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• This paper presented the theoretical model of backscattered electron emission BEE, and the universal formulas for some parameters such as η (h , E po , Z), f (x , E po , Z and S (E po , Z) mean at E po = 20–100 keV were deduced, respectively. • The special formulas for some parameters such as η (h , E po , Z), f (x , E po , Z) and S (E po , Z) mean at E po = 20–100 keV of Au, Ag, Al, Cu, Bi and Pb were obtained and proved correct, respectively. • The special formulas for some parameters such as η (h , E po , Z), f (x , E po , Z) and S (E po , Z) mean of W and Mo were also obtained and proved correct, respectively. This paper presented the theoretical model of backscattered electron emission BEE, and the universal formulas for some parameters such as η (h , E po , Z) and f (x , E po , Z) at E po = 20–100 keV were deduced, respectively; where E po is the incident energy of primary electron, f (x , E po , Z) is maximum penetration depth distribution of emitted backscattered electron BE from atomic number Z bulk metals penetrated by primary electrons at E po , x is the distance from incident surface to the position where primary electrons are reflected back, η (h , E po , Z) is the backscattering coefficient at E po of Z metal films with film thickness h. From the deduced universal formula for η (h , E po , Z) and the relationships among the parameters of BEE from Au, W, Ag and Mo, the special formulas for some parameters such as η (h , E po , Z) and f (x , E po , Z) of W and Mo were also obtained and proved correct, respectively. [ABSTRACT FROM AUTHOR]

The application of a potential model to the analysis of differences between the Auger parameters of InSb and the elemental materials yields a value 1.82 ± 0.07 Å for the core hole screening distance in InSb. It also yields a value of 0.22 ± 0.49 e for the charge transfer in InSb. Shifts in the Auger parameters of elements between their metallic states and in a compound semiconductor are interpreted using a novel method based on quantifying atomic core potential, as a quantum mechanical observable, in terms of its dependence on the valence charge and the number of atomic core holes. The core hole screening distance is ∼ 30 % larger than half the interatomic distance between the nearest neighbors and, by the equivalent cores model, is expected to be the screening radius of Sn and Te impurities in InSb. • The main achievement of this paper is to determine the core hole screening distance in InSb. • The paper shows this has a value of 1.82 ± 0.07 Å. • The paper also establishes a method of determining charge transfer in semiconductors though the accuracy of this determination is rather poor: 0.22 ± 0.49 e. [ABSTRACT FROM AUTHOR]

We have used the TOPAS Geant4-based package to create a parametric simulation of a new TOF-PET scanner design based on a low atomic number scintillator. TOPAS was extended to provide complete information on individual particle position, energy, and identity, allowing access to all particle interactions in the simulation. The data were then used as the 'truth' information of particle kinematics for the simulation of the TOF-PET scanner, as described in a separate paper. The Derenzo and XCAT phantoms were added to the simulation with in-patient scattering, positron emission placement, and positron diffusion. Running Geant4 simulations through TOPAS requires substantially smaller amounts of user training than would be needed in raw Geant4. This paper describes the methods used to simulate the low-Z whole-body scanner at reduced dose. Specifically, this paper covers the simulation of the FDG decay energy spectrum; the simulation of tissue densities, atomic compositions, and radiotracer doses within imaging phantoms with doses; the custom TOPAS extension used to record particle interaction data; computational performance; and required Geant4 libraries used in TOPAS. [ABSTRACT FROM AUTHOR]

Contrast-enhanced computed tomography (CT) is an indispensable technique in modern diagnostic medicine because it not only allows non-destructive, three-dimensional observation of the inside of the body but also provides images that highlight lesions. Recent developments in photon-counting (PC) CT systems have enabled contrast-enhanced CT scanning and quantitative evaluations, such as material discrimination and concentration estimation of contrast agents, using X-ray energy information. We established a PC-CT system that combines fast scintillators and multipixel photon counters (MPPCs) and demonstrated its performance. In this paper, we report the imaging performance of a PC-CT system using a mixture of contrast agents containing gadolinium and iodine. We performed CT imaging of a static phantom containing a mixture of the two contrast agents. The concentration of each contrast agent from the CT images in multiple energy bands were estimated. We succeeded in obtaining the concentration distributions for each contrast agent and verified the possibility of discriminating between two substances with different atomic numbers. In addition, the same procedures and analytical methods used for the static phantom were applied to the in vivo imaging of a mouse, in which gadolinium- and iodine-containing contrast agents were injected at different time intervals. We also succeeded in discriminating between the two contrast agents in vivo, making it possible to provide new imaging diagnostics such as the determination of necrotic tissues and normal blood vessels. Furthermore, we succeeded in creating three-dimensional concentration maps of gadolinium and iodine in a mouse, demonstrating the great potential of MPPC-based PC-CT for future clinical applications. • A silicon photomultiplier-based photon-counting CT system was established. • The concentration of iodine and gadolinium mixed contrast agents can be estimated. • Correction by Monte Carlo simulation improves the accuracy of the estimation. • The transition of the two contrast agents flowing in vivo is visualized. [ABSTRACT FROM AUTHOR]

