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γ-ray, fast and thermal neutrons shielding features for five Pb-free {[(TeO 2) 0.70 (B 2 O 3) 0.30 0.7 (ZnO) 0.30 } (1- x) (La 2 O 3) x (x = 0.01, 0.02, 0.03, 0.04, and 0.05 mol%) glasses have been inspected in this work. For all samples, within the photon energy range of 0.015–15 MeV, linear attenuation coefficients (μ) and mass attenuation coefficients (μ/ρ) were estimated using WinXCOM program (theoretical approach), and obtained μ/ρ values are in fine agreement with computed μ/ρ results of respective MCNP5, Geant4, and Penelope codes. By utilizing μ/ρ values of WinXCOM, γ -ray attenuation parameters like effective atomic number (Z eff), effective electron density (N eff), half-value layer (HVL), and mean free path (MFP) were assessed within 0.015–15 MeV photon energy range, for all samples. Additionally, exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) were calculated for all samples by applying a five parameter geometric progression (G‒P) fitting method as a function of various penetration depths (1, 5, 10, 15, 20, 25, 30, 35, and 40 mfp) within 0.015–15 MeV photon energy range. The derived radiation protection efficiency (RPE) results indicate all samples' effective attenuation competence for lower energy γ -rays. Among all glasses, 46.55TeO 2 -19.95B 2 O 3 -28.5ZnO–5La 2 O 3 (mol%) sample, by having relatively bigger μ/ρ and Z eff , minimal HVL and MFP, and lowest EBF and EABF, endorse its' excellent γ -ray shielding effectiveness. Further, neutron shielding parameters such as macroscopic removal cross-section for fast neutrons (Σ R), coherent and incoherent scattering cross-sections (σ cs & σ ics), absorption cross-section (σ A), and total cross-section (σ T) for thermal neutrons were explored. By using the Geant4 code, ' σ T ' values have been deduced within 10−4‒10−8 MeV neutron energy range. The 46.55TeO 2 -19.95B 2 O 3 -28.5ZnO–5La 2 O 3 (mol%) glass owns relatively larger Σ R (0.1474 cm−1) for fast neutrons attenuation and ' σ T ' (10.1444 cm−1 at 0.0253 eV neutron energy, 15.9824 cm−1 → 0.551 cm−1 from 1 × 10−8 MeV →1 × 10−4 MeV neutron energy) for thermal neutrons absorption, respectively, revealing its' superior neutrons shielding ability. [ABSTRACT FROM AUTHOR]

This paper focuses on the effect of Bi 2 O 3 content (up to 80 mol%) on mechanical features and radiation shielding characteristics of boro-tellurite glasses within TeO 2 –B 2 O 3 –Bi 2 O 3 system. The basic mechanical parameters such as oxygen molar volume, packing density, hardness, and elastic moduli were studied based on Makishima–Mackenzie's theory. The shielding studies of the TeO 2 –B 2 O 3 –Bi 2 O 3 glasses included gamma, electron and neutron radiations. The newly developed Phy-X/PSD program and Geant4 simulation were used to calculate the shielding parameters such as mass attenuation coefficient (μ/ρ), tenth value layer (TVL), mean free path (MFP), stopping power (ψ e)), removal cross section (RCS), CSDA range, effective atomic number (Z eff), and half value layer (HVL). The concentration of Bi 2 O 3 content had a significant effect on the gamma shielding competence of the investigated glasses. Form the results of gamma shielding studies, the highest μ/ρ (99.845 cm2/g) occurred at 0.015 MeV for TBB80 and the lowest μ/ρ (0.039 m2/g) occurred at 4 MeV for TBB40. The maximum values of Z eff for gamma interaction occurred at 0.02 MeV and they were 77.26, 78.81, 79.94, 80.80, and 81.48 for TBB40, TBB50, TBB50, TBB60, TBB70, and TBB80, respectively. The gamma shielding features of the investigated glasses were compared with those of various ordinary concretes, and Pb-free, Pb-based, and commercial glasses. The Bi 2 O 3 content had also a considerable influence on the electron shielding competence of the tested glasses. The maximum values of Z eff for electron interaction occurred at 14 MeV and they were 44.58, 47.72, 50.41, 52.75, and 53.73 for TBB40, TBB50, TBB50, TBB60, TBB70, and TBB80, respectively. The results revealed that the bismuth boro-tellurite glasses could be useful for the shielding against gamma, electron, and neutron radiations, wherein the Bi 2 O 3 content can be balanced according to the type and energy of radiation. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the mechanical features and radiation shielding properties of (100–2x)TeO 2 +xAg2O + xWO 3 (where x = 7.5, 15, 22.5, and 30 mol%) glass system. Based on Makishima–Mackenzie's theory, the basic mechanical features such as packing density, Poisson's ratio, elastic moduli, hardness, and fractal bond connectivity were studied. The shielding investigations included the radiations of gamma, electron, neutron, and heavy charged particles. Geant4 toolkit and newly developed Phy-X program were employed to evaluate mass attenuation coefficient (μ/ρ), transmission factors (HVL and MFP), exposure buildup factor (EBF) and effective atomic number (Z eff) of gamma and charged particles for the studied glasses. Neutron shielding investigation was examined by determining neutron removal cross section (NRCS) of the glasses involved. The results showed that Ag 2 O and WO 3 contents had an insignificant effect on the mechanical properties of the investigated glass system. In contrast, the Ag 2 O and WO 3 contents had a significant effect on the shielding capacity of the glasses against gamma radiation and charged particles. The Z eff values were in the range of 24–60 for gamma, 24–31 for electron, 18–24 for proton, 15–23 for alpha, and 13–19 for carbon ion. The shielding properties of these glasses were compared with those of commonly used shields. The investigated glass system can be used in shielding applications, wherein Ag 2 O and WO 3 contents can be balanced with the TeO 2 content according to the type and energy of the radiation. [ABSTRACT FROM AUTHOR]

