Abstract In this study, the ion exchange process of cerium and yttrium using Dowex 50W-X8 resin was investigated and the behavior of the breakthrough curves were reported. The ion exchange percentage for Ce(III) and Y(III) was 73.93% and 70%, respectively. Mathematical modeling was performed to calculate the mass transfer components. Various mass transfer resistance mechanisms such as film diffusion resistance, intraparticle diffusion and axial dispersion as well as other mass transfer approximations were investigated by the linear driving force (LDF) model. Investigations showed that intraparticle diffusion resistance had the largest contribution in the ion exchange process of rare elements cerium and yttrium (R_f<R_ax<R_int). Intraparticle diffusion, i.e. the second stage of the overall ion exchange mechanism, was identified as the controlling stage of the process. Also, the Biot number for Ce(III) and Y(III) was greater than 30, indicating that the rate-controlling step of the ion exchange process was intraparticle diffusion. Thus, the accuracy of the studies was confirmed. The Peclet number also matched the slope of the breakthrough curves well.

Abstract Iodine-123 radionuclide was produced through the bombardment of a xenon-124 gas target using protons with energy of 28.5 MeV in a cyclotron accelerator. After confirming the quality control procedures, the iodine-123 radionuclide with a purity of more than 99% and activity concentration of 8.47 ± 0.2 GBq/mL was used for labeling of MIBG chemical compound. The quality control of the labeled compound was performed using thin layer chromatography method by acetic acid:water:butanol (1:1:4) as the mobile phase. The quality control results indicated a radiochemical purity of more than 99% for the final product. The biodistribution of the radiolabeled compound was evaluated following the injection of 5.5–11.1 MBq of the 123I-MIBG radiopharmaceutical into rats, and the rats were dissected at various time intervals and imaging was performed. A comparative analysis of the biodistribution of free 123I and 123I-MIBG revealed that the radiolabeled compound exhibited a distinctly different biodistribution pattern compared to free 123I.

Abstract In this study, the accurate diagnosis and differentiation of healthy and cancerous brain tissues was investigated using laser fluorescence imaging guided by the sodium fluorescein exogenous fluorophore and the results are compared with tissues auto-fluorescence images. Samples, which were diagnosed as meningioma, metastatic carcinoma, low-grade glioma, as well as high-grade glioma types by pathologists, were obtained from 4 patients and optical imaging technique with hematoxylin-eosin staining is used to validate the results. The findings reveal that the intensity of fluorescence radiation from cancerous tissues is more intense than that from healthy tissues due to the greater permeability of the dye in the cavities and pores of the tissue. In addition to increasing the accuracy and precision of the results, this imaging method allows the surgeon to visualize and diagnose the tumor in real-time and completely resect the tumor, eliminating the need for invasive biopsies. Therefore, the results indicate that sodium fluorescein can be used as a reliable fluorescence marker in intraoperative imaging to improve the diagnosis and delineation of brain tumors.

Abstract An anodic electrophoretic method has been used to create a uniform thin film coating on thin steel plates. The changes in the contact angle of the plates have been carefully measured. Then the samples were tested in a boiling pool to measure the critical heat flux and the boiling heat transfer coefficient. For the numerical simulation of plates with different wettability, after validation, by changing some of the boiling parameters to parameters that depend on the contact angle, the critical heat flux has been calculated for variable contact angles. The experimental results and numerical simulation are close to each other and show a similar trend. These results are also compared with other experimental data and their difference is less than 5%.

Abstract Nickel-based alloys were highly regarded due to their strength and good corrosion resistance at high temperatures. From the group of nickel-based superalloys, the Ni-12.5Mo-7.8Cr alloy has attracted the attention of researchers more than other structural materials due to its low production cost, easy access, excellent weldability, and excellent resistance to hot corrosion. In this research, the microstructural changes caused by hot rolling on the mechanical properties and fracture behavior of Ni-12.5Mo-7.8Cr nickel base superalloy were studied and investigated. For this purpose, hot rolling operation at 1100 °C was performed on the homogenized ingot at 1177 °C for 20 minutes. Microstructural investigations, fracture behavior and mechanical properties were carried out using optical and electron imaging analyzes and tensile tests. Microstructural investigations showed the formation of coarse and fine grains and creation of inhomogeneous structure after the hot rolling process. Also, according to the tensile test results, hot rolling led to an improvement of approximately 120% yield strength and a decrease of approximately 13% in the final tensile strength. Also, the fracture pattern of the homogenized and rolled sample shows the change of the fracture mechanism from soft to grain boundary brittle as a result of hot rolling.