Apatite-wollastonite (AW) is an important biomaterial useful in clinical practice for tissue engineering and other applications. In this research paper, AW and B 2 O 3 -doped AW glass ceramics (GCs) were reported and investigated deeply by means of their ability to attenuate gamma-photons. The studied samples denoted by AW, AW-10B, and AW-20B as the B 2 O 3 content from 0 to 20 mol% with the step of 10. Using FLUKA and other theoretical approaches, photon interaction parameters for narrow and broad beam transmission through the AW GCs were estimated for the 15 keV–15 MeV energy range. Also, the density of the GCs increased as the B 2 O 3 content increased. The mass attenuation coefficients were found to be within the ranges 0.0231–13.5659 cm2/g, 0.0225–12.3561 cm2/g, and 0.0220–11.1079 cm2/g for AW, AW-10B, and AW-20B, respectively. The effective atomic number of the GCs fell within the range 11.04–17.26, 10.88–17.01, and 10.21–16.72, respectively. As the doping concentration of B 2 O 3 increased, the gamma energy that the AW GCs were able to absorb decreased. The addition of B 2 O 3 compromised the photon shielding competence of AW in both narrow beam and broad beam scenarios. The GCs had better photon-absorbing competence than some existing gamma-photon shields. The GCs may thus be used as photon absorbers in clinical practice or in other nuclear applications. • Gamma attenuation of AW ceramic system is reported. • Experimental work is carried out. • Monte Carlo simulations are employed. • Dose rate and buildup factors are evaluated. • GCs had better photon-absorbing competence. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of ZnCl 2 on the gamma attenuation and radiation shielding properties of tellurite glasses incorporating Bi 2 O 3 and B 2 O 3. Employing Geant4 simulation and XCOM program, the study explores the impact of varying ZnCl 2 content on different gamma attenuation parameters such as linear attenuation coefficient (μ), radiation protection efficiency (RPE), effective atomic number (Z eff), and HVL. Moreover, the relation between these factors and the density of the studied glass system is discussed in details. It is found that the incremental addition of Bi 2 O 3 significantly enhanced the photon attenuation properties of the tellurite glasses involved. The maximum Zeff values are observed at the low energy region between 0.015 and 0.1 MeV with the values of 53.016, 60.133, 65.950, 70.370, and 73.791 for the glass samples namely TBBZC1, TBBZC2, TBBZC3, TBBZC4, and TBBZC5, respectively. Furthermore, the HVL values fall between 0.0016 cm and 4.3546 cm indicates that the current glass system can be utilizes for gamma shielding applications. The results provide insights into the potential enhancement of radiation shielding efficiency in tellurite glasses, contributing valuable knowledge for the development of advanced materials in nuclear safety applications. • Radiation protection of TeO 2 –ZnCl 2 –B 2 O 3 –Bi 2 O glass system. • Significant influence of ZnCl 2 on the radiation shielding. • Monte Carlo simulations are employed. • A good agreement between the theory and the simulation. • TBBZC5 system has a potential use in nuclear and medical applications. [ABSTRACT FROM AUTHOR]

Abstract The role of active-interrogation systems for nuclear security is to detect the presence of special nuclear material inside an object by observing the radiation emitted by that object when it has been exposed to known sources of external radiation. Because of the cost, complexity, and the need to avoid irradiating occupants, active-interrogation systems are intended for cargo applications where shielding can prevent detection by passive radiation detection systems. To ensure that active-interrogation systems for detection of special nuclear material are designed and tested to a consistent level of performance, technical standards are needed for evaluating such systems. This paper addresses the testing standards needed for active-interrogation systems to detect high atomic number materials, fissionable materials, and specific special nuclear materials. Because the use of special nuclear material for a testing standard is not practical, this work focuses on the determination of materials that could be used as surrogates in that they provide a similar response as targets of special nuclear materials. The results of this paper, determined through analytic calculations and radiation transport modeling, are based upon scenarios constructed and applied to specific active-interrogation modalities. [ABSTRACT FROM AUTHOR]

Monte Carlo methods have become ubiquitous in our society. Although statistical estimation methods date to earlier times, Monte Carlo (MC) methods were born in 1949 with publication of the paper by Metropolis and Ulam (1949). We address some of the many ways that MC methods have evolved over the years. Specifically, we consider electron transport calculations by MC, improvements in sampling efficiency afforded by the discrete alias sampling method, and solution of inverse problems by the Symbolic Monte Carlo (SMC) method. As a graduate student, one of us (WLD) used MC to estimate the improvement of cylindrical Geiger-Müller tube efficiency at low energies due to use of a thin coating of high atomic number material on the inside tube surface. Our methods were approximate but the results were reasonably good. We will discuss how discrete alias sampling—introduced in 1974—can improve the sampling efficiency significantly over simple table look-up. Finally, we consider an inverse problem in which the form of the governing probability density function is unknown but desired. We also briefly address matters of perspective on use of MC methods. N. Metropolis, S. Ulam, The Monte Carlo Method, 1949, J. Am. Stat. Assoc. 44 , 335–341. • Comparison of simplified electron transport model with MCNP model. • Brief review of discrete alias sampling. • Example symbolic Monte Carlo problem. • Discussion of direct and inverse Monte Carlo formalisms. [ABSTRACT FROM AUTHOR]

Recently CMOS active pixel sensors have been used in Hadrontherapy ions fragmentation cross section measurements. Their main goal is to reconstruct tracks generated by the non interacting primary ions or by the produced fragments. In this framework the sensors, unexpectedly, demonstrated the possibility to obtain also some informations that could contribute to the ion type identification. The present analysis shows a clear dependency in charge and number of pixels per cluster (pixels with a collected amount of charge above a given threshold) with both fragment atomic number Z and energy loss in the sensor. This information, in the FIRST ( F ragmentation of I ons R elevant for S pace and T herapy) experiment, has been used in the overall particle identification analysis algorithm. The aim of this paper is to present the data analysis and the obtained results. An empirical model was developed, in this paper, that reproduce the cluster size as function of the deposited energy in the sensor. [ABSTRACT FROM AUTHOR]