A new bioactive glass system with the structure of P 2 O 5 -Na 2 O-CaO-K 2 O-MgO (PNCKM) was prepared and assessed for use in radiation shielding applications. X-ray diffraction (XRD) and scanning electron microscope measurements were achieved for the prepared glasses. Gamma radiation shielding parameters such as mass attenuation coefficient (μ/ρ), effective atomic number (Z eff), and mean free path (MFP) were investigated by using Geant4 toolkit at nuclear medicine energies namely; 0.083 MeV emitted from 201Tl, 0.140 MeV emitted from 99Tc, and 0.284, 0.365, 0.637, and 0.723 MeV emitted from 131I. The obtained results are confirmed via the newly developed Phy-X/PSD program. At 0.365 MeV, the Z eff values were 10.31, 10.53, 10.76, 10.99, and 11.24 for PNCKM1, PNCKM2, PNCKM3, PNCKM4, and PNCKM5, respectively. The gamma shielding features of the PNCKM glasses were compared with those of commercial and conventional shielding materials in terms of half value layer (HVL). Moreover, neutron shielding features such as removal cross section (Σ R) were calculated for the prepared glasses and compared with those of standard bioactive glasses. The prepared glasses can be useful to design superior radiation shielding materials as well as to optimize the fabrication of low cost and environmentally friendly shields. [ABSTRACT FROM AUTHOR]

Gold nanoparticles are promising radiosensitizers for proton radiotherapy. However, the physical mechanisms of gold nanoparticles radiosensitization remain unclear. In the present study, the Geant4 toolkit was used to estimate by the Monte-Carlo simulation the changes (1) in the contribution of primary and secondary particles to the absorbed dose, (2) in the dose-averaged linear energy transfer, and (3) in the relative biological effectiveness of a 150 MeV proton beam caused by the addition of 50 mg/mL of gold nanoparticles to the irradiated water phantom. In the presence of gold nanoparticles no significant changes in the absorbed dose and the Bragg peak position were found, at the same time a redistribution of the contribution of secondary particles to the absorbed dose was recorded. An increase in the contributions from protons (~16%), recoil nuclei (~58%), α-particles (~400%), deuterons (~900%), tritons (~3000%), and photons (~7000%) was observed ~10 mm beyond the Bragg peak. The contribution of the secondary electrons decreased by ~35%. This redistribution led to ~5-fold increase in the dose-averaged linear energy transfer at the distal edge of the Bragg curve; this, in turn, may cause the ~1.4−2.2-fold increase in the relative biological effectiveness within this region. Thus, it is critically important to take into account the presence of gold nanoparticles when dosimetric planning proton radiotherapy in order to avoid unwanted damage to the normal tissues around the tumor. [ABSTRACT FROM AUTHOR]

Zinc-oxide powders consisting of spherical hollow particles are obtained by hydrothermal synthesis. Comparative analysis of the diffuse reflectance spectra and their changes after irradiation with 100-keV protons of powders of micrometer-sized hollow and bulk particles of zinc oxide is carried out. We present the results of the physical and mathematical simulation of the interaction of a low-energy proton beam with zinc-oxide particles, using the GEANT4 software package. The calculation results and the experimental data are compared. Hollow particles have a greater radiation resistance to protons compared to micrometer-sized bulk particles. The effect is determined by the absence of radiation-induced defects in the volume of spherical particles, a large ionization loss associated with surface-defect formation, and the significant relaxation of radiation-induced defects in a thin layer of spheres. [ABSTRACT FROM AUTHOR]

In this paper, the role of TeO 2 in radiation attenuating characteristics of xTeO 2 -10CaF 2 -(60–0.6x) B 2 O 3 -(30–0.4x) CaO glass system with x = 20, 25, 30, 35 and 40 wt% was investigated. The gamma radiation studies were carried out by utilizing Geant4 simulations and the newly developed Phy-X/PSD program. The gamma-shielding characteristics of the present glass samples were examined in terms of mass attenuation coefficient (μ/ρ), and some other related factors such as the effective atomic number (Z eff), and mean free path (MFP). The electron radiation-shielding characteristics were tested by determining the stopping power (ψ e) and CSDA range for each glass specimen. The neutron radiation-shielding characteristics were explored by evaluating the removal cross section (RCS) for the tested glasses. Moreover, the G-P method was employed to investigate the exposure buildup factor (EBF) for photon energies up to 15 MeV. The results showed that the TeO 2 content had a significant influence on the shielding ability of the investigated glasses against gamma and neutron radiations. In contrast, the TeO 2 content had an insignificant influence on the electron radiation-shielding capacity of the glasses involved. Additionally, the nuclear-shielding properties of the studied samples were compared with those of standard nuclear radiation shields. It can be concluded that the present calcium boro-tellurite glasses have a promising future to be used as a shielding material against gamma, electron and neutron radiation, wherein the TeO 2 concentration can be balanced according to the desired application. [ABSTRACT FROM AUTHOR]

Objective: First part of this work dedicated to the verification of the percentage depth dose curves that obtained experimentally for 6 MV and 18 MV x-ray photon beams via using Geant4 Monte Carlo simulation. Second part of this study compared the computed mass attenuation coefficients of various human tissues and water between MATLAB and XCOM. Material-Method: The central-axis percentage depth doses of Varian Clinac IX linear accelerator were verified via Monte Carlo simulation (Geant4) with square field sizes (10x10 and 30x30 cm²) for 6 MV and 18 MV x-ray photon energies. In addition, mass attenuation coefficients of adipose tissue, blood, muscle, bone, skin and water were computed with MATLAB and were compared with the NIST XCOM data. Results: Results of the Geant4 modeling were in line with the experimental measurements for percentage depth dose curves. The consistency of Geant4 with experimental results was more explicit for 6 MV photons with the field size of 10x10 cm². No statistically significant difference between MATLAB and XCOM were found for all mentioned human tissues, except for bone (p=0.039 for bone in both genders). The minimum median percentage differences were calculated for water and skin with a result of 1.23% and 2.19%, respectively. Conclusions: Geant4 can be used to predict percentage depth dose curves for medical linacs. Mass attenuation coefficients calculated with MATLAB yielded consistent results with previous studies, which means MATLAB can be used as an alternative simulation tool for estimating mass attenuation coefficients of various human tissues and water. [ABSTRACT FROM AUTHOR]

