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A computer program for studying proton tracks in solid state nuclear track detectors was developed and described in this paper. The program was written in Fortran 90, with an additional tool for visualizing the track appearance as seen under the optical microscope in the transmission mode, which was written in the Python programming language. Measurable track parameters were determined and displayed in the application window and written in a data file. Three-dimensional representation of tracks was enabled. Examples of calculated tracks were also given in the present paper. Keywords: Solid state nuclear track detectors, CR-39, Proton tracks

X-ray and γ-ray photons have been widely used for studying radiobiological effects of ionizing radiations. Photons are indirectly ionizing radiations so they need to set in motion electrons (which are a directly ionizing radiation) to perform the ionizations. When the photon dose decreases to below a certain limit, the number of electrons set in motion will become so small that not all cells in an "exposed" cell population can get at least one electron hit. When some cells in a cell population are not hit by a directly ionizing radiation (in other words not irradiated), there will be rescue effect between the irradiated cells and non-irradiated cells, and the resultant radiobiological effect observed for the "exposed" cell population will be different. In the present paper, the mechanisms underlying photon interactions in radiobiological experiments were studied using our developed NRUphoton computer code, which was benchmarked against the MCNP5 code by comparing the photon dose delivered to the cell layer underneath the water medium. The following conclusions were reached: (1) The interaction fractions decreased in the following order: 16O > 12C > 14N > 1H. Bulges in the interaction fractions (versus water medium thickness) were observed, which reflected changes in the energies of the propagating photons due to traversals of different amount of water medium as well as changes in the energy-dependent photon interaction cross-sections. (2) Photoelectric interaction and incoherent scattering dominated for lower-energy (10 keV) and high-energy (100 keV and 1 MeV) incident photons. (3) The fractions of electron ejection from different nuclei were mainly governed by the photoelectric effect cross-sections, and the fractions from the 1s subshell were the largest. (4) The penetration fractions in general decreased with increasing medium thickness, and increased with increasing incident photon energy, the latter being explained by the corresponding reduction in interaction cross-sections. (5) The areas under the angular distribution curves of photons exiting the medium layer and subsequently undergoing interactions within the cell layer became smaller for larger incident photon energies. (6) The number of cells suffering at least one electron hit increased with the administered dose. For larger incident photon energies, the numbers of cells suffering at least one electron hit became smaller, which was attributed to the reduction in the photon interaction cross-section. These results highlighted the importance of the administered dose in radiobiological experiments. In particular, the threshold administered doses at which all cells in the exposed cell array suffered at least one electron hit might provide hints on explaining the intriguing observation that radiation-induced cancers can be statistically detected only above the threshold value of ~100 mSv, and thus on reconciling controversies over the linear no-threshold model.

Monte Carlo method was used to study the characteristics of neutron interactions with cells underneath a water medium layer with varying thickness. The following results were obtained. (1) The fractions of neutron interaction with 1H, 12C, 14N and 16O nuclei in the cell layer were studied. The fraction with 1H increased with increasing medium thickness, while decreased for 12C, 14N and 16O nuclei. The bulges in the interaction fractions with 12C, 14N and 16O nuclei were explained by the resonance spikes in the interaction cross-section data. The interaction fraction decreased in the order: 1H > 16O > 12C > 14N. (2) In general, as the medium thickness increased, the number of "interacting neutrons" which exited the medium and then further interacted with the cell layer increased. (3) The area under the angular distributions for "interacting neutrons" decreased with increasing incident neutron energy. Such results would be useful for deciphering the reasons behind discrepancies among existing results in the literature.

Radiotherapy is a common cancer treatment module, where a certain amount of dose will be delivered to the targeted organ. This is achieved usually by photons generated by linear accelerator units. However, radiation scattering within the patient's body and the surrounding environment will lead to dose dispersion to healthy tissues which are not targets of the primary radiation. Determination of the dispersed dose would be important for assessing the risk and biological consequences in different organs or tissues. In the present work, the concept of conversion coefficient (F) of the dispersed dose was developed, in which F = (Dd/Dt), where Dd was the dispersed dose in a non-targeted tissue and Dt is the absorbed dose in the targeted tissue. To quantify Dd and Dt, a comprehensive model was developed using the Monte Carlo N-Particle (MCNP) package to simulate the linear accelerator head, the human phantom, the treatment couch and the radiotherapy treatment room. The present work also demonstrated the feasibility and power of parallel computing through the use of the Message Passing Interface (MPI) version of MCNP5.