The aim of this paper is to the synthesis of ZnO– Bi 2 O 3 nanocomposites and characterization their optical, structure, and radiation shielding properties. The microwave –assisted hydrothermal method was adopted for the synthesis of ZnO– Bi 2 O 3 nanocomposites coded as 100Z, 25B075Z, and 50B-50Z. The FTIR and UV spectra of the samples were analysed to obtain their optical and chemical structure features. Also, the gamma-ray photon shielding parameters of the nanocomposites were evaluated using the EPICS2017 data library and by Geant4 Monte Carlo simulations for photon energies 1 keV–10 MeV. The FTIR spectrum analysis confirms the chemical bond structure of the samples. On the other hand, the optical bandgap of the nanocomposites decreased from 3.3 to 2.95 eV as the Bi 2 O 3 nanoparticles increased in the samples. Obtained values of the mass attenuation coefficients of the samples increased in the order of 100Z, 25B075Z, and 50B-50Z. Value of the effective atomic number varies from 13.91 to 29.55, 20.30–55.97, and 26.70–68.97 for 100Z, 25B-75Z, and 50B-50Z correspondingly. The 100Z, 25B075Z, and 50B-50Z nanocomposites were found to have comparable photon shielding ability with respect to high density common commercial glass shields. The present nanomaterials could be adopted as additives to enhance photon shielding competence of existing composite materials. [ABSTRACT FROM AUTHOR]

This paper concerns the verification of continuous-time polynomial spline trajectories against linear temporal logic specifications (LTL without 'next'). Each atomic proposition is assumed to represent a state space region described by a multivariate polynomial inequality. The proposed approach samples a trajectory strategically, to capture every one of its region transitions. This yields a discrete word called a trace, which is amenable to established formal methods for path checking. The original continuous-time trajectory is shown to satisfy the specification if and only if its trace does. General topological conditions on the sample points are derived that ensure a trace is recorded for arbitrary continuous paths, given arbitrary region descriptions. Using techniques from computer algebra, a trace generation algorithm is developed to satisfy these conditions when the path and region boundaries are defined by polynomials. The proposed PolyTrace algorithm has polynomial complexity in the number of atomic propositions, and is guaranteed to produce a trace of any polynomial path. Its performance is demonstrated via numerical examples and a case study from robotics. [ABSTRACT FROM AUTHOR]

We present the results concerning the development in Geant4 of a new data driven library, called here the ANSTO HF library. This X-ray fluorescence library is based on an approach of particular interest for PIXE simulation applications; however, it can be used in any Geant4 applications where X-ray fluorescence needs to be described. The X-ray fluorescence transition probabilities were calculated within the Hartree-Fock (HF) approach, which is recognised to better reproduce PIXE experimental values compared with the Hartree-Slater approach, adopted in the current default Geant4 EADL data library. These HF X-ray fluorescence transition probabilities were integrated into a new Geant4 library and will be released within Geant4 in the near future. In this paper, we compare the fluorescence X-ray spectra generated by the ANSTO HF library and by the currently available library (EADL-1991 [1]) within Geant4, for targets irradiated with protons and α particles with energies up to 10 MeV, a range of interest for PIXE applications. The comparisons were performed for a large set of sample materials spanning a broad range of target atomic numbers. These two approaches were compared to existing experimental measurements performed at the ANSTO heavy ion microprobe beamline using 2 MeV and 3 MeV proton and 10 MeV He2+ ion beams. This work represents a useful upgrade to the Geant4 atomic de-excitation package. [ABSTRACT FROM AUTHOR]

• New experimental data on fragmentation of 300 MeV/u 124-Xe in aluminum target. • Newly introduced activation depth obeys linear dependence on A/Z2 of the fragment. • The activation depth is a fragment-specific attribute of the depth-profile. • The activation depth can substitute the range and support fragment identification. • Main profile-shape categories have been introduced and described. This work is a continuation of a series of publications devoted to the depth-profiling of activity induced by high-energy heavy-ions in selected accelerator-construction materials. An aluminum target in the stacked-foil configuration was irradiated by 300 MeV/u 124Xe ions. Depth-profiles of induced activity of selected nuclides were obtained by gamma-spectroscopy of individual target foils. Special attention was paid to heavy projectile-fragments and their ranges. Main profile-shape categories have been defined to illustrate typical shapes of the measured profiles. A new quantity – an activation depth – has been introduced and its dependence on the fragment atomic and mass number has been found. It is shown that this quantity is fragment-specific and can substitute the range, which is very useful in case of the activation experiments using the stacked-foil targets with depth resolution limited by the foil thickness. Apart from gamma-spectroscopic parameters and fundamental nuclear properties of the nuclides, the activation depth can be used as an additional nuclide-attribute supporting identification of the projectile fragments and verification of the range-calculating computer codes. Although the main attention of this paper is paid to presenting the new experimental results, comparison with supporting simulations with the aid of ATIMA and FLUKA2020 is included, too. [ABSTRACT FROM AUTHOR]

As a consequence of its high atomic number density, diamond can incorporate a relatively limited range of impurities as distributed point-defects, chiefly N, B and H. A few other species can be grown-in, and other impurity species incorporated via implantation and annealing. For applications including electronic, electrical and quantum devices, the presence of states deep within the wide band-gap is of importance, and the list of potential colour centres available for exploitation continues to grow. Although B can be grown into diamond at high concentration, study of other group-13 elements is rather limited. In this paper we present the results of modelling of Al, Ga and In. We find all species readily form complexes with vacancies, and exhibit electronic structures that parallel those of the Si V complex. We report electronic structures, electrical levels, optical transitions and hyperfine interactions of the colour centres, as well as reflect upon the thermodynamics of the complexes. We suggest that co-implanting group-13 elements with nitrogen would give rise to the defect charge states with potential for quantum applications. [Display omitted] • Group-13 impurities, Al, Ga and In, form viable colour centres in diamond for quantum-based technology when co-doped with N • Colour centres may either involve a vacancy or a complex with both a vacancy and nitrogen • Predictions of observables of substitutional Al, Ga and In, their complexes with vacancies and nitrogen are reported • Implanted impurities are not expected to be observed as interstitials after annealing [ABSTRACT FROM AUTHOR]