Abstract Positron Emission Tomography (PET) is an advanced tool for the diagnosis and staging of cancer, based on the detection of glycolytic activity in malignant cells. This method requires drugs such as Fluorine Deoxy Glucose (FDG), the production of which necessitates the separation of Fluorine-18 and Oxygen-18 isotopes with a purity exceeding 95%. The use of cryogenic distillation columns as a suitable method for producing enriched oxygen is significant, despite the associated challenges of cost and efficiency. This study investigates the optimization of distillation column performance, analyzing the effects of factors such as input temperature and pipe height using MATLAB software. The results indicate that the maximum separation of the desired isotope depends on the type of isotope and the conditions of the apparatus, while the type of feed has no effect on concentration distribution. These findings can contribute to the development of optimization methods for the production of isotopes needed in medical imaging.

Abstract The radioactive radon gas infiltrates enclosed spaces through building materials and soil, and its accumulation in buildings with inadequate ventilation can pose health risks to residents. This study simulates and analyzes the impact of ventilation rates and building interior geometry on airflow patterns and radon distribution in an apartment unit using Computational Fluid Dynamics (CFD). The simulation results showed that the behavior of airflow and radon accumulation under various ventilation rates cannot be precisely predicted. Despite a reduction in average radon concentration due to increased ventilation rates, localized radon buildup occurs in certain areas due to vortex flows, with concentrations in these spots reaching multiple times the average concentration. These findings highlight the limitations of natural ventilation in creating a stable and uniform flow pattern for the complete removal of radon from all areas within the interior space. Additionally, a comparison of simulation data with experimental measurements showed a good match, confirming the accuracy of the CFD model. The findings of this study indicate that to effectively reduce radon concentration in enclosed spaces, precise ventilation system design that considers airflow patterns and the complexities of spatial geometry is essential.

Abstract One of the main problems in proton computed tomography is the reduction of the spatial resolution of the image due to the multiple coulomb scattering of protons while passing through the material. To deal with this problem, it is necessary to model the most likely path of protons (MLP). In this regard, artificial neural networks, as one of the innovative solutions in the field of machine learning, have helped to improve the accuracy of estimating the most likely path of protons. In this study, an artificial neural network with adaptive moment estimation optimization algorithm was designed to estimate the most likely proton path (MLP). The training of the network was done using the data obtained from the simulation of the proton computed tomography system in Geant4, so that 60% of this data was allocated for training, 20% of the data for validation, and 20% for the model test. These data contained information such as the position of entry and exit of protons, energy deposit, exit angle of protons and 10 points forming the path for each proton. The image matrix was modified with the help of the most likely path estimated by the neural network (MLP) and the cubic spline path (CSP), and the image was reconstructed using the Filtered Back Projection algorithm. The results of this study showed that the MLP method was able to achieve a spatial resolution of 5 line pairs/cm, while this value was equal to 3 line pairs/cm for the CSP method.

Abstract The Target Normal Sheath Acceleration (TNSA) method is one of the most efficient techniques for laser ion acceleration. One of the main challenges in optimizing this method is the detrimental impact of laser pre-pulses on the target, which can lead to plasma formation and changes in material density and temperature, resulting in shock wave formation and reduced acceleration efficiency. This study investigates the effects of laser pre-pulse duration and intensity (ASE) and target material on the formation and propagation of shock waves in the proton acceleration process via the TNSA method. The numerical results and one-dimensional hydrodynamic simulations indicate that, at lower ASE intensities (around 1011 W/cm2 and durations of 1 to 2 nanoseconds), the aluminum foil target undergoes minimal displacement, and due to the lack of deformation at the target’s rear side, It is expected that due to the lack of deformation at the target’s rear side, ion acceleration performance will not degrade. However, as the pre-pulse intensity increases, especially in lighter materials such as CH polymer, density variations and target displacement become more pronounced, which reduces the acceleration efficiency. These findings provide a basis for determining optimal conditions for laser acceleration experiments.