Monte Carlo method has been used to determine the efficiency for proton production and to study the energy and angular distributions of the generated protons. The ENDF library of cross sections is used to simulate the interactions between the neutrons and the atoms in a polyethylene (PE) layer, while the ranges of protons with different energies in PE are determined using the Stopping and Range of Ions in Matter (SRIM) computer code. The efficiency of proton production increases with the PE layer thickness. However the proton escaping from a certain polyethylene volume is highly dependent on the neutron energy and target thickness, except for a very thin PE layer. The energy and angular distributions of protons are also estimated in the present paper, showing that, for the range of energy and thickness considered, the proton flux escaping is dependent on the PE layer thickness, with the presence of an optimal thickness for a fixed primary neutron energy.

Radiochromic films change color upon exposures to radiation doses as a result of solid-state polymerization (SSP). Commercially available radiochromic films are primarily designed for, and have become widely used in, clinical X-ray dosimetry. However, many intriguing properties of radiochromic films are not yet fully understood. The present work aimed at developing a theoretical model at both atomic and macroscopic scales to provide a platform for future works to understand these intriguing properties. Despite the fact that radiochromic films were primarily designed for clinical X-ray dosimetry, dose-response curves for the Gafchromic EBT3 film obtained for ultraviolet (UV) radiation were employed to develop our model in order to avoid complications of ionization, non-uniform energy deposition, as well as dispersed doses caused by secondary electrons set in motion by the indirectly ionizing X-ray photons, which might introduce added uncertainties to the model and overshadow the basic SSP processes. The active layer in the EBT3 film consisted of diacetylene (DA) pentacosa-10,12-diynoate monomers, which were modelled using molecular dynamics (MD). The degrees of SSP in the atomic scale upon different UV exposures were obtained to determine the absorption coefficients of the active layer, which were then input into the finite element method (FEM). The classical steady-state Helmholtz equation was engaged to model the reflection from the active layer using the FEM technique. The multifrontal massively parallel sparse direct solver (MUMPS) was employed to solve the present numerical problem. Very good agreement between experimentally and theoretically obtained coloration in terms of net reflective optical density was achieved for different UV exposures. In particular, for UV exposures larger than ~40 J/cm2, the reflected light intensity decreased at a lower rate when compared to other UV exposure values, which was explained by the densely cross-linked structure under near-complete polymerization, and thus the lower efficiency for further bond formation between DA monomer strands.

Abstract  The absorbed fractions (AF) of electrons in sensitive layers of human respiratory tract were calculated in this paper. For that purpose the source code for simulation package PENELOPE, based on Monte Carlo method, was developed. The human respiratory tract was modeled according to ICRP66 publication, where AF of electrons was calculated using EGS4 simulation software. Some approximations used in ICRP66 were corrected in this work, and new values of AF for radon progeny are given. Minimal energy (EABS) that electron can have during transport through material is 1 keV in ICRP66, while it is set as low as 100 eV in the presented work. Lowering value of EABS gives more accurate results for AF when initial energy of electrons is below 50 keV. To represent tissue, water is used in ICRP66, while in this work epithelia tissue is used. [ABSTRACT FROM AUTHOR]

Current epidemiological approaches to radon dosimetry yield a dose conversion factor (DCF) of 4 mSv WLM−1 while the dosimetric approaches give a value closer to 13 mSv WLM−1. The present study investigated whether the application of compartment models for the bronchial (BB) and bronchiolar (bb) regions, rather than more anatomically realistic airway tube models, has brought the dosimetric DCF to the higher values. The airway tube model of the tracheo-bronchial tree was used to calculate the effective dose per unit radon exposure. All other elements of the human respiratory tract from the reports of the ICRP or NRC were adopted. A dosimetric derivation of the radon DCF using the airway tube model yielded a value of 14.2 mSv WLM−1. This value is slightly larger than, but not significantly different from, the result obtained through the ICRP 66 approach. It is concluded that utilization of the airway tube model instead of the regional ICRP 66 compartmental model cannot reconcile the gap between dose conversion factors derived from epidemiological and dosimetric approaches. [ABSTRACT FROM AUTHOR]

Abstract A model for bifurcation regions of the human tracheo-bronchial tree was developed. Equations for the surfaces are given to enable calculations of doses from alpha-particles emitted in these regions. It has been found that a bifurcation region is well approximated by a quasi-ellipsoid. The absorbed fractions of alpha-particles emitted in bifurcation regions were calculated by the Monte Carlo method. The average absorbed fraction under the bifurcation geometry is close to that found under the cylindrical geometry in the bronchial region. In the bronchiolar region, the absorbed fractions under the bifurcation geometry are up to 20% larger than those under the cylindrical geometry. [ABSTRACT FROM AUTHOR]

