Radiation Physics and Engineering
Volume:4 Issue: 1, Winter 2023

The domestic plasma modeling framework AZERAP is introduced and its capabilities in simulating the plasma based accelerators and intense beam-plasma interaction are discussed. The current first beta-release of AZERAP exploits the fully kinetic, electromagnetic relativistic PIC algorithm as its numerical engine. It is implemented in the object oriented language C++ and utilizes the Message Passing Interface (MPI) for parallelization. The main idea behind the development of AZERAP has been establishing a software platform for virtual plasma laboratory for plasma based particle beam sources and high power electromagnetic generators. Achieving this goal has implied attaining high functionality in introducing the input problem, supporting abstraction of the field and plasma structures/modules, and supporting high flexibility for future developments. The present first beta-release of AZERAP paws the way toward these objectives. Moreover, it offers a very comfortable user experience with code compile, debugging, execution, data accusation and data animation, simulating plasma based accelerators.

In this research, the effect of ions produced in deuterium plasma on Tungsten (W) and Aluminum (Al) plates has been investigated using a plasma focus device with the specifications of (C=10.4 μF, V=23 kV, E=2.75 kJ). The W samples used because it is one of the key elements in the Tokamak device. Because we wanted to put the W samples at the distance from the anode top with maximum plasma produced ions, we should find the optimum place. Due to the high cost of W samples, we used Al samples to find the optimal conditions. The samples were irradiated at 8 cm distance from the anode top with deuterium ions produced by a plasma focus device. The sample analyses were done by the SEM and EDX methods. The sample irradiation by deuterium plasma ions caused a lot of damages and bubble formation on the sample surfaces. The analyses showed the extent of surface damage and the number of ions deposited on the surface. The number of damages on the Al surface was much higher than W. Bubbles were formed on the surface were due to the impact of deuterium ions on the W and Al samples. Also, the deuterium ion energy was measured with a Faraday cup as about 50 keV.

In this paper, the spectrophotometric properties of a colored Nickel-based solution complex (Nickel nitrate hexahydrate and Methyl Orange (MO)) were investigated as a stable chemical dosimeter for using in radiation processing of agricultural products. Its simple synthesis method as well as low cost made it a suitable dosimeter for use in radiation processing. The variation of absorbed dose was applied to measure the absorbed dose. The maximum absorbance for the solution was observed at 460 nm. This solution was irradiated at three different concentrations of Ni(No3)2.6H2O and MO by Co-60 gamma-ray. Also the variation of the absorbance as a function of PH of the solution was investigated. The results showed the solution absorbance decreases with an increase in doses, and this solution can be used as a routine dosimeter and has a linear response in the 50 to 1500 Gy range with acceptable stability in environmental conditions up to 40 days before and after irradiation.

In the present paper, the dechanneling and the energy loss of protons at the energy interval of 1400 to 2200 keV along the {100} and the {110} planar directions of Si were studied by the simulation of the measured channeling Rutherford back-scattering spectra based on the exponential dechanneling function with a parameter λ. This parameter is proportional to the dechanneling rate and represents the mean distance that ions travel along the channel before escaping from the channel. The Levenberg-Marquardt algorithm was used to set the best values of the channeling to random energy loss ratio, and the mean channeling distance. The experimental results are well reproduced by this simulation. The data analyzed in this energy range did not show any particular trend with regard to energy dependence of the parameters. The differences between both the planar channels in the Si crystal and their influence on the energy loss ratio and dechanneling of proton ions are described.

We study the low-energy deuteron-deuteron elastic scattering using the cluster effective field theory formalism up to next-to-leading order (NLO). For this purpose, we initially focus on determination of the unknown effective field theory coupling constant values using the phase shift analysis and available differential cross section data. The differential cross section versus center of mass energy and scattering angle are plotted up to NLO in the suggested power counting and compared to the available experimental data. Our effective field theory results showgood consistency with the present data.

Actinide concentration and activity analysis of the nuclides resulted from the burnup (depletion) process during nuclear reactor operation lifetime is an essential problem in reactor design. Inventory and the corresponding activities of the Tehran Research Reactor (TRR) are evaluated using different methods and compared with each other. WIMS-CITATION, ORIGEN, and MCNP codes are used for plate type inventory calculations. The important actinides, fission products, and fissile inventory ratio of TRR have been calculated at different burnup steps. It is worth noting to mention that knowing the value of inventory helps us for safe handling of the spent fuels and to have a perfect design for transport cask of spent fuels. In this paper, the fuel isotope inventories were calculated for the first and 83rd core configuration of the Tehran Research Reactor, which is named “Core01” and “Core83” respectively. The calculations were first performed using WIMS-D5 and CITATION neutronic codes and then the results are compared with that of ORIGEN and MCNPX code. The total radioactivity of the TRR core at the end of the reactor core life (Core83) is estimated to be 6.47×105 Ci.

Probabilistic uncertainty and sensitivity analysis is frequently recommended for safety and reliability assessment of computer simulations. For this purpose, SUAP has been developed, and its latest version is capable of working on analysis results obtained using five well-known nuclear codes (i.e. FRAPCON, FRAPTRAN, FEMAXI, MCNP, and COBRA). SUAP provides support to properly quantify input uncertainties as to probability distributions and appropriate dependency functions. Using the Monte-Carlo sampling method, random combinations of different uncertain input parameters are generated and used to make input files for the corresponding code applied for the modeling. To quantify uncertainties, SUAP determines the variation range for each specific output parameter at any chosen time and/or location. Moreover, sensitivity analysis is accomplished based on the Spearman correlation. In this study, in order to evaluate SUAP applicability, UQ&SA for fuel performance modeling of VVER-1000 fuel rods using FRAPCON code has been accomplished. Acquired results exhibit the possible range of uncertainties in fuel centerline temperature, as well as the importance of different uncertain input parameters on that.

Nuclear radiations are harmful to the human body. The main sources of nuclear radiation are the decay chains of U-238, U-235, and Th-232 and also some radionuclides as K-40, which are present in small amounts in the materials of the earth's crust, including plants, rocks, soil and water. Radioactive substances are transferred to the human body in a variety of ways, including plant and animal products. Therefore, it is very important to determine the amount of radioactive substances in food products. In this research, seven samples of pistachios with different types were collected from Tehran markets in Iran. In this project, ultra-pure germanium spectroscopy system model GCD30195 was used. The specific activities of Ra-226, Th-232 and K-40 varied from ‎<1.96‎‎ to 9.86, from 1.21 to 1.95, and from 317.22 to 382.80 Bq.kg-1. The artificial radionuclide of Cs-137 in all samples was lower than minimum detectable value (MDA). Calculations of the radiological impact showed that consumption of pistachios would endanger human health. The results of this study also showed that the amount of natural radionuclides in pistachio cores is higher than pistachio shells.