Abstract In this article, the structure and performance of the designed and constructed laser facility to perform basic research on the field of inertial confinement fusion and laser-plasma interaction have been studied. The laser facility has four laser beams and the optical amplifiers are based on the phosphate Nd:Glass solid-state active medium. The vacuum spatial filters have improved the beam quality and reduced the misalignment sensitivity of the optical structure. More than 30 Joules per beam have been achieved, and the total optical energy of the laser facility exceeds 120 J. The laser facility is upgraded to increase laser optical energy to 500 J. Temporal pulse-shaping of the laser master oscillator, the optical self-alignment systems, and equalization of the propagation time of laser beams from the laser source to the target position based on the heterodyne interferometer, are the main activities to make the implosion experiments of the pellets filled with the heavy isotopes of hydrogen for studying the inertial confinement fusion.

Abstract In this paper, the injection of Nitrogen electrons due to ionization in a laser-plasma accelerator is studied. For this purpose, the propagation of short and intense laser pulses with different pulse shapes in a combination of Hydrogen atoms (low atomic number) and Nitrogen atoms (high atomic number) is considered. Using the single-particle Hamiltonian in the plasma wave field caused by the ionization of Hydrogen atoms, the physics and the mechanism of electron ionization injection in the appropriate phase are investigated. Then, the results of the particle-in-cell (PIC) simulation code show that the population and maximum energy of the trapped and injected nitrogen electrons due to ionization are strongly dependent on the laser pulse shape.

Abstract This research presents an innovative surveillance system capable of real-time detection, identification, and localization of radioactive materials within video feeds from surveillance cameras. By combining advanced image processing algorithms and gamma-ray spectroscopy, this system offers a novel approach to the challenge of radioactive material detection. Image processing techniques are employed to identify and track objects, such as bags or packages, that may contain radioactive materials. Simultaneously, gamma-ray spectrometers measure the energy spectra emitted by radioactive sources, enabling the identification of radionuclides through spectral analysis. Data fusion techniques integrate the information derived from image processing and spectroscopy, yielding accurate and reliable localization and identification of radioactive materials. Experimental results demonstrate that detector placement and distance from the radioactive source significantly influence the system's performance. In a recent experiment, the system identified and localized a contaminated radioactive source containing Cs-137 (100 ci) within 20 seconds and 5 seconds, respectively. This approach offers a cost-effective and efficient solution for radioactive material detection and localization, surpassing conventional methods. With broad applications in world security, nuclear facility monitoring, and environmental surveillance, this innovative system empowers timely and informed decision-making in the face of nuclear threats and incidents, enhancing preparedness and response capabilities.

Abstract In this research, the absorption of uranium from sulfate solution containing uranium by strong basic anionic resin Amberlite IRA-402 has been investigated. the purpose of this study is to investigate the effect of pH parameters, the amount of adsorbent used, the initial concentration of uranium metal ions and contact time on the amount of uranium absorption from the solution obtained from the leaching of the ore in the batch system. The results obtained for uranium absorption showed that at pH 3, the amount of adsorbent used is 2g/l and the equilibrium time is 100 minutes, the maximum amount of absorption occurs. In the study of the effect of concentration on uranium absorption, it was observed that with the increase of the initial concentration of metal ions, the absorption percentage decreases, but the absorption rate per gram unit of the adsorbent increases. The results of kinetic experiments in optimal conditions for uranium absorption and matching the experimental data with the first-order and second-order kinetic models showed that the process of uranium absorption by Amberlite IRA-402 resin follows the pseudo-second-order kinetic model.

Abstract In this work, display screen samples of five mobile phone models including Huawei-y7, Nokia6, Iphone5, Sony-c3 and Shiaomi-note were investigated in order to use for accident dosimetry. After separation and washing with HF acid and ethanol, pieces with dimensions smaller than 5 mm × 5 mm from each sample were prepared. The samples were irradiated with 60Co gamma rays of Theratron 780 irradiator with a few absorbed doses between 0.01 and 10 Gy. Thermoluminescence (TL) signal of each sample normalized to its mass was measured with a Harshaw 4500 reader from 50 to 300 oC with a rate of 5 oC s-1. Calibration curves obtained for the samples showed that for all models the signal intensity linearly increases with the dose. On the other hand, significant light and time fading were observed for the TL signals measured for all models. Therefore, it is necessary to investigate the samples in darkness as soon as possible after the accident. Overall, Iphone5 possessing the most signal intensity per unit absorbed dose and the least minimum measurable dose (MMD) value recognized as the most appropriate model for accident dosimetry between the models investigated.