Detection of cross-border smuggling of illicit materials and contraband is a challenge that requires rapid, low-dose, and efficient radiographic technology. The work we describe here is derived from a technique which uses monoenergetic gamma rays from low energy nuclear reactions, such as 11 B(d,nγ) 12 C, to perform radiographic analysis of shipping containers. Transmission ratios of multiple monoenergetic gamma lines resulting from several gamma producing nuclear reactions can be employed to detect materials of high atomic number ( Z ), the details of which will be described in a separate paper. Inherent in this particular nuclear reaction is the production of fast neutrons which could enable neutron radiography and further characterization of the effective- Z of the cargo, especially within the range of lower Z . Previous research efforts focused on the use of total neutron counts in combination with X-ray radiography to characterize the hydrogenous content of the cargo. We present a technique of performing transmitted neutron spectral analysis to reconstruct the effective Z and potentially the density of the cargo. This is made possible by the large differences in the energy dependence of neutron scattering cross-sections between hydrogenous materials and those of higher Z . These dependencies result in harder transmission spectra for hydrogenous cargoes than those of non-hydrogenous cargoes. Such observed differences can then be used to classify the cargo based on its hydrogenous content. The studies presented in this paper demonstrate that such techniques are feasible and can provide a contribution to cargo security, especially when used in concert with gamma radiography. [ABSTRACT FROM AUTHOR]

This paper aims to study gamma and beta attenuation characteristics of newly developed 60Se- 20Ge (20 – x)-Sb-xAg (where x varies from 0 to 20 mol% with step of 5) Chalcogenide glasses. Geant4 toolkit was utilized mainly to explore gamma-ray attenuation properties by determining linear attenuation coefficient (μ) for the chosen samples. The obtained results were compared with the theoretical approach applying via XCOM program. Then, we utilized the μ values to compute effective atomic number (Z eff) and half value layer (HVL). For the sample coded as SGSA1, the μ values are 0.191 and 0.180 cm−1 between 3 and 4 MeV, while they are 0.175 and 0.197 cm−1 between 6 and 15 MeV respectively. The HVL varied between 0.001492 and 0.001317 cm at 0.015 MeV and 0.021955–0.021439 cm at 0.05 MeV. ESTAR program was employed to investigate beta attenuation properties by estimation CSDA range and TSP factors of the incident electron. It was noted that there is a significant influence of silver on the radiation shielding characteristics of the tested materials. Moreover, we compared the studied glasses with commercial glasses and traditional concrete in term of MFP. The results showed the possibility of use the studied materials for the radiation shielding applications. [ABSTRACT FROM AUTHOR]

In this paper, the radiation shielding properties of chalcogenide glass-ceramics with the chemical composition of xCsCl-(100−x)(0.5GeS 2 -0.5Sb 2 S 3), where 0 ≤ x ≤ 40 mol%, were investigated by using Geant4 simulations, G-P method, and Phy-X/PSD program. Mass attenuation coefficient (μ/ρ), half value layer (HVL), removal cross section (RCS), exposure buildup factor (EBF), mean free path (MFP), and effective atomic number (Z eff) were evaluated to elucidate the radiation shielding competence of the present chalcogenide glass-ceramics. A good agreement was noted between the μ/ρ values of Geant4 simulations and theoretical calculations. At 15 MeV, we found that the HVL values raised from 5.276 cm to 5.728 cm as the concentration of CsCl increased from 0 to 40 mol%. Maximum Z eq values occurred at 1 MeV and were 42.20, 42.98, 43.76, 44.57, and 45.40 for GSC-A, GSC-B, GSC-C, GSC-D, and GSC-E, respectively. The results revealed that the chalcogenide glass-ceramics have radiation shielding properties superior to those of commercial glasses, and traditional concrete. [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]

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]

In this research paper, we studied the optical and nuclear shielding efficiency of newly developed BGO glasses with the following compositions (in wt%): 32Bi 2 O 3 –68GeO 2 , 42Bi 2 O 3 –58GeO 2 , 47Bi 2 O 3 –53GeO 2 , 52Bi 2 O–48GeO 2 , 62Bi 2 O 3 –38GeO 2. BGO glasses were prepared by traditional melt quenching method. To obtain the band gap values of fabricated BGO glasses, optical absorption spectra were used for evaluation of optical properties. The mass attenuation coefficients (μ/ρ) were achieved for prepared glasses at 0.015–15 MeV photon energies employing MCNPX Monte Carlo code and WinXcom program. Moreover, broad-range of nuclear shielding parameters for gamma ray, neutrons and charged particles such as mass attenuation coefficient, half value layer, effective atomic number, buildup factors, mass stopping powers, projected ranges, fast neutron removal cross sections and damage factors were calculated. The refractive index is calculated from E opt , As Bi 2 O 3 concentration is enhanced, E opt is also increased as well as the optical electronegativity and consequently the refractive index. In addition, the results showed that BIGE5 glass sample with highest Bi 2 O 3 contribution has excellent nuclear radiation shielding ability among the other fabricated glass samples. [ABSTRACT FROM AUTHOR]

