A rapid and direct method for half value layer calculations for nuclear safety studies using MCNPX Monte Carlo code

Tekin H.O.,ALMisned Ghada,Issa Shams A.M.,Zakaly Hesham M.H. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.9

Half Value Layer calculations theoretically need prior specification of linear attenuation calculations, since the HVL value is derived by dividing ln(2) by the linear attenuation coefficient. The purpose of this study was to establish a direct computational model for determining HVL, a vital parameter in nuclear radiation safety studies and shielding material design. Accordingly, a typical gamma-ray transmission setup has been modeled using MCNPX (version 2.4.0) general-purpose Monte Carlo code. The MCNPX code's INPUT file was designed with two detection locations for primary and secondary gamma-rays, as well as attenuator material between those detectors. Next, Half Value Layer values of some well-known gamma-ray shielding materials such as lead and ordinary concrete have been calculated throughout a broad gamma-ray energy range. The outcomes were then compared to data from the National Institute of Standards and Technology. The Half Value Layer values obtained from MCNPX were reported to be highly compatible with the HVL values obtained from the NIST standard database. Our results indicate that the developed INPUT file may be utilized for direct computations of Half Value Layer values for nuclear safety assessments as well as medical radiation applications. In conclusion, advanced simulation methods such as the Monte Carlo code are very powerful and useful instruments that should be considered for daily radiation safety measures. The modeled MCNPX input file will be provided to the scientific community upon reasonable request.

Enhancement of nuclear radiation shielding and mechanical properties of YBiBO₃ glasses using La₂O₃

Issa, Shams A.M.,Ali, Atif Mossad,Tekin, H.O.,Saddeek, Y.B.,Al-Hajry, Ali,Algarni, Hamed,Susoy, G. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6

In this study, nuclear radiation shielding and rigidity parameters of Y (0.1-x)B0.6Bi1.8O3La2x glassy system were investigated in order to determine it's suitability for use as nuclear radiation shielding materials. Therefore, a group of bismuth borate glass samples with La₂O₃ additive were synthesized using the technique of melt quenching. According to the results, the increase of the La₂O₃ additive increases the density of the glass samples and the mass attenuation coefficient (μ_m) values, whereas the half-value layer (HVL) and mean free path (MFP) values decrease. The effective atomic number (Z_eff) is also enhanced with an increment of both mass removal cross section for neutron (Σ_R) and absorption neutron scattering cross section (σ_abs). In addition to the other parameters, rigidity parameter values were theoretically examined. The increase of La₂O₃ causes some other important magnitudes to increase. These are the average crosslink density, the number of bonds per unit volume, as well as the stretching force constant values of these glass samples. These results are in concordance with the increase of elastic moduli in terms of the Makishima-Mackenzie model. This model showed an increase in the rigidity of the glass samples as a function of La₂O₃.

Investigations of radiation shielding using Monte Carlo method and elastic properties of PbO-SiO2-B2O3-Na2O glasses

Shams A.M. Issa,Yasser B. Saddeek,H.O. Tekin,M.I. Sayyed,Khamies saber Shaaban 한국물리학회 2018 Current Applied Physics Vol.18 No.6

Several physical parameters such as the packing density (PD), oxygen molar volume (OMV), oxygen packing density (OPD) and the elastic moduli of the quaternary glass system xPbO-(30-x)SiO2-46.67B2O3-23.33Na2O (x = 0, 5, 10 and 15 mol%) have been evaluated. The elastic moduli were computed according to Makishima-Mackenzie model and Rocherulle model. The values of these moduli have been compared to their experimental values. Moreover, different shielding parameters such as mass attenuation coefficients (MAC), half value layer (HVL), mean free path (MFP), effective atomic numbers (EAN), effective electron densities (EED) and buildup factors have been evaluated using the WinXcom program in the energy range 0.015–15 MeV for the quaternary studied glass system. The MAC values have been compared with MCNPX (version 2.6.0) Monte Carlo code. Besides, mass stopping power (MSP) for proton, alpha and electron as well as the removal cross section for fast neutron (∑R) have been calculated. The results observed that the composition has the highest value of PbO (15 mol %) showed excellent nuclear radiation shielding and elastic properties.

