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- MakaleYalnız künye2026Radiation 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.
- MakaleYalnız künye2026Computational 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.