Computer software for calculation of the sensitivity of a CR-39 detector closed in a diffusion chamber to radon is described in this work. The software consists of two programs, both written in the standard Fortran 90 programming language. The physical background and a numerical example are given. Presented software is intended for numerous researches in radon measurement community. Previously published computer programs TRACK_TEST.F90 and TRACK_VISION.F90 [D. Nikezic and K. N. Yu, Comput. Phys. Commun. 174, 160 (2006); 178, 591 (2008)] are used here as subroutines to calculate the track parameters and to determine whether the track is visible or not, based on the incident angle, impact energy, etching conditions, gray level, and visibility criterion. The results obtained by the software, using five different V functions, were compared with the experimental data found in the literature. Application of two functions in this software reproduced experimental data very well, while other three gave lower sensitivity than experiment. [ABSTRACT FROM AUTHOR]

Conventional X-ray therapy (XRT) is commonly applied to suppress cancerous tumors; however, it often inflicts collateral damage to nearby healthy tissue. In order to provide a better conformity of the dose distribution in the irradiated tumor, proton therapy (PT) is increasingly being used to treat solid tumors. Furthermore, radiosensitization with gold nanoparticles (GNPs) has been extensively studied to increase the therapeutic ratio. The mechanism of radiosensitization is assumed to be connected to an enhancement of the absorbed dose due to huge photoelectric cross-sections with gold. Nevertheless, numerous theoretical studies, mostly based on Monte Carlo (MC) simulations, did not provide a consistent and thorough picture of dose enhancement and, therefore, the radiosensitization effect. Radiosensitization by nanoparticles in PT is even less studied than in XRT. Therefore, we investigate the physics picture of GNP-enhanced RT using an MC simulation with Geant4 equipped with the most recent physics models, taking into account a wide range of physics processes relevant for realistic PT and XRT. Namely, we measured dose enhancement factors in the vicinity of GNP, with diameters ranging from 10 nm to 80 nm. The dose enhancement in the vicinity of GNP reaches high values for XRT, while it is very modest for PT. The macroscopic dose enhancement factors for realistic therapeutic GNP concentrations are rather low for all RT scenarios; therefore, other physico-chemical and biological mechanisms should be additionally invoked for an explanation of the radiosensitization effect observed in many experiments. [ABSTRACT FROM AUTHOR]

A comprehensive study has been carried out to understand the details of structural modifications of polyallyl diglycol carbonate (PADC) polymer under the effects of different external factors. Synergistic effect of heat treatment with radiation on the polymer structure was studied. Incorporation of a neutral chromophore to understand the structural changes was attempted. Theoretical simulations were applied to get insight into the detailed aspects of structural modifications. Diverse techniques were used to characterize the samples and compare with the results of simulation studies. [ABSTRACT FROM AUTHOR]

Abstract: The present work introduces an open-source graphical user interface (GUI) computer program called DynamicMC. The present program has the ability to generate ORNL phantom input script for the Monte Carlo N-Particle (MCNP) package. The relative dynamic movement of the radiation source with respect to the ORNL phantom can be modeled, which essentially resembles the dynamic movement of source-to-target (i.e., human phantom) distance in a 3-dimensional radiation field. The present program makes the organ-based dosimetry of the human body much easier, as users are not required to write lengthy scripts or deal with any programming that many may find tedious, time consuming, and error prone. In this paper, we have demonstrated that the present program can successfully model simple and complex relative dynamic movements (i.e., those involving rotation of source and human phantom in a 3-dimensional field). The present program would be useful for organ-based dosimetry and could also be used as a tool for teaching nuclear radiation physics and its interaction with the human body., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Health Physics Society.)

Interventional radiology and cardiology are widespread employed techniques for diagnosis and treatment of several pathologies because they avoid the majority of the side-effects associated with surgical treatments, but are known to increase the radiation exposure to patient and operators. In recent years many studies treated the exposure of the operators performing cardiological procedures. The aim of this work is to study the exposure condition of the medical staff in some selected interventional radiology procedures. The Monte Carlo simulations have been employed with anthropomorphic mathematical phantoms reproducing the irradiation scenario of the medical staff with two operators and the patient. A personal dosemeter, put on apron, was modelled for comparison with measurements performed in hospitals, done with electronic dosemeters, in a reduced number of interventional radiology practices. Within the limits associated to the use of numerical anthropomorphic models to mimic a complex interventional procedure, the personal dose equivalent, Hp(10), was evaluated and normalised to the simulated Kerma-Area Product, KAP, value, indeed the effective dose has been calculated. The Hp(10)/KAPvalue of the first operator is about 10 μSv/Gy.cm2, when ceiling shielding is not used. This value is calculated on the trunk and it varies of +/−30% moving the dosemeter to the waist or to the neck. The effective dose, normalised to the KAP value, varies between 0.03 and 0.4 μSv/Gy.cm2. Considering all the unavoidable approximation of this kind of investigations, the comparisons with hospital measurement and literature data showed a good agreement allowing to use of the present results for dosimetric characterisation of interventional radiology procedures. [ABSTRACT FROM AUTHOR]