This work is devoted to determination of the response function of a BGO detector of γ-rays, which is used in experiments aimed at investigation of inelastic scattering of neutrons with energies of 14.1 MeV on various nuclei. A function is constructed to describe the Monte-Carlo simulated response of a gamma-detector, which allows taking into account all possible mechanisms of interaction of γ-rays with matter, as well as the geometric parameters of the detector. For all components of the function, an analytical form of their energy dependencies is selected and its parameters are determined in the case of registration of γ-quanta with energies in the range from 0.2 MeV to 8 MeV. [ABSTRACT FROM AUTHOR]

The transport of neutrons in long beamlines at spallation neutron sources presents a unique challenge for Monte-Carlo transport calculations. This is due to the need to accurately model the deep-penetration of high-energy neutrons through meters of thick dense shields close to the source and at the same time to model the transport of low- energy neutrons across distances up to around 150 m in length. Typically, such types of calculations may be carried out with MCNP-based codes or alternatively PHITS. However, in recent years there has been an increased interest in the suitability of Geant4 for such types of calculations. Therefore, we have implemented supermirror physics, a neutron chopper module and the duct-source variance reduction technique for low- energy neutron transport from the PHITS Monte-Carlo code into Geant4. In the current work, we present a series of benchmarks of these extensions with the PHITS software, which demonstrates the suitability of Geant4 for simulating long neutron beamlines at a spallation neutron source, such as the European Spallation Source, currently under construction in Lund, Sweden. [ABSTRACT FROM AUTHOR]

For 25 Li2O–(75 − x) B2O3–x Bi2O3 (where x = 0, 5, 10, 15, 20, 25, 30, 35, and 40 mol%) glasses, gamma-ray and neutrons attenuation features were explored by theoretical approach using ParShield/WinXCOM program, Geant4, and Penelope codes. At 133Ba (276, 303, 356, and 384 keV), 22Na (511 and 1280 keV), 137Cs (662 keV), 54Mn (835 keV), and 60Co (1170 and 1330 keV) photon peaks, for all samples, mass attenuation coefficient (μ/ρ), effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), and mean free path (MFP) parameters have been evaluated using ParShield/WinXCOM program. The μ/ρ values computed by WinXCOM, Geant4, and Penelope codes were compared to check the accuracy, and satisfactory agreement among the values was identified. Moreover, using G–P fitting method as a function of penetration depth (1, 5, 10, 15, 20, 25, 30, 35, and 40 mfp) within the photon energy range of 0.015–15 MeV, exposure buildup factor (EBF) and energy absorption buildup factor (EABF) were derived. For all selected glasses, the effectiveness of the neutrons attenuation has been discussed in terms of macroscopic effective removal cross-section (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total neutron cross-section (σT). The 'σT' values have been calculated within 10−4–10−8 MeV neutron energy range using the Geant4 code. The μ/ρ possessed larger values at the lowest energy and lower values at higher energy regions for all studied glasses. The μ/ρ, Zeff, HVL, and MFP values showed enhanced γ-ray shielding capability with Bi2O3 content increment in the samples. The 25 Li2O–35 B2O3–40 Bi2O3 (mol%) sample by having larger Zeq and/or Zeff value, faired lower EBF and EABF values. Largest μ/ρ and Zeff, and minimal HVL, MFP, EBF, and EABF values of 25 Li2O–35 B2O3–40 Bi2O3 (mol%) glass demonstrated its superior γ-ray attenuation ability among all examined glasses. Further, among all glasses, 25 Li2O–75 B2O3 (mol%) sample exhibits relatively higher ΣR (0.11326 cm−1) and 'σT' (46.109 cm−1 → 0.84607 cm−1 from 1 × 10−8 MeV → 1×10−4 MeV neutron energy) values for fast and thermal neutrons attenuation, respectively, indicating its better neutrons absorption competence. [ABSTRACT FROM AUTHOR]

Purpose: Minibeam radiation therapy (MBRT) is an innovative strategy based on a distinct dose delivery method that is administered using a series of narrow (submillimetric) parallel beams. To shed light on the biological effects of MBRT irradiation, we explored the micro‐ and nanodosimetric characteristics of three promising MBRT modalities (photon, electron, and proton) using Monte Carlo (MC) calculations. Methods: Irradiation with proton (100 MeV), electron (300 MeV), and photon (effective energy of 69 keV) minibeams were simulated using Geant4 MC code and the Geant4‐DNA extension, which allows the simulation of energy transfer points with nanometric accuracy. As the target of the simulations, cells containing spherical nuclei with or without a detailed description of the DNA (deoxyribonucleic acid) geometry were placed at different depths in peak and valley regions in a water phantom. The energy deposition and number of events in the cell nuclei were recorded in the microdosimetry study, and the number of DNA breaks and their complexity were determined in the nanodosimetric study, where a multi‐scale simulation approach was used for the latter. For DNA damage assessment, an adapted DBSCAN clustering algorithm was used. To compare the photon MBRT (xMBRT), electron MBRT (eMBRT), and proton MBRT (pMBRT) approaches, we considered the treatment of a brain tumor located at a depth of 75 mm. Results: Both mean energy deposition at micrometric scale and DNA damage in the "valley" cell nuclei were very low as compared with these parameters in the peak region at all depths for xMBRT and at depths of 0 to 30 mm and 0 to 50 mm for eMBRT and pMBRT, respectively. Only the charged minibeams were favorable for tumor control by producing similar effects in peak and valley cells after 70 mm. At the micrometer scale, the energy deposited per event pointed to a potential advantage of proton beams for tumor control, as more aggressive events could be expected at the end of their tracks. At the nanometer scale, all three MBRT modalities produced direct clustered DNA breaks, although the majority of damage (>93%) was composed of isolated single strand breaks. The pMBRT led to a significant increase in the proportion of clustered single strand breaks and double‐strand breaks at the end of its range as compared to the entrance (7% at 75 mm vs 3% at 10 mm) in contrast to eMBRT and xMBRT. In the latter cases, the proportions of complex breaks remained constant, irrespective of the depth and region (peak or valley). Conclusions: Enhanced normal tissue sparing can be expected with these three MBRT techniques. Among the three modalities, pMBRT offers an additional gain for radioresistant tumors, as it resulted in a higher number of complex DNA damage clusters in the tumor region. These results can aid understanding of the biological mechanisms of MBRT. [ABSTRACT FROM AUTHOR]

