Radiation Physics and Engineering

Abstract The production of light, energetic and low-flux ions as a secondary beam caused by nuclear reaction can be used in various branches of nuclear physics. Due to the limited availability of energy in small laboratories equipped with electrostatic accelerators, accessing energetic light particles is crucial. For this purpose, selected nuclear reactions were introduced. In this research, primary proton, deuterium and helium-3 beams with energy less than 2 MeV were used for samples with a thickness of 10¹⁹ atom.cm^-2 and the yield of reactions was obtained. The laboratory setup was designed in such a way that in addition to the access to the nuclear reaction products with a suitable yield, favorable conditions were provided for the extraction and transfer of the reaction products as well as their interaction with the sample. In these exothermic nuclear reactions, the yield is in the order of 10⁶ particles and secondary proton and alpha particles with energies of 4 to18.5 MeV have been obtained. Also, the selected reactions are in accordance with the radiation protection protocols of similar laboratories.

Abstract Due to the diverse uses of research reactors compared to power reactors, a variety of safety aspects must be considered in their design and operation. On the other hand, due to the high age of a large percentage of these reactors, the need to update them in order to respond to the growing needs of today's society is inevitable. One of the items that increase the features in terms of proliferation, economy, usability, security and nuclear to meet the requirements of today's society is core conversion. The advantages and necessities of using new fuel in research reactors include the possibility of forming a more compact core, reducing operating costs, reducing security challenges, protection, environmental effects, transportation and end-of-cycle processes. In this study, the roadmap for research reactors core conversion is drawn considering all aspects of this issue which would be very useful for research reactor plan of any country especially our country.

Abstract The Persistent development of quick and accessible readout tools promises to remove one of the barriers to the adoption of gel dosimetry as an applicable method in treatment clinics. Research and development in the imaging of polymer gel dosimeters continues with a focus on imaging in three dimensions. Each technique comes with its own set of advantages and challenges. In gel dosimeter research, efforts have been made to identify and develop alternative imaging methods for polymer gel dosimeters. Gel dosimeters can obtain reliable and accurate three-dimensional dose distributions from the correlation of different polymerization stages caused by radiation. The irradiated samples are examined using magnetic resonance imaging, optical computed tomography, and X-ray computed tomography. This research describes the basic features of imaging devices and the readout of irradiated dose data. Costs, availability, portability, contrast and resolution, high-resolution image reconstruction algorithm, and image reconstruction time of radiation absorption dosimeters for imaging devices are investigated in this research. This review has been done to present the mentioned imaging features and review the research done in this field for the optimal use of different imaging methods.

Abstract Inverse beta decay (IBD) in plastic scintillators is one of the most commonly used methods for detecting reactor antineutrinos. Cosmic muon signals due to the IBD compared to those generated by antineutrinos are still the main challenge in these types of detectors. The IRAND (IRan ANtineutrino Detector) is currently being designed and implemented with the constraint of reducing the required hardware, and at the same time, improving the antineutrino detection efficiency. Imbalanced classification is one of the software methods in machine learning that deals with imbalanced data, such as muon and antineutrino. Using the IRAND-Sim simulation package based on the Geant4 toolkit presented in our previous research, the spectra and angular distribution of antineutrinos and muons can be calculated. However, in this study, the memory management techniques to handle the dataset due to a large number of muons have been used, and also two separate methods have been used in the imbalanced classification for discriminating muon and antineutrino events. The results show that this approach by combining real and simulated data is very efficient, and the imbalanced nature can be reduced to achieve better classifier performance.

Abstract While ionizing radiation plays a pivotal role in the precise diagnosis and treatment, it concurrently engenders risks, including an elevated incidence of cancer. The research speaks to the discernible decline in quality assurance programmes and dose measurement endeavors within Nigerian imaging facilities, with a substantial portion lacking established protocols for routine machine calibration and dose measurement. This study encompasses a large-scale survey involving 307 adult patients undergoing routine X-ray procedures in two hospitals in Nigeria. Thermo-luminescent dosimeters (TLDs) were used for measuring Entrance Skin Dose (ESD) of consenting adult patients. The mean ESD values ranged from 1.16 mGy to a maximum of 3.94 mGy. Notably, these values were predominantly below the dose reference levels (DRLs) established by reputable bodies such as NRPB, CEC, IAEA, and UK for most examinations. The main purpose of this study was to determine the diagnostic reference level (DRL) for routine digital radiography examinations in Nigeria.

Abstract In this paper, the growth of transverse-longitudinal coupled electromagnetic modes in the interaction of high-intensity lasers with dense plasma is investigated. Using kinetic theory and solving the scattering relationship for the Vlasov-Maxwell system, the collision effects on the growth of the electromagnetic mode are studied. The anisotropic distribution function considers the effects of body stress due to laser ponderomotive force and plasma density gradient. The results show that a 99% reduction in frequency in the beam path in dense plasma leads to an 88\% increase in the growth rate of unstable modes. Increasing the density prevents immediate cessation and enhances the growth of unstable modes. Increasing the density gradient by 99\%, the instability rate maximum will increase by 88\%. Overall, this paper provides insights into the effects of collision and anisotropic distribution function on the growth of transverse-longitudinal coupled electromagnetic modes in dense plasma. Overall, this paper provides insights into the interplay between various phenomena such as body stress, collision, and electromagnetic modes in dense plasma.

Abstract In this study, the objective was to separate cadmium isotopes using the Q-cascade approach. The optimal value of the parameter M* was determined by minimizing the function (∑Lε₀²)/2P within the Q-cascade. To overcome computational challenges, the Newton-Raphson solver and direct substitution algorithm were employed to solve the system of nonlinear equations. The direct substitution method was used to provide a suitable initial guess for the Newton-Raphson method. Validation of the developed algorithms using stable cadmium isotopes showed that the value of M* undergoes slight changes with variations in the target isotope concentration in the product and waste streams. For enriching Cd-106 in the product, M* was approximately 108.5, corresponding to the average molar mass of Cd-106 and Cd-111. As the target isotope concentration in the product increases, the number of enrichment stages increases more steeply compared to the number of stripping stages. Similarly, increasing the Cd-116 enrichment in the waste leads to a larger increase in the number of stripping stages compared to enrichment stages.

Abstract High-voltage semiconductor devices are vulnerable to Single Event Burnout (SEB) as a result of interactions with Galactic Cosmic Rays (GCR). SEB is a permanent failure triggered by the passage of a single particle during the turn-off state of the device. This paper investigates SEB in a PiN diode induced by various ions in space through simulation. The Linear Energy Transfer (LET) of the ions studied was determined using SRIM. Additionally, the electrical properties of the device due to irradiation were analyzed using the Silvaco TCAD tool. The key indicator of SEB occurrence is the threshold voltage of SEB (V_SEB). Therefore, the correlation between the ion's LET and V_SEB was investigated. The results indicate that the most sensitive region is in the middle of the device, and SEB is caused by avalanche multiplication of ion-generated carriers. It was also observed that the V_SEB decreased from 3200 V to 2100 V; as the LET increased from 0.19 to 58 MeV.cm².mg^-1 for He and Ta, respectively. Consequently, ions with higher LET values can cause the device to burnout at a lower V_SEB level, increasing the device’s sensitivity to SEB.