Some concepts in nuclear radiation physics are abstract and intellectually demanding. In the present paper, an "MCHP platform" (MCHP was an acronym for Monte Carlo simulations + Human Phantoms) was proposed to provide assistance to the students through visualization. The platform involved Monte Carlo simulations of interactions between ionizing radiations and the Oak Ridge National Laboratory (ORNL) adult male human phantom. As an example to demonstrate the benefits of the proposed MCHP platform, the present paper investigated the variation of the absorbed photon dose per photon from a 137Cs source in three selected organs, namely, brain, spine and thyroid of an adult male for concrete and lead shields with varying thicknesses. The results were interesting but not readily comprehensible without direct visualization. Graphical visualization snapshots as well as video clips of real time interactions between the photons and the human phantom were presented for the involved cases, and the results were explained with the help of such snapshots and video clips. It is envisaged that, if the platform is found useful and effective by the readers, the readers can also propose examples to be gradually added onto this platform in future, with the ultimate goal of enhancing students' understanding and learning the concepts in an undergraduate nuclear radiation physics course or a related course. [ABSTRACT FROM AUTHOR]

Copyright of Kirkuk University Journal for Scientific Studies is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study used an analytical computational model to evaluate safe zones in contaminated areas that may result from a hypothetical significant off-site release from a nuclear power plant. The model, considering local atmospheric stability, wind direction, and location, calculates the expected total effective dose equivalent (TEDE) and potential safety zones. This research, focused on an area near a nuclear facility affected by an accidental release, used SCALE and HotSpot Health Physics codes to simulate the reactor's core inventory content and off-site release. This study's findings underscore that the risk of developing solid cancer (testing morbidity) is influenced by both local atmospheric stability and the composition of the potentially affected population (primarily age and sex). These findings, backed by an analytical approach, can significantly influence logistical and operational planning. The utilization of computer simulations can also aid in creating flexible response scenarios to real events. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is an important source of human internal exposure to radionuclides and heavy metals because, worldwide, a large fraction of the population consume rice as their daily basic diet. In this study, the levels and correlation of natural radioactivity (232Th, 226Ra and 40K) and heavy metals (Pb, Ni and Cd) in local rice sold in Enugu urban markets, a southeastern part of Nigeria, were examined. Possible health implications were also evaluated. The mean activity concentrations were estimated to be 235.81 ± 12.93, 54.29 ± 8.08 and 63.70 ± 3.93 Bqkg−1 for 40K, 226Ra and 232Th respectively. Obtained values were higher than values reported in the literature for rice in other locations. The estimated committed effective doses for 226Ra and 232Th exceeded the global ingestion dose average of 0.12 mSvy,–1 whereas that of 40K is below the 0.17 global average. The average concentrations of the metals were estimated to be 0.41, 3.70, and 0.02 mgkg–1 for Pb, Cd and Ni, respectively, with only Ni having an average concentration below the threshold food safety limit of FOA/WHO. Only the concentrations of Cd were of significant levels with their health risk indices exceeding the tolerable reference levels for both children and adult. Only the pairs, 232Th-Ni and Pd-Cd, correlated significantly (p < 0.05) which implies common sources. Multivariate principal component analysis indicated common natural sources for 226Ra, 232Th and Ni in local rice, possibly of lithogenic and paedogenic in nature. It is believed that the results of this study will be valuable to the radiological and toxicological food safety and policy framework of WHO/FAO in Nigeria and the rest of the world. [ABSTRACT FROM AUTHOR]

The efficacy of filters to trap volatile radiotoxic nuclear fission products depends on the thermodynamic stability of these species within the filter material. Using atomic scale modeling based on density functional theory together with a dispersion correction, we predict the structures and energies of volatile fission product atoms and molecules trapped by a crystalline organic electride Cs+(15C5)2•e−. Endothermic encapsulation energies indicate that Kr and Xe are not captured by this electride. Conversely, encapsulation is very strong for Br, I, and Te, with respect to atoms and dimers as reference states, leading to the formation of trapped Br−, I−, and Te− ions. While both Rb and Cs are encapsulated exothermically (without significant charge transfer), their encapsulation is markedly weaker than that calculated for Br, I, and Te. Encapsulation of homonuclear dimers (Br2, I2, and Te2) as anionic molecular species is thermodynamically favorable, though they will disproportionate if sufficient encapsulation sites are available. Conversely, encapsulation of heteronuclear dimers (Rb–Br, Rb–I, Cs–Br, and Cs–I) is unfavorable with respect to their bulk solids as reference states. [ABSTRACT FROM AUTHOR]