Abstract In this research, a drop accident for a fuel assembly in Tehran research reactor on other fuel assembles inside the reactor core is analyzed mechanically during fuel shuffling or loading. The purpose of the analysis is to ensure the structural integrity of fuel assembly during this incident. In this simulation, the ABAQUS software is applied for collision analysis. Three modes are considered for a fuel assembly and its collision with another assembly inside the core. It includes the vertical and symmetrical impact of an assembly on top of another assembly; the second, vertical and asymmetric impact of an assembly on top of another assembly; and the third, vertical impact of an assembly of one assembly to the fuel side plate of another assembly in the reactor core. The stress analysis showed that in the first and second cases, the falling fuel assembly first hits the Handling Pin in the upper part of the target fuel assembly, and with its resilience, the fuel plate is protected against external impact force. But in the third case, the fuel side plates are damaged and there is a possibility of losing its integrity.

Abstract In this paper, energy levels of the high-spin states of nuclei has been studied. To retrieving energy levels, the levels were first labeled based on the SU(3) dynamical limit of the interaction boson model and then the results were calculated in both the three-level and two-level interaction boson models. It can be seen that the developed three-level interaction boson model has a great advantage over the two-level model, and the spectrum obtained for energy levels using this model is in good agreement with the experimental spectrum, which shows that this model in the description and recovering energy levels with high spin state is more successful. This model also works better in describing levels of high spin states than . Examining the results of energy level calculations, it was observed that the developed three-level interaction boson model in retrieving the levels of nucleus is better than , because nucleus shows a higher degree of deformation than due to its deformation parameter value.

Abstract The combination of Compton imaging and positron emission tomography, which is also known as the combined Compton-positron emission tomography (Compton-PET) imaging system, has received attention due to the improvement of spatial resolution and imaging sensitivity compared to PET imaging alone. Compton-PET simulated system consists of two concentric detector rings. The inner ring with a smaller diameter is called the Compton scattering detector, the scatterer, and the outer ring, which has the dual use of Compton scattering detection and PET detector, is called the absorber. Considering the importance and many applications of PET imaging, the purpose of this research is to use the Compton-PET imaging approach and simulate this system with the 4GEANT tool, to achieve a better image output by increasing the spatial resolution. In this simulation, the geometry of two detector rings consisting of cubic crystals for the absorbing detector and the scattering detector inside the universe was considered. The gamma radiation source of the type that emits gamma with energy 511 keV was placed in the Micro-Derenzo phantom. In this research, image reconstruction is done using the MLEM iteration algorithm with 20 iterations. According to the obtained results, the value of FWHM is reported as 2.8 mm. For validation, the results were directly compared to the NEMA NU 2-2007 standard, which is provided for the measurement and reporting of positron emission tomography (PET) performance parameters.

Abstract Substitution of hydrogen with deuterium as a heavier and stable isotope in different molecules leads to interesting and significant effects in various industries like electronics and medicine. One of the important applications of heavy water is the usage of it in hydrogen–deuterium exchange reactions for the production of organic compounds having deuterium atom. Deuterated nitrobenzene is a valuable raw material for the production of deuterated aniline used in organic light-emitting diode industries. The aim of this study is to consider the required conditions for the synthesis of nitrobenzene-d5 with 99.5% atom D. Our studies indicated that preparation of nitrobenzene-d5 from hydrogen–deuterium exchange is not an appropriate method. In this article, under the condition of nitration with sulfuric acid and nitric acid as a source of nitronium, nitrobenzene-d5 was synthesized from benzene-d6 produced from the reaction of benzene with heavy water. Reaction temperature and concentration of sulfuric acid and nitric acid were optimized in order to avoid by-product formation and also to prevent reduction in isotopic enrichment during the conversion of benzene-d6 to nitrobenzene-d5. The product was characterized and analyzed by FT-IR, 1HNMR, mass spectroscopy, and gas chromatography.

Abstract Microwave interferometers are among the most important diagnostic tools in measuring the electron density of tokamak plasma. However, single-channel interferometers only measure the linear average of the plasma density along the central chord of the tokamak cross-section and do not provide accurate information on the spatial distribution of the density. Multi-channel microwave interferometers allow for the measurement of the radial profile and spatial distribution of the tokamak plasma density. This information is essential for studying magnetic instabilities, optimizing energy transfer, and controlling the plasma. Currently, the interferometer in the Alvand tokamak is single-channel and only measures the linear average of the plasma density along the central chord. This limitation reduces the accuracy and comprehensiveness of the plasma data. The main objective of this paper is to design a multichannel interferometer system for the Alvand tokamak that can measure the radial profile and spatial distribution of electron density. This system is designed based on five symmetrical channels for transmitting and receiving microwave beams along the main radius and sub-chords of the Alvand tokamak to provide more comprehensive information on the spatial structure of the plasma. For efficient beam transmission with less loss, the use of tapered waveguides with larger dimensions was proposed. The requirements of spatial constraints for installing wave transmitting and receiving equipment around the vacuum chamber, measurement and calibration requirements of the proposed multi-channel interferometer were also examined. The proposed design will provide a significant improvement towards completing the active remote diagnostic systems of the Alvand Tokamak.

