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• MakaleYalnız künye2026/r/gumushane/10229
  Computational gamma-ray attenuation and fast-neutron removal cross-section assessment of CrN, AlCrN and AlTiCrN ceramic coatings using EGS4 Monte Carlo and Phy-X/PSD

  Sirin, Murat; Kaya, Selim; Aktarer, Semih Mahmut; Baltas, Hasan; Küçükömeroglu, Tevfik

  In this study, the computationally predicted gamma-ray attenuation behavior and fast-neutron removal cross-section characteristics of micrometre-scale CrN, AlCrN, and AlTiCrN ceramic coatings produced via cathodic arc evaporation were investigated. The shielding parameters were not measured by direct gammaor neutron-transmission experiments; instead, mass attenuation coefficients (MAC, mu/rho) in the 0.05-2.50 MeV range were obtained from EGS4 Monte Carlo simulations and Phy-X/PSD calculations, and the agreement between the two computational datasets was evaluated. Energy-dependent attenuation parameters, including half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), radiation protection efficiency (RPE), and kerma coefficients, were calculated. Statistical comparison showed good consistency between EGS4 and Phy-X/PSD for MAC, RPE, HVL, MFP, and kerma coefficients, whereas Zeff exhibited larger method-dependent deviations. All coatings showed higher attenuation at low photon energies due to the photoelectric effect, while Compton scattering dominated at intermediate energies. Among the investigated coatings, CrN exhibited the most favorable calculated gamma-ray attenuation indicators, with lower HVL and MFP values and higher RPE values. The macroscopic fast-neutron removal cross-section (Sigma R) was also calculated as a first-order neutron attenuation indicator, and CrN showed the highest Sigma R value. Considering their limited thickness of approximately 2.3-2.8 mu m, these coatings should not be regarded as replacements for conventional bulk radiation shields. Instead, nitride-based ceramic coatings may serve as secondary or multifunctional surface layers in space-restricted components requiring local radiation attenuation and mechanical durability.

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• MakaleAçık Erişim2026/r/gumushane/10627
  Long-term decline of Chernobyl-derived 137Cs in mosses and lichens from the Eastern Black Sea region of Türkiye

  Çevik, Ugur; Çelik, Necati; Uzun, Kubra K.; Çelik, Ahmet; Koz, Bahadir; Özen, Songul A.; Yesilkanat, Cafer M.; Hacisalihoglu, Aylin; Özkalayci, Fatih; Kaya, Selim

  This study presents the third consecutive assessment of 13 Cs activity concentrations in the same 50 moss (7 species) and lichen (2 species) sampling points in Ordu province, T & uuml;rkiye, one of the most heavily contaminated areas following the Chernobyl accident. Samples were collected from exactly the same locations used in the 1997 and 2007 studies and analyzed by high-resolution gamma spectrometry. In 2025, detectable 13 Cs was found in 14 of 30 moss sites (47%) and 3 of 20 lichen sites (15%). For samples below the minimum detectable activity (MDA), a value of MDA/2 (0.93 Bq kg-1) was substituted for lichens, while moss samples below the MDA were excluded from regression. The ecological half-life (Teco) for the 2007-2025 period was 4.38 +/- 1.05 years for mosses and 4.18 +/- 0.61 years for lichens. For mosses, this is nearly identical to the 1997-2007 mean (4.4 years), while for lichens it decreased from 5.6 to 4.18 years, suggesting a slight acceleration in environmental removal. All Teco values remain far shorter than the physical half-life of 13 Cs (30 years), confirming that environmental removal processes dominate over radioactive decay. Residual 13 Cs is concentrated in higher-altitude areas, reflecting the original deposition pattern and slower removal in cooler, more humid microenvironments. Nearly 39 years after the accident, the radiological risk posed by residual trace levels is negligible. This 28-year dataset provides one of the longest continuous records of 13 Cs in epiphytic bioindicators and serves as a valuable baseline for future contamination events.

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• MakaleYalnız künye2026/r/gumushane/14223
  Optimizing compton suppression systems: A parametric monte carlo study of NaI scintillator geometry