This paper has focused on the investigation of gamma and neutron attenuation properties of Li 2 O–B 2 O 3 –P 2 O 5 –TeO 2 glass system. Gamma shielding parameters such as mass attenuation coefficients ( μ m ), effective atomic numbers (Z eff), half value layers (HVL), tenth value layers (TVL), mean free path (MFP), effective electron density (Ne), equivalent atomic numbers (Z eq) of investigated glass samples have been calculated in a wide photon energy range of 0.02–20 MeV using MCNPX general purpose Monte Carlo code. The calculated results for mass attenuation coefficients were compared with XCOM. In addition, exposure buildup factors (EBF) and energy absorption buildup factors (EABF) of investigated glasses were determined by using the G-P fitting method. The results showed that sample 9 with the highest density had the lowest HVL, TVL and MFP values among the investigated glasses. Moreover, effective removal cross-sections (Σ R) and transmission factors (TFs) have been calculated. The obtained results have shown that the TeO 2 additive into glass samples had a positive effect on the nuclear protection performance of the investigated glass samples. It can be concluded that the impact of TeO 2 additive for nuclear radiation shielding applications can be further investigated in different types of glass systems. [ABSTRACT FROM AUTHOR]

The first version of the PASS code was developed in 2000 on the basis of binary theory of electronic stopping, a generalization of Niels Bohr's 1913 theory of the stopping of alpha particles in matter. The code has been applied in a number of fundamental studies of energy-loss problems, including Barkas-Andersen effect and straggling as well as channeling and electron emission, and it underlies the ICRU tabulation of stopping data for ions with atomic numbers 3–16 in 25 elementary and 32 compound materials over an energy range from 25 keV/u to 1 GeV/u. We report about a major expansion of the code, so that mean energy losses can be computed for 92 ions in 92 elemental targets. Comparisons with measurements have been made over the entire energy range for which experimental data are listed in the IAEA database. The code allows to compute energy losses for arbitrary compound target materials by assuming Bragg additivity. Predictions beyond the Bragg rule are available for selected materials. In this paper we specify the underlying physics and improvements of the code during the period since its first implementation. Strengths and weaknesses are demonstrated graphically for a number of ion-target combinations. Tables for 92 × 92 ion-target combinations over an energy range from 1 keV/u to 1 GeV/u are freely accessible on the internet in the DPASS (Dataset PASS) code. [ABSTRACT FROM AUTHOR]

This paper presents a facile, two-step mechano-chemical route to exfoliate and fluorinate hexagonal boron nitride nanosheets (BNNSs). The influence of fluorine (F) chemisorption on the optical and magnetic properties of BNNSs is investigated. It has been observed experimentally, by increasing fluorine concentration, band gap lowers from ∼5 to 4.17 eV and saturation magnetization and coercivity achieved the values of 1.8322 × 10−3 emu/g and 157.25 Oe, respectively. Furthermore, results strongly supported that during synthesis there is a direct correlation between different number of few atomic layers and adsorption of fluorine atoms towards fluorination of BNNSs. Moreover, the defective boron sites are thermodynamically most stable and favorable for fluorine adsorption to form stable B–F bonds as compared to N–F bonds. Such observations are additionally supported by theoretical calculations considering various possible fluorine-based defects in h-BN nanostructure. Hence, a narrow optical band gap with a room temperature weak ferromagnetic diluted magnetic semiconducting behavior of BNNSs via fluorination will expand their usage in designing/fabricating magnetic, electronic and nano-devices. [ABSTRACT FROM AUTHOR]

A method of the oxygen isotope exchange with equilibration of the gas phase was used in order to obtain the temperature dependences of the oxygen surface exchange and diffusion coefficients of the proton-conducting oxides La 1– x Sr x ScO 3–δ (x = 0; 0.04; 0.09) in the temperature range of 600–900 °C and oxygen pressure of 1.01 kPa. The diffusion and oxygen surface exchange coefficients increase with the strontium content in oxides. The rates of the individual stages of the oxygen exchange process on the surface of the oxides were determined. The oxygen incorporation was revealed to be rate-determining for the undoped LaScO 3 oxide. However, for the strontium-doped oxides La 1– x Sr x ScO 3–δ (x = 0.04; 0.09), the difference between the rates of oxygen dissociative adsorption and oxygen incorporation decreases with increasing the strontium concentration, in a way that for the La 0.91 Sr 0.09 ScO 3−δ oxide these stages become competing. The possible reasons for these differences in oxygen surface exchange kinetics were analyzed in this paper. Using the obtained oxygen diffusion coefficients, the oxygen-ionic conductivities in accordance with the Nernst-Einstein equation, and the contributions of the oxygen-ion and proton components of the total conductivity of the La 1– x Sr x ScO 3–δ (x = 0.04; 0.09) oxides in the wet reducing atmosphere (p H 2 O = 2.35 kPa, p O 2 = 10−15 Pa) were calculated. The proton transference numbers were found to be close to unit at the wet reducing atmospheres in the temperature range of 500–600°С. • The oxygen surface exchange rates are measured in La 1− x Sr x ScO 3−δ oxides. • The oxygen diffusion coefficients are measured in La 1− x Sr x ScO 3−δ oxides. • The proton transference numbers are estimated in La 1− x Sr x ScO 3−δ oxides. [ABSTRACT FROM AUTHOR]