An extensive investigation on gamma ray shielding features of Pd/Ag-based alloys

O. Agar,M.I. Sayyed,F. Akman,H.O. Tekin,M.R. Kaçal 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.3

A comprehensive study of photon interaction features has been made for some alloys containing Pd andAg content to evaluate its possible use as alternative gamma radiations shielding material. The massattenuation coefficient (m/r) of the present alloys was measured at various photon energies between81 keVe1333 keV utilizing HPGe detector. The measured m/r values were compared to those of theoreticaland computational (MCNPX code) results. The results exhibited that the m/r values of the studiedalloys are in the same line with results of WinXCOM software and MCNPX code results at all energies. Moreover, Pd75/Ag25 alloy sample has the maximum radiation protection efficiency (about 53% at81 keV) and lowest half value layer, which shows that Pd75/Ag25 has superior gamma radiationshielding performance among the other compared alloys.

Physical and nuclear shielding properties of newly synthesized magnesium oxide and zinc oxide nanoparticles

Rashad, M.,Tekin, H.O.,Zakaly, Hesham MH.,Pyshkina, Mariia,Issa, Shams A.M.,Susoy, G. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.9

Magnesium oxide (MgO) and Zinc oxide (ZnO) nanoparticles (NPs) have been successfully synthesized by solid-solid reaction method. The structural properties of ZnO and MgO NPs were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicated a formation of pure MgO and ZnO NPs. The mean diameter values of the agglomerated particles were around to be 70 and 50 nm for MgO and ZnO NPs, respectively using SEM analysis. Further, a wide-range of nuclear radiation shielding investigation for gamma-ray and fast neutrons have been studied for Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. FLUKA and Microshield codes have been employed for the determination of mass attenuation coefficients (μ_m) and transmission factors (TF) of Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. The calculated values for mass attenuation coefficients (μ_m) were utilized to determine other vital shielding properties against gamma-ray radiation. Moreover, the results showed that Zinc oxide (ZnO) nanoparticles with the lowest diameter value as 50 nm had a satisfactory capacity in nuclear radiation shielding.

Investigations on borate glasses within SBC-Bx system for gamma-ray shielding applications

Rammah, Y.S.,Tekin, H.O.,Sriwunkum, C.,Olarinoye, I.,Alalawi, Amani,Al-Buriahi, M.S.,Nutaro, T.,Tonguc, Baris T. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.1

This paper examines gamma-ray shielding properties of SBC-Bx glass system with the chemical composition of 40SiO₂-10B₂O₃-xBaO-(45-x)CaO- yZnO- zMgO (where x = 0, 10, 20, 30, and 35 mol% and y = z = 6 mol%). Mass attenuation coefficient (µ/ρ) which is an essential parameter to study gamma-ray shielding properties was obtained in the photon energy range of 0.015-15 MeV using PHITS Monte Carlo code for the proposed glasses. The obtained results were compared with those calculated by WinXCOM program. Both the values of PHITS code and WinXCOM program were observed in very good agreement. The (µ/ρ values were then used to derive mean free path (MFP), electron density (N_eff), effective atomic number (Z_eff), and half value layer (HVL) for all the glasses involved. Additionally, G-P method was employed to estimate exposure buildup factor (EBF) for each glass in the energy range of 0.015-15 MeV up to penetration depths of 40 mfp. The results reveal that gamma-ray shielding effectiveness of the SBC-Bx glasses evolves with increasing BaO content in the glass sample. Such that SBC-B35 glass has superior shielding capacity against gamma-rays among the studied glasses. Gamma-ray shielding properties of SBC-B35 glass were compared with different conventional shielding materials, commercial glasses, and newly developed HMO glasse. Therefore, the investigated glasses have potential uses in gamma shielding applications.

Neutron-shielding behaviour investigations of some clay-materials

S.F. Olukotun,Kulwinder Singh Mann,S.T. Gbenu,F.I. Ibitoye,O.F. Oladejo,Amit Joshi,H.O. Tekin,M.I. Sayyed,M.K. Fasasi,F.A. Balogun,Turgay Korkut 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.5