Environmentally hazardous radioactive isotopes of iodine may be released from a nuclear power plant as a by-product of uranium fission. The efficient and safe capture of volatile radioiodine is of great significance in the history of nuclear power plants. Due to its high volatility and carcinogenic characteristics, elimination of iodine gas (I 2 ) from air is the need of the hour from an environmental and health point of view. In this work, the trapping of molecular iodine has been studied using porous adsorbents such as activated carbon (AC) and activated carbon impregnated with metals or triethylenediamine (TEDA). Impregnated activated carbons (IACs) chemically react with iodine through SN 2 mechanism. The physicochemical and structural characterization of raw activated carbon (RAC) and impregnated activated carbons (IACs) was done by AAS, SEM, EDX, BET, and XRD. The finding of the breakthrough experimental adsorption showed that the gaseous iodine (50 ppm) equilibrium adsorption capacity of the raw AC before and after impregnation increased from 180 to 1044 mg/g mL at a condition of 60 °C. Furthermore, metal IAC was highly adsorbent at high temperatures (80 °C) due to its stability, and it adsorbed up to 576 mg/g mL iodine at a maximum. The breakthrough study examined that the adsorption capacity of iodine enhanced up to 19% for metal and 26% for metal-TEDA IAC as compared to RAC. Adsorption equilibrium data were well described by the Langmuir model, and the kinetics study was demonstrated by the second-order model. Thermodynamic parameters demonstrated that this is an exothermic and spontaneous reaction. This study explored the parameters of a filter such as adsorption capacity and saturation time at which no more pollutant gas can be captured. Finally, the findings demonstrate that these adsorbents may be capable of adsorbing large amounts of gaseous iodine., Competing Interests: Declarations. Ethical approval: We confirm that this work is original and has neither been published nor is currently considered for publication elsewhere. We confirm that the co-author acknowledges her participation in conducting the research leading to this manuscript and has agreed to its submission to be considered for publication. The research meets the ethical guidelines, including adherence to the legal requirements of the study. Per the journal’s style and format requirements, we have prepared the manuscript, including figures and tables. Consent to participate: All authors have agreed to contribute to this study. Consent for publication: The authors agree to publish. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

For ultrasound diagnosis, a gel is applied to the skin. Ultrasound gel serves to block air exposure and match impedance between the skin and the probe, enhancing imaging efficiency. However, if use of the ultrasound gel exceeds a certain period of time, it may dry out and be exposed to air, causing impedance mismatch and reducing imaging resolution. In such cases, the use of a soft, solid gel proves advantageous, as it can be employed for an extended period without succumbing to the drying phenomenon and can be reused after disinfection. Its soft consistency ensures excellent skin adhesion. Our soft solid gel demonstrated approximately 1.2 times better performance than water, silicone, and traditional ultrasound gels. When comparing the dimensions of grayscale, dead zone, vertical, and horizontal regions, the measurements for the traditional ultrasound gel were 93.79 mm, 45.32 mm, 103.13 mm, 83.86 mm, and 83.86 mm, respectively. In contrast, the proposed soft solid gel exhibited dimensions of 105.64 mm, 34.48 mm, 141.1 mm, and 102.8 mm. [ABSTRACT FROM AUTHOR]

Cylindrical diffusion chamber for radon measurement equipped with nuclear track detector (CR-39) and electretis considered in this work. Electret is electrostatic analogous of permanent magnet which preserves constant and strong electric field for long time period. Electrets were used to attract radon progeny formed in a cup where CR-39 was placed for radon measurements. In this way the sensitivity of detector could be increased by bringing progeny just in front of detector in more convenient measuring geometry. Influence of distance between electret and detector on sensitivity of such equipment has been investigated theoretically. Different geometrical setups of detector and electret were tested in order to optimize this kind of device. Some results are presented in this report. [ABSTRACT FROM AUTHOR]

This study examined the radioactivity levels of soil samples within selected solid mining sites in Nigeria using high-purity germanium (HpGe) detector. Sixty soil samples in all were collected from the 10 solid mineral mining sites investigated and six samples were collected as control samples from non-mining environment for analyses. The results of the activity concentration values obtained for 40K, 226Ra and 232Th are 100.22 Bq kg−1, 33.15 Bq kg−1 and 77.31 Bq kg−1, respectively. The 226Ra and 40K activities were found to be within the United Nation Scientific Committee on the Effects of Atomic Radiation acceptable permissible limit, but the 232Th mean value was above the permissible limit of 30 Bq kg−1 for the public. In comparison, 40K, 226Ra and 232Th soil samples mean activity concentrations were higher than the control soil samples values by 48.6%, 43.7% and 62.3%, respectively. The results of estimated radiation hazard indices indicate average values of 150.72 Bq kg−1, 68.40 nGyh−1 n G y h − 1 , 83.65 µSvy−1 and 454.70 µSvy−1 for the Radium Equivalent (Raeq R a e q ), Absorbed Dose Rate (D), Dose Equivalent (AEDE) and Annual Gonadal Equivalent Dose (AGED), respectively. The mean values for External Hazard Indices (Hex, Hin), Representative Gamma index ( I γ ) and Excess Life Cancer Risk (ELCR) were 0.41, 0.50, 1.06 and 0.29 × 10−3, respectively. The statistical analysis shows positive skewness. [ABSTRACT FROM AUTHOR]