CaHfO 3 was investigated as a promising candidate for a scintillator because of high density and large effective atomic number. Tb-doped CaHfO 3 single crystals with various Tb concentrations were synthesized by the floating zone method, and the photoluminescence (PL) and scintillation properties were investigated. All the samples showed the highest PL emission intensity at 550 nm, and the origin of this emission was identified as 4f-4f transitions of Tb3+ by the obtained PL decay time constants. The X-ray-induced scintillation spectra showed several emission peaks in the range of 350–650 nm, which were attributed to the 4f-4f transitions of Tb3+. Based on the results of the pulse height spectra, the light yield of the 1.0% Tb-doped sample was calculated to be 12,000 photons/MeV, respectively. [Display omitted] • This paper investigated photoluminescence and scintillation properties of Tb-doped CaHfO 3 single crystals synthesized by the floating zone method were investigated. • The light yields were 8400 for 0.5% Tb, 12,000 for 1.0% Tb, and 11,000 photons/MeV for 2.0% Tb concentrations. • The light yield of 1.0% Tb-doped sample was higher than that of Bi 4 Ge 3 O 12 (8000 photons/MeV) and similar to that of CdWO 4 (15,800 photons/MeV). [ABSTRACT FROM AUTHOR]

The phase distributions and hydrogen absorption and desorption performances for YB 3 -type alloys were investigated in the paper. The compositions of the alloys can be generally divided into three categories, and the pure metal phase will disappear gradually with the increase of B-side atomic number in the YB 3 alloys. The hydrogen storage capacity and desorption rate increase first, and then decrease with the atomic number. The dehydrogenation temperatures and the molar enthalpies of the hydrides during the desorption process are also discussed. [Display omitted] • The phase compositions in YB 3 include three categories. • The phase distributions can be summarized with a quadratic curve. • The H 2 desorption enthalpies increase with the B-side atomic numbers. [ABSTRACT FROM AUTHOR]

• Paper discusses low and medium e v /a group Ti-based shape memory alloys. • A few researchers have correlated transition temperatures to electronic parameters. • Researchers have not studied the above characteristics for low e v /a group alloys. • Atomic radius of the alloys is correlated to thermal hysteresis. • Equations correlating composition and e v /a to transition temperatures are obtained. The influence of electronic parameters, such as the atomic number of the alloy (Z), valence electron concentration (c v), number of valence electrons per atom (e v /a ratio), and pseudopotential radius (P), on the phase transformation temperatures (M s , A s) of binary, ternary and quaternary shape memory alloys (SMAs) based on Ti is investigated. These temperatures (M s , A s) are correlated with the composition and e v /a of the alloys using multiple linear regression. The dependence of thermal hysteresis on the atomic radius of the alloys is also studied. The alloys investigated comprise of both low (e v /a < 5) and medium (5 < e v /a < 7.5) valence electrons groups. The phase transition temperatures are raised with an increase in e v /a ratio, Z and P for medium e v /a group alloys, while for low e v /a group alloys, the trend is quite the opposite. As c v increases, the transformation temperatures (TTs) decrease for the medium e v /a group, while they increase with c v for the low e v /a group. The two different trends observed for low and medium e v /a groups are explained in the light of elastic modulus of the alloys. The effect of Z, c v , electron orbital occupancy and alloying elements on the elastic modulus, and in turn on the temperatures of transition of the alloys, is also discussed. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we studied the gamma photon attenuation properties for different germanate glasses systems with composition Sb 2 O 3 –GeO 2 –SiO 2 –Al 2 O 3 , TeO 2 –WO 3 –GeO 2 , GeO 2 –TeO 2 /SiO 2 –PbO–CaO–Tm 2 O 3 and B 2 O 3 –GeO 2 –Gd 2 O 3 –Eu 2 O 3 –GdF 3 –BaF 2. The mass attenuation coefficients (μ/ρ) for the selected germanate glasses were calculated at different energies (between 0.015 MeV and 15 MeV) using the MCNPX code. The calculated MCNPX μ/ρ values then compared with the WinXCom data to check the accuracy in the results. The results showed that the Sb 2 O 3 replacement by SiO 2 causes a decrease in μ/ρ for Sb 2 O 3 –GeO 2 –SiO 2 –Al 2 O 3 glass system. Also, it is found that for TeO 2 –WO 3 –GeO 2 glass system, μ/ρ decreases as GeO2 content increases from 1 to 20 mol%. While for GeO 2 –TeO 2 /SiO 2 –PbO–CaO–Tm 2 O 3 glass system, the results revealed that the glass samples contain TeO 2 possess higher μ/ρ values than the samples contain SiO 2. For the B 2 O 3 –GeO 2 –Gd 2 O 3 –Eu 2 O 3 –GdF 3 –BaF 2 glasses, we found that the μ/ρ values decrease as BaF 2 is increased from 0 to 15 mol%. Moreover, it is found that 50Sb-0Ge for series 1, TWG0 for series 2, 2G4T for series 3 and X = 0 for series 4 glass samples among the studied glasses have the highest effective atomic number values. On the basis of the results achieved, 50Sb-0Ge, TWG0, 2G4T and X = 0 samples have the best radiation shielding characteristics among the selected glasses. Highlights • Radiation shielding characteristics of different germanate glasses have been investigated. • The μ/ρ for the selected germanate glasses was evaluated by MCNPX simulation code at different energies. • The HVL results for the present germanate glasses suggested that the gamma photons absorption capacity increases as the density of the sample increases. [ABSTRACT FROM AUTHOR]