Abstract One of the important methods for studying the structure of the nucleus is the thermodynamic description of the nucleus. Although the nucleus consists of a fermionic system with a few particles, it experiences thermal fluctuations in particle number. In this task, thermodynamic quantities such as the excitation energy, level density parameter, and nuclear level density have been calculated by taking into account temperature-dependent pairing correlation as well as the statistical and quantum fluctuations using the LN model. Furthermore, by putting the calculated level density parameter from the LN model into the level density relation derived from the BSFG model, the nuclear level density has been obtained using this approach. Finally, the computed level densities using the mentioned models have been compared with each other and with the experimental level density.

Abstract In this research, the recovery of uranium from refractory ores in the northern region of Isfahan by acid washing and acid leaching processes has been studied. Also, the effect of different parameters on acid washing and acid leaching was investigated. The results showed that acid concentration and liquid-to-solid ratio in acid washing as effective factors uof acid washing, as well as leaching temperature, leaching time, amount of acid and liquid-to-solid ratio are important factors in uranium recovery from refractory ores. The optimal parameters of the process include acid concentration of 0.5 M and liquid to solid ratio of 4.5 in the acid washing process, as well as temperature of 20 degrees Celsius, time of 5.5 hours, acid amount of 300 kg per ton of ore and ratio 2.5 liquid to solid was obtained in the sales process. Under these conditions, the efficiency of uranium extraction from refractory ores in the northern region of Isfahan was 83%.

Abstract This study focuses on evaluating and optimizing the arrangement of photomultiplier tubes (PMTs) in a plate plastic scintillator detector for applications in position-sensitive detection of radioactive sources. To achieve this, scintillation light processes within the detector were modeled and analyzed using Monte Carlo simulations implemented in the Geant4 toolkit. The research examines three distinct PMT configurations: a central configuration (PMTs placed at the center of each side of the detector), an asymmetric configuration (PMTs arranged unevenly with varying distances across the detector surface), and a corner configuration (PMTs positioned at the corners of the detector). Statistical analysis of the results indicates that the central configuration yields the best performance, with minimal errors: RMSE = 1.51 cm, MAE = 1.26 cm, MRE = 7.03%, and a correlation coefficient R = 0.997. In comparison, the second and third configurations demonstrate reduced accuracy in source localization. These findings suggest that an optimized PMT configuration can significantly enhance the precision and efficiency of detection systems, making them particularly effective for spatially sensitive applications in identifying and localizing radioactive sources.

Abstract Prostate-Specific Membrane Antigen (PSMA) is a membrane-bound glycoprotein that is overexpressed in prostate cancer. PSMA has been recognized as a promising target in the diagnosis and treatment of prostate cancer. Alpha particle-emitting radionuclides have shown promising results as radiotherapeutic agents for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Actinium-225 (225Ac), with T½ = 9.9 d, has been one of the most commonly used options for clinical applications. 225Ac emits five alpha particles with energy ranges from 5.8 to 8.4 MeV during its decay chain. The decay cascade also includes beta particle emissions ranging from 0.6 to 2 MeV and gamma emissions from Francium-221 (221Fr) and Bismuth-213 (213Bi). Considering the favorable properties of this radionuclide for targeted alpha therapy of prostate cancer, this study initially determined the radionuclide purity of 225Ac using gamma spectrometry equipped with a high-resolution high-purity germanium detector and a liquid scintillation detector. Then, PSMA-617 labeling was performed with 225Ac at 95°C for 30 minutes. The radiochemical purity of the resulting compound was determined to be over %96 using thin-layer chromatography. This study demonstrated the successful labeling of PSMA-617 with 225Ac under optimal conditions and high radiochemical purity for clinical applications.