This research focused on an electron beam accelerator system for natural rubber vulcanization. In this accelerator, electrons are generated from a 17-keV DC gun and accelerated in a 5-cell RF linac with a resonant frequency of 2996.39 MHz and an effective length of 22.15 cm. The RF macro-pulse has a length of 4 μs with a maximum repetition rate of 200 Hz. Electron beam dynamics in the linac were studied using software ASTRA. It was found that the electron beam can be accelerated to have average kinetic energy in a range of 1–3.86 MeV for accelerating gradients of 16.2 to 39.5 MV/m. This accelerating range corresponds to the RF peak powers of 0.32–1.49 MW. The beam dynamic simulation results were used as the inputs for GEANT4 Monte Carlo simulation of electrons in the irradiation system. The beams exit the linac and collide with a 50-μm titanium window. Then, they travel through 18 cm of air and penetrate in the rubber latex with optimal depths of 0.3–1.3 cm for electron beam energies of 1–3.85 MeV. At the rubber surface, rectangular apertures with well-defined effective area were considered to select the beams with more uniform transverse distribution. The effective volumes defined from the optimum depth and the effective irradiation area are 0.01–6.29 cm3 to obtain the required absorbed dose in a range of 50–150 kGy. The results from this study can be used to determine the parameters and conditions of the machine and the irradiation system for the practical operation. [ABSTRACT FROM AUTHOR]

Bioactive glass-ceramic is a promising candidate for medical implants. The impact of Si3N4 doping on the photon attenuation properties of a newly designed bioactive glass system with the chemical composition of (55–3×)SiO2 –13.5CaO–29Na2O–2.5P2O5–xSi3N4, where x = 0, 1.76, 3.56, 5.35, and 7.17 mol%, is studied. Mass attenuation coefficient (μ/ρ) of these samples is calculated by Geant4 toolkit at photon energies ranging from 0.015 MeV up to radiotherapy energy limit namely: 10 MeV. The generated data of μ/ρ are verified using the calculated values of XCOM software. Half value layer (HVL), electron density (Neff), and effective atomic number (Zeff) are obtained for each bioactive glass involved. It is noted that HVL of these bioactive glasses increases by increasing Si3N4 content. Consequently, GP4 bioactive glass possesses the highest HVL values among the studied samples. The photon attenuation properties of GP4 glass are compared with different types of bioactive glasses and commercial glasses in terms of mean free path (MFP). Moreover, exposure and energy absorption buildup factors (EBF and EABF) are calculated for the GP4 bioactive glass at different penetration depths such as 1, 5, 10, 15, 20, 30, and 40 mfp. Additionally, removal cross section (∑R) of the present bioactive glasses is calculated. It can be concluded that GP bioactive glasses have equivalent photon attenuation properties to those of the standard bioactive glasses. Therefore, they can be safely used as an international alternative in various applications even if the exposure to gamma-ray is possible. [ABSTRACT FROM AUTHOR]

Mass attenuation coefficients ( μ m ) for some nonlinear optical materials such as potassium dihydrogen phosphate, ammonium dihydrogen phosphate, zinc tris-thiourea sulphate, and zinc thiourea chloride were measured using a 2 × 2 NaI(Tl) scintillation detector at gamma energies of 122 keV, 356 keV, 511 keV, 662 keV, 840 keV, 1170 keV, 1270 keV, and 1330 keV. In addition, GEANT4 simulations were carried out to mimic the experiment at these energies. As a result, good agreement between the experimental and GEANT4 results was observed. The measured μ m values were used to compute effective atomic numbers ( Z eff ) for the selected materials. It was found that the Z eff values were in the range typical for dosimetric materials. [ABSTRACT FROM AUTHOR]

In this study, nuclear shielding qualities of glass-ceramics with chemical composition Na 2 O 3 –BaO–PbO–Nb 2 O 5 –SiO 2 –Al 2 O 3 containing different amount of BaO and PbO were investigated. The μ ρ values were simulated using GEANT4 toolkit at 0.015–20 MeV wide energy range and the obtained results were verified by theoretical WinXCOM results. The variables such as μ ρ , HVL, MFP, Z eff , N eff , EBF and EABF were computed to determine the gamma-ray shielding performances of studied glass ceramics. The results revealed that increase in PBO and BaO percentages in glass samples has caused to decrease the HVL, MFP, EBF and EABF values and increase μ ρ , Z eff values. It has been seen that N28 and S24 samples own superior protection ability against gamma radiation. In addition, the shielding capacity of these glass ceramics against charged and uncharged particles were predicted by determination of MSP and PR values for alpha, proton and ΣR values for neutrons. It has been concluded that PbO and BaO addition improve radiation shielding competences of glass ceramics. The data obtained from this study will be beneficial for designing glass ceramics shields for radiation protection enforcements. [ABSTRACT FROM AUTHOR]