The fast-neutron shielding behaviour (FNSB) of two clay-materials (Ball clay and Kaolin)of SouthwesternNigeria (7.49 N, 4.55 E) have been investigated using effective removal cross section, SRðcm 1Þ, massremoval cross section, SR=rðcm2g 1Þ and Mean free path, l (cm). These parameters decide neutronshielding behaviour of any material. A computer program - WinNC-Toolkit has been used for computationof these parameters. The toolkit evaluates these parameters by using elemental compositions anddensities of samples. The proficiency of WinNC-Toolkit code was probe by using MCNPX and GEANT4 tomodel fast neutron transmission of the samples under narrow beam geometry, intending to representthe actual experimental setup. Direct calculation of effective removal cross section (cm 1) of the sampleswas also carried out. The results from each of the methods for each types of the studied clay-materials(Ball clay and Kaolin) shows similar trend. The trend might be the fingerprint of water content retainedin each of the samples being baked at different temperature. The compositions of each sample have beenobtained by Particle-Induced X-ray Emission (PIXE) technique (Tandem Pelletron Accelerator: 1.7 MV,Model 5SDH). The FNSB of the selected clay-materials have been compared with standard concrete. Thecognizance of various factors such as availability, thermo-chemical stability and water retaining ability bythe clay-samples can be analyzed for efficacy of the material for their FNSB.

Exploring critical behavioral differences in physical, structural, and nuclear radiation attenuation properties of produced High Entropy Alloy (HEA) and Refractory-High Entropy Alloy (RHEA) samples

Güler Seval Hale,Güler Ömer,Kavaz E.,Almisned Ghada,Issa Bashar,Tekin H.O. 한국물리학회 2024 Current Applied Physics Vol.58 No.-

Refractory-High entropy alloys (RHEAs) are known for their exceptional mechanical and radiation-resistant properties, making them promising materials for use in nuclear reactors. Their high entropy composition, which consists of multiple elements in roughly equal proportions, can create a stable microstructure that withstands high levels of radiation damage. The objective of this work is to further our comprehension of the unique behavioral, physical, structural, and nuclear radiation attenuation characteristics shown by High-Entropy Alloys (HEA) and Refractory-High entropy alloy (RHEA) materials. Accordingly, two high entropy alloy (HEA) samples through two different compositions were produced. The first composition under consideration is the typical high-entropy alloy (HEA) defined as MnCrFeNiCoMo0.5. The second composition under consideration is a refractory high entropy alloy (RHEA) characterized by the following elemental composition: TiZrNbHfVTa0.1. SEM and EDX analyses were conducted in terms of determining their physical and structural attributes. Next, a133Ba radioisotope together with a HPGe detector were utilized for gamma-ray transmission experiments. Finally, a241Am/Be source and a gas proportional detector were used for neutron absorption experiments for HEA and RHEA samples. The alloy structures displayed a unique degree of uniformity. Throughout the RHEA phase, the incorporation of refractory elements did not provide any discernible adverse impacts on the physical stability. The counting spectrum provided a clear explanation of the gamma ray absorption features shown by the RHEA (R) sample, highlighting its exceptional absorption properties. Regarding the absorption properties of neutrons, it was observed that RHEA had a comparatively reduced amount of absorption. Therefore, it can be concluded that the basic structure of RHEA grants it superior gamma-ray attenuation qualities compared to HEA. It can be concluded that RHEA demonstrates superior applicability as a material in comparison to HEA, especially in situations involving the use of fuel rods, where maintaining of neutron quantity has paramount importance for achieving optimum neutron activation.

Towards a better understanding of detection properties of different types of plastic scintillator crystals using physical detector and MCNPX code

Yilmaz Ayberk,Alan Hatice Yilmaz,Susam Lidya Amon,Akkus Baki,ALMisned Ghada,Ilhan Taha Batuhan,Tekin H.O. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.12

The purpose of this comprehensive research is to observe the impact of scintillator crystal type on entire detection process. For this aim, MCNPX (version 2.6.0) is used for designing of a physical plastic scintillation detector available in our laboratory. The modelled detector structure is validated using previous studies in the literature. Next, different types of plastic scintillation crystals were assessed in the same geometry. Several fundamental detector properties are determined for six different plastic scintillation crystals. Additionally, the deposited energy quantities were computed using the MCNPX code. Although six scintillation crystals have comparable compositions, the findings clearly indicate that the crystal composed of PVT 80% þ PPO 20% has superior counting and detecting characteristics when compared to the other crystals investigated. Moreover, it is observed that the highest deposited energy amount, which is a result of the highest collision number in the crystal volume, corresponds to a PVT 80% þ PPO 20% crystal. Despite the fact that plastic detector crystals have similar chemical structures, this study found that performing advanced Monte Carlo simulations on the detection discrepancies within the structures can aid in the development of the most effective spectroscopy procedures by ensuring maximum efficiency prior to and during use.