Abstract Among alpha-emitting radioactive nuclei for clinical applications, Actinium-225 (²²⁵Ac), with a half-life of 9.9 days, is widely used. This radionuclide undergoes a decay chain, emitting five alpha particles in the energy range of 5.8 to 8.4 MeV. The decay cascade also includes beta emissions from 0.6 to 2 MeV and gamma radiation from Francium-221 (²²¹Fr) and Bismuth-213 (²¹³Bi). This study aimed to calculate S-values, the absorbed dose per decay from the source organ to the target organ in mSv/MBq.s, for ²²⁵Ac and its daughters in the adult male ORNL phantom (225 source-target organ pairs) using the MCNPX2.7 code. The accuracy of the code was verified by computing the specific absorbed fraction (SAF) and comparing it with ORNL data. The results of MCNP and ORNL data showed strong agreement when the source-target organ distance and size were appropriate. However, in cases with greater distances or complex geometries, discrepancies were observed, attributed to the different computational methods used by ORNL in these situations. This study confirmed that ²²⁵Ac and its daughters, especially Polonium-213 (²¹³Po), deliver a high dose to target organs. The MCNPX simulation showed good accuracy compared to ORNL data and can aid in optimizing targeted alpha therapy.

Abstract In this study, magnetic pulse welding (MPW) is proposed as a solid-state welding solution for the metallurgical joining of dissimilar aluminum-copper metals. The coil type used in MPW is a critical factor influencing joint quality, depending on its geometry and electromagnetic performance. Two types of flat coil, a double-sided H-shaped coil and a single-sided E-shaped coil, were used for welding dissimilar aluminum-copper metals. Welding was performed at a discharge voltage of 16 kV, a capacitor bank of 120 μF, and an air gap of 0.7 mm. After 10 welding repetitions, the coils’ morphology was evaluated. The joint interface was analyzed using field emission scanning electron microscopy (FE-SEM). Examination of the coils showed that the double-sided inductor underwent plastic deformation after 10 welds due to magnetic field interference. This deformation increased the coil-workpiece gap, reducing process repeatability.The results of the electron microscope examination of the joint interface showed the formation of a transition zone, a wavy morphology, waves, and separated copper pieces at the joint interface. The formation of the transition zone occurred only in welding with a double-sided coil, which indicates a much higher impact intensity in the type of coil compared to the single-sided coil. Also, the width of the joint interface in welding using a single-sided coil has decreased from 3.5 μm to 0.6 μm compared to the double-sided coil.

Abstract Recently, special attention has been paid to the use of nanoparticles (NPs) in radiation therapy to enhance the therapeutic gain. Combining proton therapy with Magnetic Resonance Imaging has been developing rapidly. One of the associated challenges is the possible impact of a magnetic field on the dose distribution around NPs. In the present study, the dose enhancement factor of a 25 nm radius gold, gadolinium, and superparamagnetic iron oxide NP irradiated by protons of 50, 150, and 250 MeV has been examined with and without the presence of a static magnetic field with different strengths. In addition, two simulation approaches (single-stage and phase-space approaches) using the Geant4 toolkit are considered and the results from two electromagnetic physical lists, Livermore and Penelope, are compared. The results show that using heavier NPs (i.e., high density and effective atomic number) increases the dose more than the lighter ones. The difference between the two investigated physics lists is significant in the low-energy region and reaches up to 20% in dose enhancement factor calculations. Moreover, a magnetic field with a strength of up to 7 T did not reveal a significant effect on the dose distribution around NPs and the number of secondary particles. The results of this study have paved the way for experimental studies of the feasibility of combining proton therapy with the simultaneous presence of NPs and magnetic field, which can be helpful before the start of the clinical phase.

Abstract Abstract: The aim of this study is to analyze and compare the spectral and spatial characteristics of plastic rod and plate detectors. In this context, the variations in the FWHM at the Compton edge of the energy spectrum at different source positions for both types of detectors were investigated. For this purpose, the energy spectra of the detectors were recorded at various source positions and analyzed separately. The dimensions of the rod detector were 5 × 50 cm, and the dimensions of the plate detector were 50 × 5 × 50 cm. The results show that as the distance between the source and the detector increases, the FWHM increases in both types of detectors; however, the change is more pronounced in the rod detector compared to the plate one. These differences are attributed to the geometric characteristics and photon scattering behavior in each detector. Furthermore, the results indicate that the rod detector have higher spatial resolution. These features could be useful in optimizing the geometric design of detectors for applications such as nuclear imaging, industrial tomography, and others.