It has been reported that LiF as commonly used thermoluminescent dosimeter (TLD) has a flat energy response, yet the energy dependence as radioluminescent (RL) detector has not been reported up to now. LiF is a near-tissue-equivalent material with a low effective atomic number, leading to its intrinsic virtue of flat energy response, theoretically. In this paper, Super-MC software was employed to simulate the energy deposition of LiF, the energy response of which was compared with NaI, and then the influence of the size of the detector on energy response was also investigated. Finally, the experimental verification of RL energy response was performed based on an in-house developed detector coupled LiF:Mg,Ti crystal with SiPM. The experimental energy responses (with respect to 137Cs) of three volume detector show good agreement (within ±30% in the range of 33 keV–1.25 MeV) with MC simulation results, which proved that LiF:Mg,Ti has a flat energy response, and it is feasible to obtain real-time dose-rate from count-rate collection without traditional method of hardware compensation or energy spectrum acquisition. In conclusion, this scheme can be a promising candidate for the rapid and accurate real-time dosimetry in the future, simplifying detector structure and measurement algorithm. • The energy dependence of LiF as RL detector has not been reported up to now. • MC software was employed to simulate the energy deposition of LiF. • The experimental verification of RL energy response was performed. • LiF:Mg,Ti as a RL detector showed a flat energy. • The real-time dose-rate can be obtained without energy response correction. [ABSTRACT FROM AUTHOR]

This paper investigates the microstructural, chemical, and radiation shielding characteristics of rice husk ash-based self-compacting concrete (RHA-SCC) and its precursors – rice husk ash (RHA) and ordinary Portland cement (OPC). Several radiation attenuation parameters of RHA-SCC, RHA, and OPC have been studied using EpiXS. Characterizations of these samples using FTIR, XRD, and SEM were also employed for chemical bonds, mineral phase, and morphological analysis, respectively. The XCOM data library was utilized to obtain mass attenuation coefficients (MAC) and related to EPICS2017 and EPDL97 data. From the results, prominent interaction mechanisms for RHA-SCC were photoelectric absorption, incoherent scattering, and pair production in the nuclear field. Both the mean free path (MFP) and half-value layer (HVL) values agreed to this sequence: OPC > RHA > RHA-SCC. The Z eff values recorded for high-photon energies were 13.95, 13.20, and 10.85 for RHA-SCC, RHA, and OPC, respectively. While maximum N eff was estimated at the low-energy region with values of 4.68, 4.70, and 3.89 electrons·g−1 for RHA-SCC, RHA, and OPC. Both buildup factors were highly affected by the presence of higher Z elements contained in RHA-SCC, reaching up to 200 keV at 40 MFP. For intermediate and higher-energy levels, the MAC values established this order: RHA-SCC > OPC > RHA, with the lowest deviation of 0–0.21% for EPICS2017-EPDL97 tandem. Overall, RHA-SCC has better shielding effects compared to its precursors and can cost-effectively be used as an additive in preparing radiation shielding concrete. • The MFPs and HVLs are ranked in the order of OPC > RHA > RHA-SCC. • The RHA-SCC produced the highest Z eff values, while OPC was the lowest. • Both at intermediate and high-energy regions, the RHA-SCC dominates the MAC values. • RHA-SCC proves to have better shielding effects compared to its precursors. [ABSTRACT FROM AUTHOR]

In the present paper, a universal analytical dependence of effective atomic number on the composition of matter and radiation energy is proposed. This enables one to consider the case of a strong difference in the elemental composition with respect to their atomic numbers over a wide energy range. The contribution of photoelectric absorption and incoherent and coherent scattering during the interaction between radiation and matter is considered. For energy values over 40 keV, the contribution of coherent scattering does not exceed approximately 10% that can be neglected at a further consideration. The effective atomic numbers calculated on the basis of the proposed relationships are compared to the results of calculations based on other methods considered by different authors on the basis of experimental and tabulated data on mass and atomic attenuation coefficients. The examination is carried out for both single-element (e.g., 6 C, 14 Si, 28 Cu, 56 Ba, and 82 Pb) and multi-element materials. Calculations are performed for W 1−x Cu x alloys (x = 0.35; x = 0.4), PbO, ther moluminescent dosimetry compounds ( 56 Ba, 48 Cd, 41 Sr, 20 Ca, 12 Mg, and 11 Na), and SO 4 in a wide energy range. A case with radiation energy between the K- and L 1 -absorption edges is considered for 82 Pb, 74 W, 56 Ba, 48 Cd, and 38 Sr. This enables to substantially simplify the calculation of the atomic number and will be useful in technical and scientific fields related to the interaction between X-ray/gamma radiation and matter. [ABSTRACT FROM AUTHOR]

This paper demonstrates a calculation of shielding properties in a (100-x) TeO 2 –xMoO 3 glasses where x = 20, 30, 45 and 50 mol %. Focus on the shielding parameters: mass attenuation coefficients (μ/ρ), effective atomic numbers (Z eff ), half value layers (HVL) and exposure buildup factor (EBF) values have been computed using WinXCom program with the use of G-P fitting method. Also, variation of the shielding parameters is compared with other tellurite glasses. [ABSTRACT FROM AUTHOR]

X-ray transmission imaging (XRT) is widely used for sorting materials. However, conventional single-energy and dual-energy X-ray systems have poor ability to discriminate between materials with similar atomic number (Z), and the count rate of available multi-energy XRT detectors could not support high-speed industrial applications. This paper presents the design of a detector that can potentiality achieve high-speed multi-energy X-ray imaging using Geant4 simulations. This detector consisted of five detection layers (with three scintillator materials: CsI, GOS and CdWO 4), two metal filters, which allows X-ray imaging at five energies. Validation simulation showed that the 15% more accurate than a dual-layers detector in the classification of Mg and Al alloys. • A five-layer structure scintillator imaging detector was designed using Geant4 simulations. • The energy response in each layer of this detector is clearly differentiated, permitting multi-energy X-ray imaging. • The readout equipment employed in dual-layer detectors can be used in a five-layers detector with the same imaging speed. • Stimulations showed that this imaging system can be used to differentiate between materials with similar atomic numbers, such as Mg and Al alloys. [ABSTRACT FROM AUTHOR]