• Fragmentation cross-section of 28Si ions is calculated using GEANT4 toolkit. • Validation of Geant4 models for computational study of fragmentation cross-section is performed. • C, Al, Cu, Pb and Sn are used as target materials for high energy range of incident 28Si ion beam. • The BIC, the QMD and the INCL models are used for fragmentation cross-section studies and comparison with experimental data. • The good agreement is observed between computational and experimental results. The comparison of simulated data with experimental results is needed for the accuracy and reliability of the transport codes. In this work, we performed a comparative study of simulated results of projectile fragmentation cross-sections (PFXS) for three different models. The obtained results also compared with published experimental data. For simulation purposes, the GEANT4 simulation toolkit based on the Monte Carlo (MC) codes is used. The models in Geant4 employed to compute the PFXS are the Binary Cascade (BIC), the Quantum Molecular Dynamics (QMD), and the Intranuclear cascade (INCL). In the present study we reported the interaction of 28Si ion beam for the energy range 270–1200 A MeV incident on carbon (C), aluminium (Al), copper (Cu), tin (Sn), and lead (Pb) targets. The QMD, the BIC, and the INCL model coupled with the de-excitation models reproduce the results in agreement with experimental fragmentation cross-sections. [ABSTRACT FROM AUTHOR]

This paper examines radiation-shielding abilities of oxyfluoro-tellurite-zinc glasses in the chemical form of AlF3–TeO2–ZnO under the substitution of AlF3 by ZnO. Gamma-ray- and neutron-shielding properties were tested in terms of mass attenuation coefficient (μ/ρ), half value layer, mean free path, effective atomic numbers (Zeff), effective electron density (Neff) and removal cross-section (ΣR). The μ/ρ values of the glasses were generated by Geant4 simulations over an extended energy range and then the generated data were confirmed via XCOM software. The results showed that both gamma-ray- and neutron-shielding efficiencies of the selected glasses evolved by substituting of AlF3 by ZnO. Nuclear radiation-shielding abilities of the current glass systems were compared with that of some conventional shielding materials and newly developed HMO glasses. It can be concluded that oxyfluoro-tellurite-zinc glasses could be useful to design novel shields for radiation protection applications. [ABSTRACT FROM AUTHOR]

In this study, fast neutron removal cross-section and γ -ray shielding capabilities in terms of mass attenuation coefficient ( μ m ), transmission fractions (T), effective atomic numbers (Z eff ), half-value layer (HVL) and exposure build-up factors (EBF) of the 64 TeO 2 + 15 ZnO + (20 - x) CdO + x BaO + 1 V 2 O 5 ( x = 0 , 5 , 10 , 15 , 20 mol%) glass system have been evaluated using Monte Carlo simulations carried out with Geant4 model of the high-purity germanium (HPGe) detector and Phy-X database software. The results of this study revealed that γ -ray shielding capability of the studied glass system increases with the increase of BaO content and decrease of CdO content in the chemical structure due to the high atomic number (Z) of Ba compared to Cd. The results also showed that increase of BaO fraction in the glass structure weakens the neutron shielding ability and by the use of low Z elements in the composites better shielding performance against neutrons can be obtained. [ABSTRACT FROM AUTHOR]

In this study, mass attenuation coefficient ( μ m ), transmission fractions (T), effective atomic numbers ( Z eff ) and half-value layer (HVL) of the x PbO – (50 - x) BaO – 50 B 2 O 3 (where x = 10 , 20 , 30 , 40 mol % ) glass system have been determined from the Monte Carlo simulations carried out with Geant4 and Fluka simulation toolkits and WinXCOM database software. The calculated results were compared with the experimentally obtained μ m values of the selected glass in order to validate the Geant4 model of HPGe detector and Fluka model of NaI(Tl) detectors. T, Z eff and HVL shielding parameters of the studied glass system indicate that increase of PbO content from 10 to 40% results in a better shielding behaviour thanks to the high atomic number of lead. [ABSTRACT FROM AUTHOR]

In this study, high performance for radiation shielding, new type brick samples have been designed and produced, these containing in different percentages materials such as silicon dioxide, chromium oxide, aluminium oxide, hematite, bismuth oxide, manganese oxide, barium titanate oxide, titanium oxide calcium oxide, nickel oxide, zirconium oxide, lead oxide. Fast neutron shielding parameters, such as total macroscopic cross section effect, mean free path and transmission number have been calculated by using Monte Carlo Simulation Geant4 code. Neutron absorbed dose experiments have been carried out by using 4.5 MeV energy 241Am-Be fast neutron source and BF3 gas neutron detector. The obtained results have been compared with paraffin and conventional concrete, to determine the radiation shielding capacity of new brick samples. Some interaction parameters for gamma radiation, such as the mass attenuation coefficient and half-value layer (HVL) have been calculated by using WinXCom software, the results have been compared with conventional and basalt heavy concrete. It is found that, the new type brick samples show good shielding capacity for both neutron and gamma radiation. These new type brick samples can use has been determined for shielding material, in nuclear medicine, in the storage of radioactive waste and nuclear power plants. [ABSTRACT FROM AUTHOR]

X-ray photons attenuation characteristics for the two tellarite based glasses Bi 2 O 3 – B 2 O 3 – TeO 2 – TiO 2 and PbO–ZnO–TeO 2 –B 2 O 3 have been investigated at dental diagnostic energies (between 30-80 keV) using Geant4 code and WinXcom software. The correlation coefficient (R2) is utilized to evaluate the extent to which Geant4 results are related to the WinXcom data. For the both series, R2 is close to 1 for all samples and this implies a perfect degree of association between the Geant4 and WinXcom data. The linear attenuation coefficient is proportionally increased with addition of TeO 2 in both series, which implies that there is a decreasing tendency in the X-ray photon transmission corresponding with an increase in the TeO 2 content in the glasses. The half value layer (HVL) decreases as the density increases and this decreasing is very notable at 70 and 80 keV. The maximum HVL for all samples occurs at 80 keV and this implies that the HVL gradually increases as the energy of the X-ray photons increase. Also, the increment of TO 2 in the glasses (in both systems) leads to reduce the mean free path and BiTeTi6 and PbTeB6 samples have the lowest MFP. The MFP for both systems was compared with three heavy concretes and the comparison revealed that the selected systems can be utilized to fabricate protection masks used during diagnostic radiation of the head or oral cavity. [ABSTRACT FROM AUTHOR]

