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- MakaleAçık Erişim2026Monte Carlo calculation of geometry-dependent true coincidence summing correction factors for the gamma-rays of 214Bi in HPGe detectors
Çelik, Necati
True coincidence summing (TCS) effects in gamma-ray spectrometry introduce significant systematic uncertainties in activity determinations, particularly for radionuclides with complex decay schemes such as 214Bi. This study presents a comprehensive Monte Carlo investigation of TCS correction factors (CFs) for seven major gamma-ray lines of 214Bi. The primary contribution of this study is the systematic decoupling of detector geometry effects: nine distinct HPGe detector configurations were simulated with varying crystal dimensions, dead layers, and hole geometries, followed by an isolated analysis of crystal radius versus crystal length contributions for both point and extended source geometries. The decay scheme of 214Bi was meticulously modeled using Nucleide 2000 data, incorporating all beta branches, gamma transitions, internal conversion coefficients, and cascade probabilities to ensure high-fidelity representation of the decay scheme. Results demonstrate that crystal radius exerts a substantially stronger influence on TCS CFs than crystal length, with point source values at 609.3 keV increasing by 18.2% across the radius range of 2.1–4.5 cm, compared to only 3.7% variation across the length range of 3–11 cm. Extended source geometries reduce TCS CFs by 5%–11% compared to point sources across all configurations, highlighting the mitigating effect of distributed sources. Energy-dependent behavior is also evident: the 609.3 keV line exhibits strong summing-in (CF > 1.3 for large detectors), while the 1377.7 keV line shows dominant summing-out (CF < 0.86). These findings provide gamma-ray spectrometrists with insight into the relative importance of detector dimensions for TCS effects, suggesting that crystal radius is the primary geometric parameter influencing coincidence summing corrections. The observed trends illustrate how TCS corrections vary with detector dimensions, offering spectrometrists a basis for understanding the relative sensitivity of these corrections to different geometric parameters.
- MakaleAçık Erişim2026Computational analysis of radiation shielding properties of BaO-modified magnesium borophosphate glasses based on WinXCOM and EGS4 Monte Carlo simulations
Düzgün, İbrahim; Çelik, Necati; Kaya, Selim
The increasing use of ionizing radiation in medical, industrial, and nuclear applications necessitates the development of advanced and environmentally friendly shielding materials. In this study, the gamma-ray shielding performance of BaO-modified magnesium borophosphate glasses with compositions xBaO–30MgO–10P2O5–(50−x)B2O3–10Na2O (x = 0–35 mol%) was theoretically investigated. The radiation attenuation properties were evaluated over a wide photon energy range (59.54–2000 keV) using the WinXCOM database and Monte Carlo simulations based on the EGS4 code. Key shielding parameters, including mass attenuation coefficient (μ/ρ), half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), radiation protection efficiency (RPE), and gamma-ray kerma coefficients, were determined. The results indicate that increasing BaO content enhances the attenuation capability of the glass system, particularly in the low and medium photon energy regions, due to increased density and effective atomic number. A good agreement between WinXCOM and EGS4 results confirms the reliability of the applied theoretical approaches. These findings suggest that BaO-modified magnesium borophosphate glasses are promising candidates for radiation shielding applications.
- MakaleYalnız künye2026Influence of Compton scattering and pair production in radiation shielding of Eu-doped Bi-2223 ceramics
Doğruer, Musa; Kaya, Selim
The gamma-ray attenuation behavior of europium (Eu)-doped Bi-2223 ceramic superconductors has been investigated in detail in this work in the photon energy range of 59.54 to 1332 keV. The WinXcom database was used to rigorously estimate the mass attenuation coefficients (μ/ρ), which are the main quantifiers of the probability of photon–matter interaction. Stochastic modeling based on the EGS4 Monte Carlo transport technique was then used to confirm the results. Key shielding metrics such as the mean free path (MFP), radiation protection efficiency (RPE), half-value layer (HVL), and gamma-ray kerma coefficients (kγ) are derived from these coefficients and offer information about the material’s inherent ability to dissipate or attenuate incident photon flux. Additionally, the effective atomic number (Zeff) was established to elucidate the role of compositional heterogeneity and atomic cross-section weighting in regulating photon absorption and scattering probabilities. Concurrently, the macroscopic fast neutron removal cross-sections (ΣR) were computed to measure the dual shielding capacity of the ceramics being studied against electromagnetic radiation and neutrons. The findings showed that although Eu doping led to a minor increase in the effective atomic number and μ/ρ values at lower photon energy, it also resulted in greater HVL and MFP values, particularly at higher energies. The total shielding performance decreases due to the decrease in bulk density, even though the addition of Eu results in better mass attenuation coefficients. The μ/ρ values of Eu-doped Bi-2223 ceramics exhibit high agreement and increase from 2.753 to 3.212 cm2 g−1 at 59.54 keV with increasing Eu content. These values were produced using EGS4 simulations and verified using WinXCOM in the 59.54–1332 keV energy range. This suggests that europium’s higher atomic number enhances photon absorption at lower energies. The study also demonstrates that the Eu-0 sample has the strongest neutron shielding capabilities and the highest radiation protection efficiency (RPE).
