Mahdieh Ghafouri; Hossein Sadeghi
Abstract
The mean-field model based on Skyrm Forces (SF) or associated density function has a wide application to describe nuclear states, collective vibrational excitation, and heavy-ion collisions. The Sky3D solves static or dynamic equations on a Cartesian 3-D mesh with isolated or periodic boundary conditions ...
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The mean-field model based on Skyrm Forces (SF) or associated density function has a wide application to describe nuclear states, collective vibrational excitation, and heavy-ion collisions. The Sky3D solves static or dynamic equations on a Cartesian 3-D mesh with isolated or periodic boundary conditions without further assumptions on the symmetry which shows more characteristics of the structure of nuclei. In the present work, time-dependent Hartree-Fock Skyrm (TDHF) calculations were completed on a set of Sn isotopes to obtain and compare the nuclear deformation parameters in static and dynamic states. It was found that in deficient neutron nuclei, even the most modern particle calculations unable to describe the improved collectivity below the mean shell in Sn approaching N= Z= 50. It was shown that the effective interaction plays an important role in the details of the reaction, and carries information about the heavy-ion reactions to the details of the effective interaction.
Behnaz Kaleji; Mohammad Mahdavi
Abstract
The inverse bremsstrahlung absorption is one of the most absorption processes in inertial confinement fusion plasma. In the present work, some important optical properties of plasma, such as index of refraction, absorption coefficient, electrical conductivity, and the electrical dielectric function in ...
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The inverse bremsstrahlung absorption is one of the most absorption processes in inertial confinement fusion plasma. In the present work, some important optical properties of plasma, such as index of refraction, absorption coefficient, electrical conductivity, and the electrical dielectric function in degenerate conditions are presented from an average atom model's point of view. To include quantum diffraction effects, the Coulomb potential is replaced by an effective quantum potential for a screened electron-ion interaction, named Klebg potential. Therefore, the electrical conductivity contribution of the free-free electrons absorption that is inverse of the bremsstrahlung absorption, for transition from state i to state j is obtained using the wave function of this potential. By this method, the effect of degenerate plasma on the inverse bremsstrahlung power is calculated using the free-free absorption coefficient. Finally, the obtained results of the free-free optical opacity of plasma and the inverse bremsstrahlung absorption power from classical and degenerate plasma are compared.
Sajjad Shahmaleki; Faezeh Rahmani
Abstract
In this research, the Tm content as codopant in CsI(Tl) was optimized for reducing the afterglow. As an experimental reference, CsI(Tl) and CsI(Tl-0.05%Eu) single crystals were grown by Bridgman method. The grown crystals were characterized through photoluminescence analysis, and the measurements of ...
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In this research, the Tm content as codopant in CsI(Tl) was optimized for reducing the afterglow. As an experimental reference, CsI(Tl) and CsI(Tl-0.05%Eu) single crystals were grown by Bridgman method. The grown crystals were characterized through photoluminescence analysis, and the measurements of charge collection time, energy resolution, photon light yield as well as the amount of afterglow were performed. It was observed that the change in codopant shifted the emission curve of Tl+. For CsI(Tl) codoped with Tm in the range of 0.02 to 0.1 mol%, the afterglow of 0.05 mol% Tm reduced in comparison with Tm-free CsI(Tl). The results showed that the Tm codopant resulted in a decrease of 32 to 42% in afterglow depending on the Tl concentration. The addition of various contents of Tm also decreased the light yield, up to 23%, and as well as the resolution about 2 to 33%. The light yield exhibited insignificant changes, whilst the measured energy resolution was about 8.8% at 662 keV. Overall, the improvement in the afterglow, as well as the insignificant reduction in both the energy resolution and light yield of CsI(Tl-Tm), may motivate some researchers to consider it as a good candidate for fast spectroscopy and high-frequency imaging applications.
Saeed Kakaei; Elham Sattarzadeh Khameneh; Akbar Monji Boveiri
Abstract
For the first time, sorption characteristics and mechanisms of group-4 elements were investigated and compared in extremely acidic solutions (4 M HCl) by rice bran (RB) biomass. Numerous instrumental strategies and hard-soft acid-base (HSAB) theory were applied to investigate the sorption features and ...
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For the first time, sorption characteristics and mechanisms of group-4 elements were investigated and compared in extremely acidic solutions (4 M HCl) by rice bran (RB) biomass. Numerous instrumental strategies and hard-soft acid-base (HSAB) theory were applied to investigate the sorption features and mechanisms of Ti(IV), Zr(IV), and Hf(IV). The specific surface area of the raw biomass was 4.79 m2.g−1 as determined by Barrett-Emmet-Taller analyzer (BET). Deposition of planned metal ions on the biomass was determined through a scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDS). The linkage of C=O, O-H, and N-H functional groups of biomass with metal ions became clear with Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrum analysis. The role of C=O functional group of ammonium oxalate/ammonium carbonate in metal ions desorption was confirmed by elution experiment. The experiments showed that the high-affinity of rubidium to sorption of zirconium and hafnium (>99%) was owing to their lower hydrated ionic radius. From all the results obtained, exhausting-hard interactions and electrostatic complexation mechanism were diagnosed between hard-functional groups of RB biomass and hard cations of Ti(IV), Zr(IV), and Hf(IV).
S. Farhad Masoudi; Fatemeh Sadat Rasouli
Abstract
Due to the selectively treating tumors and largely sparing normal neighboring cells, Boron Neutron Capture Therapy (BNCT) continues to be of special significance and interest for wide groups of researchers. One of the most important challenges in this context is to design an optimized ...
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Due to the selectively treating tumors and largely sparing normal neighboring cells, Boron Neutron Capture Therapy (BNCT) continues to be of special significance and interest for wide groups of researchers. One of the most important challenges in this context is to design an optimized beam based on an appropriate neutron source. The recent studies, focused on investigating neutron sources as alternatives for nuclear reactors, revealed the high potential of electron linac-based photoneutron sources to improve the efficiency of this treatment method. Inquiring about the efficiency of a layered model of beam shaping assembly (BSA) for photoneutron sources to be used in BNCT of deep tumors is the main subject of this simulation study. This model, unlike the traditional BSA in which the reflector surrounds the whole moderator, includes many concentric cylinders of reflectors and moderators. The MCNPX simulations for various primary energies show that the layered model results in more appropriate beam characteristics compared with that of the common geometry. Moreover, the parameters governing the beam properties such as the thickness of the layers, moderator/reflector and collimator lengths, and the thickness of the surrounding reflector have been investigated. The results are encouraging and offer new ways to accomplish more researches in studies on the BNCT technique.
Javad Karimi; Mohsen Shayesteh; Mehdi Zangian
Abstract
Today, small modular reactors have received considerable attention in various countries. The ABV reactor is a PWR small modular reactor that has various applications. This reactor has been used silumin metal fuel with a 16.5% enrichment. In the present work, the efficiency of the conventional UO2 fuel ...
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Today, small modular reactors have received considerable attention in various countries. The ABV reactor is a PWR small modular reactor that has various applications. This reactor has been used silumin metal fuel with a 16.5% enrichment. In the present work, the efficiency of the conventional UO2 fuel with enrichment of less than 10% to be used as the main fuel of ABV reactor has been investigated, and four different patterns for the reactor core have been proposed. To perform the calculations, the ABV reactor is modeled using the PARCS neutronic code and the RELAP5 thermohydraulic code. Finally, using computational codes for the proposed patterns of the reactor core, various quantities including reactor cycle length, reactivity, burnup, power distribution, fuel, coolant temperature distribution, and feedback coefficients have been calculated.
