experimental data and found agreement with each other.
Calculations of Nuclear Reactions
Fast Neutrons Induced Empirical Cross Section Formulas
Tel et al. suggested using these new experimental data to reproduce a new empirical formula of the cross sections of the (n, p), (n, 2n), (n, α), reactions at 14–15 MeV neutron incident energy [12, 13].
Results and Discussions
Summary and Conclusions
The all model are higher than the experimental data for the 19F(n,α) reaction for incident neutron energy between 10 and 18 MeV.
When correction factor = 0.6 for Tel formula correspond to experimental data for the 19F(n,α) reaction for incident neutron energy between 10 and 18 MeV.
The all model calculations are very lower than the experimental data for the 19F(n,α) reaction for incident neutron energy 3–5 MeV.
The all model calculations are lower than the experimental data for the 19F(n,α) reaction in for incident neutron energy 2–10 MeV.
If the neutron with 14.1 MeV energy hits to 19F target nucleus, 19F target can emit alpha particle which has about 12–13 MeV kinetic energy
When the neutron with kinetic energy 14.1 MeV hits 19F, the experimental and theoretical cross-sections appear to give maximum value about emission alpha energy 3–5 MeV.