Although more than 30 years have passed since the Chernobyl accident, artificial radionuclides are still present in the soil. Especially, 137Cs is harmful to human health and contamination due to 137Cs is high. The topsoil samples were collected from various locations in Konya, Turkey. 137Cs activity concentrations were measured using coaxial high-purity germanium gamma-ray spectrometry. 137Cs activity concentrations in the surface soil samples ranged from 0.74 ± 0.08 to 12.88 ± 0.86 Bq kg−1 dry weight (d.w.). The absorbed dose rate and the annual effective dose rates for outdoor and indoor air were estimated. The mean values of the absorbed dose rate and the outdoor and the indoor annual effective dose rates were found as 0.09 nGy h−1, 0.11 μSv y−1, and 0.43 μSv y−1, respectively. The obtained activity concentrations and annual effective dose rates were compared with other studies. The spatial distributions of 137Cs activity concentrations and dose rates were plotted using the Surfer Program. The Kriging interpolation method is used to obtain the distribution maps of 137Cs radionuclide. Frequency distribution and quantile-quantile plots were carried out. [ABSTRACT FROM AUTHOR]

A corrugated surface long period grating (LPG) was fabricated on a flat-shaped plastic optical fiber (POF) as a refractive index (RI) sensor by a simple pressing with the heat pressure and mechanical die press print method. The light propagation characteristics of an LPG imprinted on a multi-mode POF were analyzed by the method of geometrical optics. Theoretical and experimental results showed that the structural parameters of the sensor affected the RI sensing performance, and the sensor with a thinner flat thickness, a deeper groove depth of the corrugated surface LPG, and a longer LPG exhibited better RI sensing performance. When the POF with a diameter of 1 mm was pressed with the heat pressure to a flat shape with a thickness of 600 µm, an LPG with a period of 300 µm, a groove depth of 200 µm, and a length of 6 cm was fabricated on it, and the RI sensitivity of 1447%/RIU was obtained with a resolution of 5.494×10−6 RIU. In addition, the influences of the POF cladding, tilting of LPG, and bending of the sensing structure were investigated. The results demonstrated that after removing the cladding and tilting or bending the LPG, the RI sensing performance was improved. When the LPG imprinted on the flat-shaped POF was bent with a curvature radius of 6/π cm, the highest sensitivity of 6 563%/RIU was achieved with a resolution of 2.487×10−9 RIU in the RI range of 1.3330–1.4230. The proposed sensor is a low-cost solution for RI measurement with the features of easy fabrication, high sensitivity, and intensity modulation at the visible wavelengths. [ABSTRACT FROM AUTHOR]

After the Chernobyl accident, a designated area of ~1000 m2 within the University farm of Aristotle University of Thessaloniki in Northern Greece was utilized as a test ground for radioecological measurements. The profile of 137Cs in the soil was monitored from 1987 to 2023, with soil samples collected in 5-cm-thick slices (layers) down to a depth of 30 cm. The mean total deposition of 137Cs in the area, backdated to the time of the Chernobyl accident, was determined to be 18.6 ± 1.8 kBq m−2 based on four follow-up profile measurements of 137Cs in the soil for the years 2022 and 2023. It is noteworthy that this value is similar the total deposition at the site, which was independently measured to be about 20 kBq m−2 during the first year after the Chernobyl accident. The fractional contribution of each soil layer (e.g. 0–5 cm, 5–10 cm, 10–15 cm, etc.) to the total deposition of 137Cs (0–30 cm) is presented and analyzed. A compartment model was utilized to forecast the temporal evolution of fractional contributions of the different soil layers to the total deposition of 137Cs (0–30 cm). In this model, each soil layer is represented as a separate compartment. The model assumes that the transfer rates between adjacent compartments are equal. The agreement between the measured fractional contributions and the model predictions suggests that the compartment model with equal transfer rates can capture the broad patterns of 137Cs migration within the soil layers over the long period of 1987–2023. However, the use of a second compartment model with increasing transfer rates between consecutive soil layers did not align with the observed outcomes. This indicates that diffusion may not be the primary migration mechanism over the 36-y period covered by our study. [ABSTRACT FROM AUTHOR]