  Kaya, Ali; Çelik, Necati; Kaya, Selim

  Compton suppression systems are widely used to enhance gamma-ray spectral quality in applications such as nuclear safeguards and environmental radioactivity measurements. Although optimization of high-purity germanium (HPGe) detectors has been extensively reported, the geometric optimization of secondary sodium iodide [NaI(Tl)] scintillation detectors remains less studied. This work investigates the influence of annular and plug NaI(Tl) detector geometry—length, thickness, and radius—on Compton suppression performance using Monte Carlo simulations. Performance is evaluated in terms of the peak Compton suppression factor (CSFpeak) and total Compton suppression factor (CSFtotal). The results show that CSFpeak and CSFtotal increase with plug length (2–10.2 cm) and annular thickness (1–5.85 cm), with saturation observed beyond approximately 8–10 cm and 4–5 cm, respectively, due to reduced incremental photon absorption. The plug detector radius (3.72–5.1 cm) exhibits a nonlinear effect, with optimal performance achieved at 4.55–4.83 cm, beyond which gains are marginal (<5%). Suboptimal geometries (plug length <6 cm, annular thickness <3 cm, plug radius <4.28 cm) result in 20–60% lower suppression performance, increasing Compton continuum contributions in 662 keV spectra. The optimal configuration—plug length of 8–10 cm, plug radius of 4.55–4.83 cm, and annular thickness of 4–5 cm—achieves more than 90% of maximum CSFpeak and CSFtotal while maintaining a balance between performance and detector volume. These results provide quantitative design guidelines for optimizing NaI(Tl)-based Compton suppression systems for improved gamma-ray spectrometry performance.

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• MakaleAçık Erişim2026/r/gumushane/14195
  La2O3 addition's effect on sodium-barium borosilicate glasses' radiation shielding capability: WinXCOM and EGS4 Monte Carlo analysis

  Kaya, Selim

  This study thoroughly investigated the impact of La2O₃ inclusion on the radiation shielding effectiveness of sodium-barium borosilicate glasses using EGS4 Monte Carlo simulations and WinXCOM computations. The gamma-ray shielding behavior of a set of glass samples was systematically investigated over a wide photon energy interval ranging from 50 to 2506 keV. The glass compositions were modified through the stepwise substitution of Na₂O with La₂O₃. Key radiation interaction and shielding metrics—including the mass attenuation coefficient (μ/ρ), half-value layer (HVL), mean free path (MFP), radiation protection efficiency (RPE), effective atomic number (Zeff), and kerma coefficients—were determined and comparatively evaluated. The results demonstrate that the progressive incorporation of La₂O₃ leads to a marked enhancement in radiation shielding performance, particularly within the low-and intermediate-photon energy ranges where photoelectric interactions prevail. The inclusion of La₂O₃ results in increased material density, μ/ρ, Zeff, and kerma values, while simultaneously reducing (HVL) and MFP.In conclusion, sodium-barium borosilicate glasses treated with La₂O₃ have better radiation attenuation capacities than their La₂O₃-free counterparts. These results validate the effectiveness of La₂O₃ substitution as an approach for customizing borosilicate glass systems for applications that need improved radiation shielding.

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• MakaleYalnız künye2026/r/gumushane/13791
  Influence of holmium substitution on structural characteristics and radiation shielding parameters of YBCO (358) superconducting ceramics

  Düzgün, İbrahim; Kaya, Selim; Gül, Osman

  This study reports on the structural characterization, radiation shielding assessment, and magnetic-field response of holmium-substituted Y3-xHoxBa5Cu8O18+δ superconducting ceramics synthesized by the conventional solid-state reaction route. X-ray diffraction measurements on five compositions (x = 0, 0.75, 1.5, 2.25, 3) supported the formation of a dominant orthorhombic Y358-type matrix across the substitution range. Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) revealed a progressive microstructural evolution with increasing Ho content, including SEM–BEC/EDS-detectable Ho-rich inclusions consistent with Ho2BaCuO5-type secondary particles at higher substitution levels. XCOM-based mass attenuation coefficients, half-value layer, mean free path, effective atomic number, radiation protection efficiency, gamma-ray kerma coefficients, and fast-neutron removal cross-sections were calculated for all five compositions over 50–2000 keV. EGS4 Monte Carlo simulations independently verified the XCOM results for three representative compositions (x = 0, 1.5, and 3). Ho-containing specimens exhibited a significant enhancement in photon absorption near 60 keV, associated with the increased photoelectric contribution of holmium in the vicinity of its K-absorption edge. Among the full five-composition series, the x = 2.25 specimen (ρ = 5.531 g cm−3) exhibited the best calculated shielding performance across the full energy range, owing to its highest bulk density combined with substantial Ho incorporation. The x = 1.5 specimen provided the most balanced calculated radiation-attenuation and hysteretic magnetic response among the three representative compositions examined by EGS4 and M–H measurements at 20 K, retaining approximately 93% of the reference M–H hysteresis area while full substitution reduces it by roughly 67%. These findings establish a multi-parametric reference dataset for Ho-substituted Y358 ceramics and demonstrate the promise of rare-earth-engineered superconducting ceramics as multifunctional materials in radiation-intensive environments.