A method for optimizing the configuration of the shield from ionizing radiation for the facility analyzing the elemental composition of rocks, which is installed at the Department of Applied Nuclear Physics of the National Research Nuclear University MEPhI. Optimization is performed by the methods of mathematical simulation of the distribution of the equivalent dose rate generated during the facility operation. The Geant4 toolkit is used as the simulation environment. The influence of construction elements of the facility and the objects at the laboratory on the dose value is analyzed. In addition, the simulation results are validated by comparison to the data of dosimetry measurements. In conclusion, the possibility of using the algorithm presented for the design of biological shields from ionizing radiation sources is shown. [ABSTRACT FROM AUTHOR]

Using the Geant4 software package, a numerical simulation of a neutron source of the time-offlight spectrometer GNEIS created on the basis of the SC-1000 synchrocyclotron with 1 GeV proton energy at the NRC Kurchatov Institute—PNPI (Gatchina) has been carried out. The influence of the structural features of the neutron source of the spectrometer on the spatial and energy distributions of neutrons has been studied. The intensity and spectral characteristics of the neutron flux in the range of 1–1000 MeV have been determined on the basis of the obtained information and detailed allowance for all elements of the neutron beam guide system. It is found that the best agreement between the experiment and calculation performed by means of Geant4 is observed when using the QGSP_INCLXX_HP model. In the neutron energy range of 1–200 MeV, the difference between the experimental and calculated shapes of the spectra is less than 25%. [ABSTRACT FROM AUTHOR]

The goal of this research is to investigate the influence of three heavy metal oxides (Bi 2 O 3 , BaO and TiO 2) on the gamma rays shielding effectiveness of borosilicate glasses. The Geant4 simulation code has been applied to estimate the mass attenuation coefficients (μ/ρ) of 30B 2 O 3 –(70-x)SiO 2 –xHMO glass systems (where HMO are Bi 2 O 3 , BaO and TiO 2 with 0, 1, 2, 3, 4 and 5 mol%). We estimated the μ/ρ values at six energies (i.e. 0.347, 0.511, 0.826, 1.173, 1.275 and 2.506 MeV). To determine the accuracy of the obtained results, we compared the Geant4 data with those calculated using WinXcom software. The obtained Geant4 values of the selected borosilicate glasses with different concentrations of Bi 2 O 3 , BaO and TiO 2 agreed quite well with the WinXcom results at all energies. The addition of Bi 2 O 3 and BaO increases the μ/ρ values, while the samples doped with TiO 2 showed insignificant changes in μ/ρ values with the addition of TiO 2. All the presented samples have lower HVL than the undoped glass sample (70SiO 2 -30B 2 O 3 sample). This means that the addition of the three dopants (Bi 2 O 3 , BaO and TiO 2) have led to a decrease in the HVL which enhances the attenuation performance of the current samples. [ABSTRACT FROM AUTHOR]

Tellurite based glasses have been of considerable interest in the last decades due to their interesting mechanical, physical and chemical features. Presently, different investigators and engineers are being devoted for developing the Tellurite based glasses to be used as effective radiation shielding materials. Our aim is to study the energy as well as PbO content dependence on the gamma rays attenuation behavior of lead tellurite glasses when the PbO content changes from 0 to 30 mol% between 0.356 and 2.506 MeV photon energies. This was achieved by considering the lead tellurite glass system with the composition x(PbO)-(100-x)(TeO 2). The photon attenuation factors of the lead tellurite glasses were evaluated at five energies utilizing Monte Carlo simulation (Geant4 code). The reative difference values between Geant4 and XCOM data for the six glasses are less than 7% and this validates the accuracy of the obtained results. The mass attenuation coefficient (μ/ρ) reduces with an increase in the energy whereas it increases when TeO 2 is replaced by PbO. The influence of PbO on the μ/ρ is significant only at 0.356 and 0.511 MeV, but at the other energies it is found that PbO slightly affects the attenuation factor. The linear attenuation coefficient of 30PbO–70TeO 2 (coded as TePb6) is higher than the other samples. The effective atomic number has the maximum value at 0.356 MeV (in the range of 27.76–41.25). We compared the mean free path for the tellurite glasses with RS-520 and RS-360, Osmani, nasir and PHP glasses. The results reveal that the lead tellurite glasses (especially the samples with high PbO content) are a candidate as protection materials from hazardous radiation and have better attenuation in comparison to some nuclear engineering materials. [ABSTRACT FROM AUTHOR]

Glass samples of titanium-lead bismuth borate with the composition of (60B 2 O 3 – 20Bi 2 O 3 – (20-x)PbO – xTiO 2), where 0 ≤ x ≤ 10 wt% labeled as BBPT0.0 (x = 0) to BBPT10.0 (x = 10) were synthesized. The melt quenching technique was used in the preparation. The amorphous character and vibrational groups for all samples were confirmed through XRD and FTIR measurements, respectively. The optical band gap (E opt), Urbach's energy (E urbach), and the optical dispersion constants have been determined using UV–Vis spectra. Results reveal that the values of the optical band gap energy exhibit a decrease with the TiO 2 concentration, in contrast with Urbach's energy which displays a linear increase from 0.43 to 0.64 eV. In addition, the values of single-oscillator energy (E o) has the same behavior of the optical energy gap (E opt), while the dispersion energy parameter (E d) has an inversely behavior. Mass attenuation coefficients (μ/ρ) of the investigated glasses have been computed using the Geant4 simulation toolkit and WinXCOM database software. Geant4 model of a HPGe detector has been employed to perform the Monte Carlo simulations for the glass samples with five thicknesses from 1 to 3 cm at the gamma ray energies in the range of 356–2510 keV. The transmission fractions as a function of the thickness at 356 keV photon energy for all studied glasses has been performed. Half value layer (HVL) was derived from the μ/ρ values. Results showed the studied glasses have good shielding capability according to their mass attenuation coefficients, transmission fractions and HVL values. Schematic of the Geant4 set-up used to make Monte Carlo simulations for the determination of the mass attenuation coefficients. Image 1086 • Samples of B 2 O 3 -Bi 2 O 3 -PbO-TiO 2 were prepared. • XRD, FTIR, and UV-Visible measurements have been carried out. • Optical properties and dispersion constants were evaluated. • μ/ρ and HVL for glasses were evaluated using the Geant4 simulation and WinXCOM program. • Studied glasses have a significant improvement in the γ-photons attenuation. [ABSTRACT FROM AUTHOR]