- MakaleAçık Erişim2024Fatigue and tensile behaviour of Ti+TiN+Ti+TiVN multilayer nitride films coated on AZ91 magnesium alloy by closed field unbalanced magnetron sputtering
Alibeyoğlu, Fatih; Karabudak, Filiz; Yeşildal, Ruhi; Balcı, Arif; Efeoğlu, İhsan; Ateş, Onur Kazım
Despite their extensive use in the automotive and aerospace industries, Mg and Mg alloys, which are light metals, exhibit low fatigue and tensile strength. In this study, transition metal-nitride (TMN) multilayer coatings (Ti+TiN+Ti+TiVN) were coated twice on AZ91 Mg alloy using a Confined Field Unbalanced Magnetron Sputtering (CFUBMS) system to increase fatigue and tensile strength. The structural properties of the films were analyzed by using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometry (EDS) methods, and the mechanical properties were analyzed by rotating bending fatigue and tensile testing machines. Ti+TiN+Ti+TiVN multilayer nitride surface coatings on AZ91 Mg alloys showed a dense and columnar microstructure and according to XRD results (111) was the preferred orientation with the dominant peak. The fatigue limit value of the AZ91 base material was fixed at 60.46 MPa, while it increased to 68.48 MPa after being coated with multilayer nitride. Along with the multilayer nitride coating, the tensile strength increased from 169.98 MPa to 175.43 MPa. As a result, the multilayer hard nitride coating with low surface roughness, which fills the defects, notches, and voids on the surface of the AZ91 base material, increased the fatigue and tensile strength in parallel. Based on the outcomes of the research, the literature has been enriched with an innovative approach through the enhancement of fatigue and tensile strengths by applying a CFUBMS coating to lightweight metals and alloys, such as AZ91, especially in the transportation industry where lightness and dynamic load resistance are essential.
- MakaleAçık Erişim2023Green synthesis of fluorescent carbon dots from Robinia hispida L. leaves for selective detection of Hg (II)
Başoğlu, Aysel
In this study, Robinia hispida L leaves (RH) was used as a precursor for the first time to synthesize fluorescent carbon dots (CDs) with stable blue fluorescence by a single-step hydrothermal synthesis method. Notably, the innovative approach eliminates the necessity for toxic chemicals or hazardous substances, marking a significant advancement in the field. The synthesized CDs demonstrate CDs demonstrates the predominance of spherical shapes with an average size of 11.63 ± 1.92 nm. The CDs not only exhibit an enhanced fluorescent efficiency with a relatively high quantum yield of up to 6.8%, but they also possess the potential for direct utilization in the selective determination of Hg(II) through fluorescence quenching, even without any functionalization. Under the optimized conditions at a pH of 7.0, a robust linear correlation was found to exist between the fluorescence intensity and the concentration of Hg (II) within the range of 5–17.5 μM, exhibiting a detection limit (3σ) of 1.5 μM. Additionally, this methodology was effectively employed to successfully detect Hg (II) ions in various aqueous samples, including tap water, spring water, drinking water, and a certified reference material (CRM-SA-C Sandy Soil C). The spike recoveries of 97.6%–101.6% with less than 2.7% variability were performed on all samples.
- MakaleAçık Erişim2023The effect of the surface morphology of the aluminium oxide layer on the physical and bacterial attachment behavior
Kaya, Şevval; Sarıbıyık, Oğuz Yunus
Coating of the metal surface for different fields such as corrosion resistance, hydrophobic surface, and conductivity properties enhance the material quality for different application. Furthermore, controlling the morphological structures and the size of the coating materials is one of the most important factors for designing their functionality. The new approaches to the effect of surface properties at the atomic level on bacterial adhesion offer new perspectives on this subject. In this study, the effect of the different current densities on the morphological microstructural features, microhardness properties, and bacterial attachment behavior of the protective aluminum oxide layer was investigated by using different analytical and instrumental methods. The Staphylococcus aureus was used as a model bacteria for attachment tests. The result presented in the current study exhibited that the crystal morphology, microhardness, and bacterial adhesion features have changed depending on the applied current density. Increasing the current density from 1.5 to 1.7 raises the microhardness from 88 to 126 (Vickers) and causes higher surface roughness by 56 nm, 114 nm and 124 nm respectively. The high number of the attached bacteria were determined on the more roughness surface during the study.
- MakaleAçık Erişim2023Excited muon production in muon colliders via contact interaction
Sahin, M.; Caliskan, A.
In recent years, with the enlightenment of some issues encountered in muon colliders, muon colliders have become more feasible for the high-energy physics community. For this reason, we studied the single production of an excited muon in muon colliders via contact interactions. In addition, we assumed that the excited muon decayed into a photon and muon through gauge interactions. Then, signal and background analyses were performed in muon-antimuon collider options with center-of-mass energies of 6, 14, and 100 TeV. The attainable mass and compositeness scale limits were calculated for the excited muon in these collider options. Based on the calculations, it was concluded that muon-antimuon colliders would be a perfect collider option for excited muon investigations.
- DergiMethods and Applications in Fluorescence
- DergiMaterials Research Express
- DergiPhysica Scripta
- DergiSurface Topography: Metrology and Properties