In the present research, the increase of nuclear spin effects on the fission barrier was studied for different nuclei. Then, the deposited energy in the target was calculated using MCNPX Code. Based on F7 tally, the released energies due to fission and the neutron production rate were measured for 238,240,242,244Pu, 242,244,246,248Cm and 252,254Cf isotopes. It was shown that by increasing the spin of nuclei from 4+ to 26+, the rate of neutron production for different isotopes also increases. The Simulation results showed that the increase in the energy of incident neutrons is proportional to the increase in the spin of the target nucleus. At last, the mutual effect of increasing spin on the nuclear deformation was investigated which indicates a good agreement with the Simulation results. One of the most important results of this work is that neutron collision with any energy increases the spin of nucleus. Finally, based on the comparison, it was found that the results of CNS (Cranked Nilsson-Strutinsky) Code are confirmed with that of MCNPX.

Neutron filter crystals are widely used in the nuclear industry, particularly in research reactors. One of the most important crystals used is sapphire crystal, which is grown in several countries to ensure good quality. This research aims to compare the neutron performance of sapphire crystals made in Iran with those of externally supplied crystals. An Am-Be source was used in this study to assess the ability of these sapphire crystals to remove fast neutrons. Additionally, a monochromatic neutron beam was used to study the impact of these crystals on reducing the intensity of the neutron flux. To verify the accuracy of computational Codes in simulating the neutron behavior of these filter crystals, the McStas Code was utilized. The results of this Simulation were then compared with available experimental data. Comparing the experimental results with those published worldwide revealed that the domestically grown crystals performed comparably to the foreign samples. The experimental findings showed that a 2.5 cm sapphire crystal filtered the monochromatic neutron beam with an energy of 0.06 eV by only about 5.5%, and fast neutrons with an energy of more than 200 keV by about 33%. Increasing the crystal thickness to approximately 6 cm increased the filtration of fast neutrons to about 60% and monochromatic neutrons to about 16.5%. Overall, the results of this study indicated that the discrepancies between the Simulation and experimental values may be attributed to the lack of detailed information necessary for crystal modeling in the computational Code.

Background: Making use of the orthovoltage machines in Radiotherapy, is one of the routine methods for the treatment of the superficial lesions. In this study, an important determinant of X‐ray quality, the HVL (Half Value Layer), has been evaluated. Materials and Methods: The HVLs of a orthovoltage X-ray machine in 120 and 180 kVp are measured, using an empirical method, in which the HVLs are derived from the absorption curves. The measured HVLs are compared with calculated (Monte Carlo Simulation) HVLs. Using the BEAMDP Code of Simulation, the output spectra are obtained and employed for the measurement of the HVLs.Results: Comparing the calculated and measured HVL values, the results show that the highest and lowest differences between the two are 4.96% and 2.27%, respectively, which are, in fairly good agreement with those obtained in the former studies.Conclusion: This study shows that the EGSnrc Simulation Code is capable of being used for the extraction of the quality indices for the superficial X‐ray radiotherapy machines. It seems that, the mentioned Code, with the mentioned experimental method, can be employed as a routine clinical test tool for every superficial radiotherapy department.

In the present work, we have simulated the collision of dust nanoparticles with graphite wall using LAMMPS Code, based on the molecular dynamics method. Dust particles have different shapes and sizes depending on their production mechanism in Tokamaks. In this work, two types of dust grains have been considered: a spherical tungsten nanoparticle and a graphite nanoparticle with an oblate geometry that collides with a graphite wall. In the fusion device, ions, hydrogen atoms, and molecules collide with the dust grain and create stochastic torques, leading to minor variations in the angular momentum of the grain. Therefore, in the Simulations, the dust rotation around its symmetry axis has also been considered in addition to the transfer velocity. For such nanoparticles, the threshold speed of nanoparticles that leads to surface damage has been estimated. The results show that, unlike tungsten nanoparticles, graphite grains do not play a significant role in the degradation of the graphite surfaces. Still, due to the speed of the collision, they may either stick to the surface or be damaged and return to the environment.

The accuracy of each simulating beta-voltaic battery parameter is very important, especially in microbatteries. The aim of this study is to improve the calculation of beta-battery parameters’ accuracy. For this purpose, at first, using the Monte Carlo N-Particle Code (MCNPX), the energy accumulation distribution of the 63Ni beta particle spectrum inside a silicon semiconductor has been simulated. Then, the ATLAS C-Interpreter function in C ++ was defined, using one of the SILVACO Code abilities (the parameter F. RADIATE BEAM statement). Finally, the device electric parameters have been obtained using ATLAS-SILVACO based on the location-dependent of MCNPX results. For validation, the calculations were performed for a battery sample made of 16 mm2 cross-section and 1 mCi activity of radioisotope 63Ni as a source, and finally, the results were compared with one experimental result and two analytical methods. The calculations repeated for the other sample with 100 mCi activity and 1 cm2 of geometry, and compared its results with an analytical method results. The results showed that the Simulation of micro-battery characteristics by the MCNPX-SILVACO hybrid Code using threedimensional electron-hole pairs’ distribution in semiconductor and the full spectrum of beta particles creates a significant increase in the accuracy of the computation, and provides a good capability to optimize the design of the battery.