Abstract In centrifuge machines, the study of gas dynamics is of critical importance not only within the rotor but also in the surrounding external region. To reduce both pressure and frictional power losses in the space around the rotor, molecular pumps are employed. Given the direct interaction between the pressure in the top-end region and that within the rotor, understanding their mutual influence is essential for optimal machine design. Predicting the wall pressure of the rotor during the gas feed process, along with defining acceptable ranges for variations in operational and geometrical parameters that affect rotor axis pressure, is vital for maintaining stable pressure in the top-end region. These considerations underscore the importance of assessing how top-end pressure is influenced by rotor axis pressure. However, despite its significance for designers, direct measurement of rotor axis pressure faces substantial technical challenges. In this study, to establish the relationship between top-end pressure and rotor axis pressure, the gas flow within the entire external space of the rotor, as well as part of its internal region, was simulated using the Direct Simulation Monte Carlo (DSMC) method. Simulation results reveal that the pressure distribution inside and outside the rotor depends on the type of gas. Moreover, a correlation was derived showing that a 2.5-fold increase in top-end pressure results in a 70% rise in rotor axis pressure, while a tenfold increase in top-end pressure leads to an approximately threefold increase in rotor axis pressure.

Abstract One of the most important factors affecting the quality of images obtained from a SPECT imaging system is the physical characteristics of the collimator used. The aim of this study is to investigate the different components of the response of existing parallel-hole collimators (geometric, penetration, and scattering components) to the emission energies used in nuclear medicine imaging, and also to optimize the collimator parameters to achieve the highest value of the geometric component for high energies. The results of this study show that, considering the contribution of the geometric component, for emission energies of 68, 93, 135, 140, 159, 161, and 171 keV, the low-energy collimators LEHR and LEGP, for energies of 185 keV and 245 keV, the medium-energy collimators MEGP, and for energy of 300 keV, the high-energy collimators HEGP have the necessary efficiency. In contrast, for energies of 364 keV and 511 keV, the geometric response of any of the existing collimators is not sufficient. Hence, optimization of the collimator parameters for these two energies is necessary. According to the optimization results, high-energy collimators with the same hole size of 0.25 cm, the distance between the holes of 0.225 cm and 0.35 cm, and the collimator thickness of 7 cm and 8 cm, with geometric components of about 80% and 60%, are proposed as optimal collimators for energies of 364 keV and 511 keV, respectively.

Abstract In this study, uranium transport from a sulfate aqueous solution to an ammonium chloride solution was investigated using a hollow fiber liquid membrane (HFLM) unit containing Alamine 336. By applying different flow rates to the fiber lumen and the shell side of the hollow fiber liquid membrane module, uranium transport was examined, and the local mass transfer coefficients and resistances were calculated using the proposed empirical correlations. Through the simultaneous fitting of the obtained experimental data, the mass transfer equation coefficients were determined in terms of dimensionless numbers. The results indicated that the data fitting error was less than 6%. A comparison of the mass transfer resistances in the renewal layer, liquid membrane, and shell side revealed that uranium transport through the renewal layer is the rate-limiting step in the renewal-type hollow fiber liquid membrane system. The effect of the lumen flow rate on uranium separation from a real sample was also examined. Due to the reduction in the renewal layer thickness with increasing flow rate, uranium transport was enhanced. The results demonstrated that the hollow fiber liquid membrane consistently exhibited an efficient performance for uranium separation from real solutions. Moreover, with increasing flow rate, uranium separation from iron improves due to kinetic effects.

Abstract This research examines the Quantum Phase Transition (QPT) between spherical even-even nuclei (U(5) ) up to the critical point E(5), which has been studied using entanglement entropy in the framework of the Interacting Boson Model 2 (IBM-2). To evaluate this observable, the Tellurium isotopic chain (Te ) has been chosen. The results indicated that the entanglement entropy in the region of U(5)-SO(6) has an increasing trend. Therefore, it is predicted that the isotopes Te(116) and Te(124) are suitable candidates for the symmetry limit U(5) and the critical point E(5), respectively . And the results we obtained from this research are in very good agreement with experimental data and other studies.