A significant challenge to current and future manned and/or unmanned space missions is due to deep space radiation. An improvement in more realistic (more accurate) simulation models in predicting the effects of radiation within the spacecraft is required, especially to better predict dose to astronauts, energy deposition within sensitive electronics, and effectiveness of radiation shielding for long-term space missions. The International Space Station provides an invaluable resource for long-term measurements of the radiation environment in Low Earth Orbit (LEO); however, the only manned missions with dosimetry data available beyond LEO are the Apollo missions. Thus the physiological effects and dosimetry for deep space missions are not well understood in planning extended missions. GEANT4, a Monte Carlo method, represents a powerful physics simulation tool to assess the effects of radiation transport through spacecraft. The newest version of GEANT4 supports multithreading and Message Passing Interface (MPI) allowing for much faster distributive processing of simulations, using a high-performance computing environment. This paper introduces a new simulation model and application using GEANT4 that greatly reduces computational time to hours instead of weeks without any post simulation processing based on high-performance computing. This paper also introduces a new set of GEANT4 computational detectors for calculating dose distribution, besides the historically used International Commission of Radiation Units simulation spheres. The computational detectors include a thermoluminescent detector, tissue equivalent proportional counter, and human phantom, along with additional new scorers to calculate dose equivalence based on the International Commission of Radiation Protection standards. This study presents GEANT4 simulations of the dose deposition for the International Space Station and the Apollo 11 and 14 missions, which replicate well the dose measurements during these missions. The simulations of both Apollo missions show consistent doses from galactic cosmic rays and radiation belts with a small variation in dose distribution across the Apollo capsule. The greatest contributor to radiation dose for both Apollo missions in the simulations came from galactic cosmic rays. Simulations of historical solar particle events during an Apollo missions show a solar particle event would not be fatal and below mission limits. These GEANT4 models also provides the values of the dose deposition and dose equivalent for various organs within a human phantom in the International Space Station and Apollo command module, which are developed for the first time using this GEANT4 based application. • A new application simulated radiation through full-sized spacecraft. • Application implemented new computational detectors including human phantom. • Simulations of dose for ISS and Apollo 11 matched well experimental measurements. • Greatest contributor to radiation dose for Apollo missions was from GCR. • Simulations of Apollo 14 showed higher measured dose most likely due to SPE. [ABSTRACT FROM AUTHOR]

This paper describes the development of a non-destructive method for analysis of pure-beta minus radioactive sources. An experimental set-up based on plastic scintillation detection system was built for this purpose. It was tested using standard 90Sr/90Y radioactive sources. The experimental results were compared to theoretical calculations based on Fermi's beta decay theory as well as with Monte-Carlo simulations using a predefined GEANT4 code named rdecay01. All the obtained results showed to be in good agreement. [ABSTRACT FROM AUTHOR]

• Estimating the deposited dose to a person who is in contact with a patient undergoing Nuclear medicine procedures is an major task. • Our "Merge Phantoms Tool" can read and merge two voxel phantoms in DICOM format. • Merged phantom can be inputted into the GAMOS software to calculate the deposited dose that a phantom receives from the other. • An accurate deposited dose calculation can be used for radiation protection or the release of a patient from isolation. This report introduces a tool for merging two voxel phantoms to calculate the deposited dose that a person receives from a patient undergoing Nuclear medicine procedures. The phantoms must be converted to the text format used by GEANT4 to treat DICOM images via the GAMOS utilities. The Merge Phantoms Tool can merge two phantoms in two different cases: standing either side by side or opposite. The merged phantom is also in text format and is subsequently input back into GAMOS to calculate the equivalent dose that a person receives from a patient. The equivalent doses to the eyes of people in contact are calculated in a case where a patient was administered 185 MBq of 18F-FDG during a PET examination. The corresponding doses when the two phantoms are standing opposite are greater than those when they are standing side by side and smaller than those from point and tube source calculated by Sumi Yokoyama at any distance. The Merge phantoms tool and GAMOS software can be used to calculate the deposited dose that a person receives from a patient. An accurate dose calculation can be used for radiation protection, or deciding whether a patient can be released from isolation if the dose is small even in a close contact. [ABSTRACT FROM AUTHOR]

The goal of this study is to provide a benchmark for the use of Monte Carlo simulation when applied to coincidence summing corrections. The examples are based on simple geometries: two types of germanium detectors and four kinds of sources, to mimic eight typical measurement conditions. The coincidence corrective factors are computed for four radionuclides. The exercise input files and calculation results with practical recommendations are made available for new users on a dedicated webpage. • Examples of the use of Monte Carlo simulation to calculate coincidence summing corrections. • Simple cases with two types of germanium detectors and four kinds of sources were investigated. • Calculation of coincidence summing correction factors for 60Co, 134Cs, 133Ba and 22Na is presented. • Input files, correction factors and recommendations are available on a dedicated webpage. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenide (TMD) materials are emerging candidates for next-generation electronics due to their unique properties, such as high carrier mobility and on/off ratios. However, their introduction may significantly alter single-event effects (SEEs) in devices compared to traditional silicon devices. This work investigates the SEE sensitivity of TMD devices under proton irradiation using the Geant4 simulation toolkit. Secondary ions generated by proton irradiation of TMD devices with different proton energies were simulated and analyzed. The energy deposition in the device's sensitive volume array was also examined. The results show that TMD devices are more susceptible to SEEs than silicon devices, and that their SEE sensitivity depends on the TMD material, proton energy, and critical charge. These findings provide valuable insights into the aerospace application of TMD material devices and the design of radiation-hardened TMD-based electronics. [ABSTRACT FROM AUTHOR]