This investigation quantifies the activity concentrations of natural radionuclides ( 226 Ra, 232 Th, and 40 K) in the soils and certain rocks of the Koytash-Ugam Range, Uzbekistan, and assesses their radiological risks. Gamma-spectrometric analysis of soil and rock samples revealed activity concentrations ranging from 456.2 ± 56.0 to 813.9 ± 76.0 Bq kg -1 for 40 K, 18.2 ± 6.3 to 70.0 ± 12.0 Bq kg -1 for 226 Ra, and 30.1 ± 2.9 to 57.9 ± 10 Bq kg -1 for 232 Th. This data indicates a heterogeneous distribution of radionuclides, informing radiation safety and health risk assessments on a global scale. The calculation of radiological hazard indices, including the alpha-index (ranging from 0.09 to 0.35), gamma-index (ranging from 0.40 to 0.73), and both internal (ranging from 0.40 to 0.54) and external (ranging from 0.36 to 0.54) hazard indices, was undertaken to ascertain potential health risks. The radium equivalent activity ranged from 108.4 to 199.3 Bq kg -1 , and the absorbed dose rates were 51.0-93.3 nGy h -1 indoors and 96.6-178.2 nGy h -1 outdoors. These metrics underlie the estimated annual effective dose of 536.5-988.5 × 10 -3  mSv y -1 , highlighting the variability in radiation exposure. Additionally, the potential lifetime cancer risk was projected at 1770.4 to 3262.0 per million, with an annual gonadal dose equivalent of 361.9 to 655.5 μSv y -1 , reflecting natural background radiation influence. The results underscore the importance of safe material use in construction and the necessity for routine natural radioactivity monitoring. Radon flux density (RFD) values within acceptable construction limits (26-176 mBq m -2  s -1 ) suggest the area's suitability for development, considering recommended safety guidelines. This study not only aids local environmental and public health frameworks but also enriches the international knowledge base, facilitating comparative studies for the advancement of global radiation protection standards. Through a detailed examination of radionuclide distribution in an under-researched area, our research highlights the critical need for integrated international approaches to natural radiological hazard assessment., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Copyright of Kirkuk University Journal for Scientific Studies is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Kirkuk University Journal for Scientific Studies is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Commercially available radiochromic films are primarily designed for clinical X-ray dosimetry. These films change color upon exposures to radiation as a result of solid-state polymerization (SSP). Built on a previous model developed for SSP upon exposures to ultraviolet (UV) radiation, a new model was developed in the present work for X-ray-induced coloration in Gafchromic EBT3 films. Monte Carlo simulations using the Monte Carlo N-Particle (MCNP) code were employed to model the transport and interaction of photons and the generated secondary electrons within the film active layer. The films were exposed to continuous-energy photon beams. The dose DE in the external radiation detector (i.e., ionization chamber) was determined and the realistic dose DA in the film active layer was then obtained using the calibration coefficient R (=DA/DE). The finite element method (FEM) was used to solve the classical steady-state Helmholtz equation using the multifrontal massively parallel sparse direct solver (MUMPS). An extensive grid independence test was carried out and the numerical stability of the present model was ensured. The reflected light intensity from the film surface was used to theoretically obtain the net reflective optical density of the film exposed to X-ray. Good agreement was obtained between the experimental and theoretical results of the net reflective optical density of the film. For X-ray doses >~600 cGy, due to the already formed densely cross-linked structure in the active layer of the EBT3 film so further bond formation was less likely, the reflected light intensity from the film surface increased at a relatively lower rate when compared to those for dose values <~600 cGy. [ABSTRACT FROM AUTHOR]

Model refinements for the edge illumination x-ray phase contrast imaging method have been developed to improve simulation accuracy for high energy, polychromatic beams. High-energy x rays are desirable in imaging due to their penetrative power and, for biological samples, their lower dose deposition rate. Accurate models of such scenarios are required for designing appropriate imaging systems and to predict signal strength in complex settings such as clinical imaging or industrial quality assurance. When using optical components appropriate for high-energy x rays in a non-synchrotron setting, system performance was observed to deviate from that predicted by existing models. In this work, experimental data utilizing increasing thicknesses of a known filter material are used to illustrate the limitations of existing models and as validation for the new modeling features. Angular filtration of the cone beam was observed to be the most significant effect; however, specific features of the source and detector are also shown to affect system performance. We conclude by showing that a significantly improved agreement between experimental and simulated data is obtained with the refined model compared to previously existing ones. [ABSTRACT FROM AUTHOR]