Abstract The impacts of nanoparticles in radiation therapy have been investigated for many years now. The present study was conducted to investigate the effect of different physical interaction models on dose calculations using gold, hafnium and gadolinium nanoparticles. A nanoparticle with a diameter of 50 nm was simulated in a cubic water phantom. It was irradiated by protons with energies of 5, 50 and 150 MeV using Geant4 Monte Carlo toolkit. The current study considers various parameters, including the energy spectrum of secondary electrons and photons, radial dose distribution (RDD), dose enhancement factor (DEF), around the nanoparticle with three different materials and two physical interaction models. The obtained data showed that for gold nanoparticles, the Penelope model generated a greater number of secondary electrons than the Livermore model; however, for the other two nanoparticles, the Livermore model produced a greater number of secondary electrons than the Penelope model. In the RDD graphs, the Penelope model presents a 10% difference compared to the Livermore model up to a distance of 6 nm from the nanoparticle’s surface (along the radial axis in water). Furthermore, the Livermore model indicates a 16% and 10% increase in dose compared to the Penelope model. This is up to a distance of 9 nm from the surface of hafnium and gadolinium nanoparticles, respectively. In the case of DEF, the dose deposited around the gold nanoparticle was increased by 14. This is the highest amount in comparison to DEF of hafnium and gadolinium nanoparticles which is 10 and 6, respectively.

Abstract Viruses pass cell walls and enter cells using their spikes, So one of the efficient ways to stop viral infections is to disturb their spikes functionality. In this research, the process of energy absorption and transfer by SARS-COV2, MERS-COV, UK-COV, and SARS-COV spikes was studied. In this research sample viruses exposed to radioactive radiations and results were compared by Geant4-DNA and analyzed. A strategy to reduce the virus life cycle is energy absorption. In this research, the response to viruses spikes to radiation was simulated. Samples were exposed to 10 eV–2 keV electron beams. The level of Energy absorption and its relation to the number of infected patients was studied. It was concluded there is an inverse relationship between absorbed energy level and patient death.

Abstract Energy security is one of the most important factors in the sustainable development of societies. Fulfillment of goals such as economic development, increasing social well-being, and improving the quality of life depend on providing energy and guaranteeing stable and reliable, clean, and affordable resources. In recent years, the use of renewable resources has received a lot of attention to diversify their energy portfolio, reduce the harmful effects on the environment, and achieve sustainable energy. From this point of view, with the proper establishment of the nuclear fuel cycle, nuclear energy can be considered as renewable and sustainable energy in the energy portfolio and compensate for the lack of non-renewable energy in the future. The purpose of this paper is to explain the importance of a closed fuel cycle in achieving sustainable and renewable nuclear energy. Also, due to the not-very favorable situation of uranium and thorium resources in Iran, the lack of extensive international cooperation, the existence of sanctions in the provision of raw materials for nuclear fuel production, and the impossibility of guaranteeing the supply of fuel needed for nuclear energy production, the need to pay more attention to establishing a closed fuel cycle and using fast breeder reactors is proven. Paying attention to this important issue will achieve goals such as reducing the need for natural uranium, reducing the cost of nuclear waste, improving the efficiency of nuclear power plants, and producing materials required for the use of radiation in industry, medicine, and health.

Abstract Exploring and mapping radioactive environments presents potentially challenging and risky tasks. To ensure safety, the use of robots can help mitigate these risks. However, deploying a single robot may not be enough to effectively cover the entire area. Therefore, the technique of using multiple robots or a robot swarm can play a significant role in reducing time and improving the exploration and mapping process. Additionally, multi-robot systems have high reliability, and if a number of robots fail due to reasons such as radiation exposure, the remaining robots can continue the mission. This article focuses on the use of several autonomous robots simultaneously for radiation mapping and the discovery of radioactive sources. The study has examined various approaches, including the effect of the number and absorbed dose of robots. The results indicate that increasing the number of robots can enhance the speed of exploration, but the rate of increase is lower than the rate of the robot number due to the crowding of robots. To achieve optimal exploration, it is necessary to utilize more advanced models, such as movement patterns inspired by nature. This paper presents valuable insights into the coordination of collective robots for searching in radioactive environments, which could open up opportunities for the application of swarm intelligence in nuclear scenarios.

Abstract Neutron radiography (NRG) is a non-destructive imaging technique for image generation using neutron radiation. In this paper, feasibility studies of neutron radiography for IECF were performed by Geant4 Monte Carlo code. The effects of the different thicknesses of lead on the image and the detection possibility of cavities with different sizes inside a thick lead have been investigated to understand the performance of the device for neutron radiography purposes. The quality of the images was evaluated in terms of contrast. The simulation results showed the efficiency and limitations of NRG for IECF devices and the potential areas where NRG can be performed.