Shielding capacities of gamma and neutron radiations of concrete samples with bronze addition and boron carbide at different rates were investigated within the scope of this study. In order to examine the gamma radiation shielding capacities of the produced bronze doped concrete samples, linear attenuation coefficients mass attenuation coefficients, half thickness values layer, one-tenth thickness values layer, effective atomic number and radiation protection efficiency parameters were analyzed using experimental, theoretical (WinXCOM) and simulation (GEANT4 and FLUKA) codes. The gamma radiation shielding capacities of the produced concrete samples were investigated at different energies ranging from 59.5 to 1332.5 keV. The results showed that increasing the amount of bronze in the produced sample attenuated more amount of gamma comparing to the samples that had less bronze. The best sample among the produced concretes was found to be the sample that doped with 50% bronze. Then, different proportions of boron carbide (B 4 C) were substituted into the sample content (50% bronze) to produce a new concrete doped with bronze and B 4 C. The neutron shielding abilities of the new concrete samples produced in this way were investigated with the GEANT4 and FLUKA simulation codes. Using different thicknesses and energies the neutron shielding property of the samples was analyzed to test neutron transmission. The results showed that the sample doped with 20% boron carbide was the best attenuator against neutron radiation. • Bronze and B 4 C doped concrete samples were produced. • Gamma and neutron radiation capabilities of the produced concrete samples were investigated. • Gamma radiation shielding parameters of the produced samples were determined experimentally. • Neutron shielding capacities were investigated with GEANT4 and FLUKA. • Gamma radiation shielding properties improved with increasing bronze amount. [ABSTRACT FROM AUTHOR]

Monitoring the level of radioactive contamination and the type of radiation in the environment is very important for the protection of facilities, employees, and people. Phoswich detector is one of the useful tools to identify different radiations and separate them from each other using different scintillating crystals. However, their design can be very diverse based on the type of particles analyzed and various parameters of scintillating crystals and needs optimization to have maximum efficiency. This work aims to optimize the scintillating crystal layers for the design of the three-layer alpha-beta-gamma phoswich detector based on Monte Carlo radiation transport calculations. The selection of the appropriate model for the type and thickness of each layer is based on the optimization of parameters such as energy accumulation, produced scintillation optical photons, attenuation of optical photons, and scintillation decay time. The results showed that the three scintillating layers of ZnS(Ag), CaF 2 (Eu), and LYSO(Ce) with optimal thicknesses of 25.01 μm, 3.50 mm, and 2.54 cm, respectively, have more suitable optical outputs for detecting common alpha-beta-gamma radionuclide emitters. • Different scintillating crystals were investigated for various radiations. • Modeling of three-layer scintillating crystal layers was carried out. • An optimal configuration for a phoswich detecting alpha-beta-gamma was obtained. • Monte Carlo calculation was used to investigate phoswich parameters. [ABSTRACT FROM AUTHOR]

We have validated the predictions of SAPTON, and Geant4 models QGSP-INCLXX, and SHIELDING, with the experimental charge cross-sections of 16O ＋ Al reaction at beam energies ranging from 290 MeV/u to 1000 MeV/u. SAPTON exhibits reasonable agreement with the data compared to Geant4 models. While Geant4 favors the intra-nuclear cascade process to produce particles with charge Z ≤ 2, in abundance, SAPTON favors the breakup into projectile-like and target-like fragments, and hence shows better agreement with the data. [ABSTRACT FROM AUTHOR]

Low background gamma spectrometry employing HPGe detectors is a sensitive technique for measuring low-level radioactivity in environmental applications, material screening, and for rare decay searches. This work presents spectroscopic performance evaluation and modeling of a low background measurement setup developed at IIT Ropar in Punjab, India, to measure trace natural radioactive elements, with a particular interest in studying low-level radioactivity in soil and/or rock samples to generate specific inputs for low background experiments. The performance test and characterization of a low background cryocooled HPGe detector with relative efficiency of ∼ 33% have been carried out. An effective detector model has been developed using GEANT4 Monte Carlo simulation to determine the response of the detector over an energy range of 80.9–1408 keV and compared with the experimental performance of the detector. The response of the detector obtained using Monte Carlo simulations agrees reasonably well within 93% level of confidence, indicating only 7% deviation in the comparison. The present setup offers improved detection limits of primordial radionuclides (U/Th and K) to measure radioactive contamination in environmental matrices, which has been used elsewhere (Thakur, 2023). [ABSTRACT FROM AUTHOR]

A shield structure with five collimating tubes has been designed in a vertical neutron camera (VNC) on HL-3. Polyethylene is used to screen scattered neutrons, and the lead layer is applied to obstruct the stray X-rays and γ -rays in the environment, as well as secondary γ -rays produced by neutrons interacting with materials. The shielding effect of the structure is studied by using GEANT4. The energy spectra of the incident neutrons and the rate of direct neutrons at the end of five channels are obtained, which demonstrates that the design of shield achieve the criteria as we excepted. • Designing a vertical neutron camera for HL-3. • A compact collimating shield structure with five channels. • Examining the shield ability and optimizing the structure by GEANT4. • Calculating the neutron flux identified by detectors in the simulation. [ABSTRACT FROM AUTHOR]