There is a growing necessity to develop revolutionary neutron detectors for nuclear energy, nuclear physics, medical physics, astrophysics, biological imaging, nonproliferation, and national security. The often-used Helium-3 (He-3) neutron detector is becoming increasingly difficult to obtain due to He-3 shortages. As an emerging oxide semiconductor material, Ga2O3 exhibits excellent physical properties. These physical merits enable Ga2O3's potential as a high-performance semiconductor neutron detector for extreme condition applications. Here, two approaches are explored, i.e., applying an exterior conversion layer of boron-10 (B-10) on Ga2O3 and directly doping B-10 into Ga2O3 to demonstrate Ga2O3's capability for neutron detection. Using Monte Carlo simulation, we show the distinct difference in neutron detection efficiency of Ga2O3 when applying direct doping of B-10 into Ga2O3 vs applying a uniform B-10 conversion layer on top of Ga2O3. Our results exhibit that the theoretically predicted maximum doping level of B-10 in Ga2O3 does not lead to the same detection efficiency as that of a simple B-10 conversion layer when detecting 480 keV gammas. Except for the most thermalized neutrons at 0.01 eV, direct doping simulations are not able to achieve comparable results to that of the conversion layer method. [ABSTRACT FROM AUTHOR]

We fabricate a nanocomposite (NC) of polycarbonate (PC), Zinc sulfide (ZnS) and Nickel oxide (NiO) nanoparticle by the sol-gel and ex-situ casting processes. We trust that this study is novel in the area of the impact of laser on such NC. The Rietveld alteration of XRD records indicates that both the prepared ZnS and NiO have a nano-nature of an average particle size of 4 and 18 nm. Samples of the PC/ZnS-NiO NC films are exposed to numerous laser fluences (4 – 30 J/cm2). We investigate the resulting outcome of the laser exposure on the optical behavior of the NC films, using ultraviolet spectroscopy (UVs). Upon raising the fluence up to 30 J/cm2, both the indirect and direct band gaps reduce. The Urbach energy exhibits a reverse trend. This can be attributable to the domination of chain crosslinks. Also, we detect the nature of microelectronic transitions, using the optical dielectric loss εʺ and find that the PC/ZnS-NiO NC films possess direct allowed transitions. Also, we study the laser induced modifications in the optical conductivity and dielectric parameters. Moreover, the optical coloration changes between the exposed samples and pristine are estimated. The pristine NC sample is uncolored. It shows significant color alterations upon the laser exposure. The induced improvements in the optical characters suggest that the laser is a convenient mean that permits the use of PC/ZnS-NiO NC in the optoelectronic devices. [ABSTRACT FROM AUTHOR]

This paper presents an assessment of nuclear reaction yields of protons, α -particles, and neutrons in human tissue-equivalentmaterial in proton therapy using a simulation with Geant 4. In this study, we also check an enhancement of nuclear reactions due to the presence of Bi, Au, 11 B, and 10 B radiosensitizer nanoparticles. We demonstrate that a proton beam induces a noticeable amount of nuclear reactions in the tissue. Nevertheless, the enhancement of nuclear reaction products due to radiosensitizer nanoparticles is found to be negligible. [ABSTRACT FROM AUTHOR]

We investigate the spatiotemporal distribution of the radionuclides including iodine-131 (131 I) and cesium-137 (137 Cs), transported to Qatar from fictitious accidents at the upwind Barakah nuclear power plant (B-NPP) in the United Arab Emirates (UAE). To model the dispersion of radionuclides, we use the Lagrangian particle–air parcel dispersion model FLEXible PARTicle (FLEXPART) and FLEXPART coupled with the Weather Research and Forecasting model (FLEXPART–WRF). A four-member mini-ensemble of meteorological inputs is used to investigate the impact of meteorological inputs on the radionuclide dispersion modeling. The mini-ensemble includes one forecast dataset (Global Forecast System, GFS) and three (re)analysis datasets (native-resolution and downscaled NCEP final analysis – FNL, as well as downscaled ERA5). Additionally, we explore the sensitivity of the radionuclide dispersion simulations to variations in the turbulence schemes, as well as the temporal and vertical emission profiles, and the location of emission sources. According to the simulated age spectrum of the Lagrangian particles, radionuclides enter southern Qatar about 20 to 30 h after release. Most of the radionuclide deposition in the study area occurs within 80 h after release. The most populated areas of Qatar coincide with moderate 131 I concentrations and 137 Cs deposition, while uninhabited areas in southern Qatar receive the highest amounts. A larger number of long-lived particles is found in the FNL-based simulations, which is interpreted as a greater dispersion of particles at a greater distance from the emission location. The highest simulated 131 I and 137 Cs deposition shows a pronounced spatiotemporal pattern. The largest impacts are found in the south and southeast of Qatar, during the early daytime development of the boundary layer, and during the cold period of the year. The results show remarkable differences in the spatiotemporal distribution of 131 I and 137 Cs simulations based on the FNL and GFS datasets, which share a common base meteorological model. As part of a sensitivity analysis involving different model setups, changing the emission point from B-NPP to Bushehr NPP (Bu-NPP) results in a reduced transfer of radioactive materials to Qatar, except in the spring season. Bu-NPP simulations reveal distinct spatial patterns, with peak 131 I concentrations and 137 Cs deposition observed in northern and eastern Qatar during winter and spring. [ABSTRACT FROM AUTHOR]