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• MakaleAçık Erişim2026/r/gumushane/13588
  Enhancing precision of low-cost detectors via machine learning for accurate mass attenuation coefficient estimation

  Düzgün, İ.; Küçük, M.A.; Kaya, S.; Çelik, N.

  Low-cost NaI(Tl) detectors are practical for gamma-ray spectrometry but their limited energy resolution can introduce systematic errors in mass attenuation coefficient measurements when scattered photons are included in the peak region. This study proposes a machine-learning correction framework that maps NaI(Tl)-derived attenuation coefficients to XCOM-based HPGe-equivalent reference values through a dimensionless correction factor. An EGS4/XCOM dataset of 756 model-development configurations, covering 18 atomic numbers, six monoenergetic photon energies, and seven collimator radii, was used to train twelve regression models and evaluate them over 60 randomized train–validation–test cycles. Sodium and Bismuth were withheld for external material-wise validation. Gaussian Process Regression with a Matérn 5/2 kernel provided the best overall testing performance. For the withheld materials, the correction reduced the mean deviation from XCOM references from 3.07% to 0.83%, supporting its use as a practical correction layer for low-cost attenuation measurements.

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• MakaleAçık Erişim2026/r/gumushane/13581
  Computational 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.

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• MakaleYalnız künye2026/r/gumushane/13558
  Influence 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).

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• MakaleYalnız künye2026/r/gumushane/13515
  Radiation shielding performance and microstructural characterization of Al–Cu-Sc/B4C nanocomposites

  Şirin, Murat; Kaya, Selim; Temiz, Cengiz; Çağlar, Seyit

  This study investigates the gamma-ray and fast-neutron shielding performance of Al–Cu–Sc/B4C nanocomposites containing 0–20 wt% boron carbide (B4C). The composites were produced using melt spinning, high-energy ball milling, and vacuum sintering techniques. Their structural and microstructural characteristics were examined by X-ray diffraction and scanning electron microscopy. Gamma-ray attenuation properties were measured experimentally at photon energies of 0.662, 1.173, and 1.333 MeV using a high-purity germanium detector. In addition, theoretical calculations were carried out in the 0.05–2.50 MeV energy range using Monte Carlo simulations together with the Phy-X/PSD calculation platform. Several radiation shielding parameters were evaluated, including the mass attenuation coefficient, half-value layer, mean free path, radiation protection efficiency, effective atomic number, and fast-neutron removal cross-section. The results show that the incorporation of B4C improves the fast-neutron shielding capability of the composites. The sample containing 20 wt% B4C exhibits an increase of approximately 32% in fast-neutron removal cross-section compared with the reference alloy. A slight reduction in gamma-ray attenuation is observed at low photon energy, whereas the shielding performance at medium and high energies remains nearly unchanged. These findings indicate that Al–Cu–Sc/B4C nanocomposites are promising lightweight and lead-free candidates for shielding against mixed gamma and neutron radiation. Their low density and the absence of toxic lead support potential applications in medical radiation facilities, nuclear technology systems, aerospace platforms, and industrial radiation environments where both radiation protection and weight reduction are important.

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• MakaleYalnız künye2026/r/gumushane/12195
  Assessment of gamma-ray attenuation properties in advanced ceramics incorporating colemanite, pyrophyllite, and plastic clay

  Uysal, Turan; Kaya, Selim

  This study investigates the gamma-ray and neutron shielding performance of advanced ceramic composites containing colemanite, pyrophyllite, and plastic clay as environmentally friendly alternatives to conventional lead-based shielding materials. Gamma-ray attenuation properties were evaluated over the energy range of 59.54–2000 keV using theoretical calculations from WinXCOM and Monte Carlo simulations performed with the EGS4 code. Excellent agreement between the two methods confirmed the reliability of the simulation results. The mass attenuation coefficient (μ/ρ) decreased with increasing photon energy due to the transition from photoelectric absorption to Compton scattering and pair production mechanisms. Correspondingly, the half-value layer (HVL) and mean free path (MFP) increased, while radiation protection efficiency (RPE) decreased with photon energy. The effective atomic number (Zeff) exhibited an energy-dependent decline, reflecting changes in dominant photon–matter interaction processes. Neutron shielding performance improved with increasing colemanite content owing to the presence of boron-rich phases, and Sample-5 exhibited the highest fast neutron removal cross-section (ΣR = 0.11062 cm−1). The same sample also showed the highest gamma-ray kerma coefficients, indicating enhanced energy absorption capability. Overall, the results demonstrate that colemanite-enriched ceramic composites provide effective combined gamma-ray and neutron shielding and represent promising, sustainable, and non-toxic alternatives for radiation protection applications.

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