A prototype of a Focused Internal Reflection Cherenkov, equipped with 16 arrays of NUV-SiPM, was tested at CERN SPS in March 2015 with beams of relativistic ions at 13, 19 and 30 GeV/n obtained from fragmentation of an Ar primary beam. The detector, designed to identify cosmic nuclei, features a Fused Silica radiator bar optically connected to a cylindrical mirror of the same material and an imaging focal plane of dimensions ∼4 cm×3 cm covered with a total of 1024 SiPM photosensors. Thanks to the outstanding performance of the SiPM arrays, the detector could be operated in photon counting mode as a fully digital device. The Cherenkov pattern was recorded together with the total number of detected photoelectrons increasing as Z 2 as a function of the atomic number Z of the beam particle. In this paper, we report on the characterization and test of the SiPM arrays and the performance of the Cherenkov prototype for the charge identification of the beam particles. [ABSTRACT FROM AUTHOR]

Four sulfide compounds' attenuation features of gamma-ray (Ag 2 ZnSnS 4 , Ag 2 ZnSnSe 4 , ZnS, and Ag 2 S) were described in this paper by a new software Phy-X/PSD. We calculated radiation attenuation parameters for the selected samples for a broad range of energies (0.015–15 MeV), including linear attenuation, the mean free path, the half-value layer, and total atomic and electronic cross-sections. The effective atomic number and the effective conductivity were also analyzed to investigate the radiation attenuation features. Also, the analyzed samples' buildup factors were studied. The samples' parameters were compared to materials frequently used to shield against radiation, including ferrite, chromite, barite, magnetite, and RS (253 G18, 360, 520) glass. Due to MFP and HVL values, Ag 2 S has better attenuation features than all the other samples utilized in the comparison. Fast neutron removal cross-sections (FNRCS) were also studied, and the best neutron attenuation composite among the samples under study, according to the FNRCS data, is Ag 2 S (0.116 cm−1). [ABSTRACT FROM AUTHOR]

A semi-analytical model is proposed for evaluating the electron stopping powers (ESPs) of material media including both elements and compounds in the energy range 1.0 eV–100 MeV. This paper reports details of our calculations using the effective atomic electron number, effective mean excitation energies of target atoms and realistic electron density distribution of the target atoms. This simple formula is capable of generating accurate cross-section for diverse systems. We present here only few simple cases. In comparison with other theoretical predictions, our calculated ESPs for elemental [C, Al, Cu, Pt, Au and Pb] and compound [H 2 O, C 5 H 5 N 5 O, GaAs, Bi 2 Sr 2 CaCu 2 O 8 , SiO 2 and ZnTe] media agree reasonably well with the experimental findings. [ABSTRACT FROM AUTHOR]

• Growth of large (1 in.) diameter boules of single crystal Cs 2 HfCl 6 and Cs 2 HfCl 4 Br 2. • Intrinsic scintillator crystals with simple cubic crystal structures. • Energy resolutions below 3.8% at 662 keV and good proportional responses to photon energies. This paper reports on successful growth and performance evaluation of two large diameter Cs 2 HfCl 6 (CHC) and Cs 2 HfCl 4 Br 2 (CHCB), both recently developed scintillator crystals. The discovery of Cs 2 HfCl 6 (CHC) as a scintillator has lately generated much interest in this material and its family, which belongs to the K 2 PtCl 6 cubic crystal structure. CHC is an intrinsic scintillator that is non-hygroscopic (slightly deliquescent, i.e., slightly moisture sensitive but does not deteriorate much when left in air), has no self-radioactivity, provides excellent energy resolution, and has excellent non-proportionality. CHC has a moderate density of 3.9 g/cm3 and an effective atomic number of 58. Reported in this paper are transparent crack-free single crystal CHC and CHCB boules of one inch in diameter, both grown using the vertical Bridgman method. Samples retrieved from the boules, sized ∅23 mm × 30 mm and ∅23 mm × 26 mm, respectively, are characterized for their optical and scintillation properties. Energy resolutions of 3.5% and 3.7% (FWHM) at 662 keV, respectively, are reported. Light yields of 23,000 ph/MeV and 20,000 ph/MeV have been calculated for the large diameter CHC and CHCB crystals, respectively. Results comparable to previously reported results for smaller crystals have been obtained. Studies on decay time, non-proportionality, as well as detector characterization are also reported. [ABSTRACT FROM AUTHOR]

Most techniques that are used for transmission imaging with ionizing radiation use X-rays, which have the advantage of providing quick, high-resolution images with a relatively small dose of radiation. However, they also have the disadvantage that their penetrating power can be limited in some forms of matter. This can make the discrimination of materials with a low atomic number particularly challenging. Of specific interest in this regard is the need to screen a diversity of manmade items that are heterogeneous and with the tendency to have many interfaces between components that can comprise a diversity of low-mass elements and compounds. These items usually have a compact geometry and a high density of components, which can make them less easy to be imaged quickly and effectively with X-rays. This limit of current screening technology necessitates further stages of examination reducing the ease with which this is done for manufacturing and quality assurance applications. The results presented in this paper demonstrate that, either via fast-neutron radiography or tomography, the potential exists to discern a variety of low-A compounds from one another. Via Monte Carlo simulations, it will be shown that fast-neutron radiography undertaken with a portable, isotopic radiation source (californium-252), absorption and scattering by the doped polymeric materials yields a degree of distinction from other substances. Considering these results, the state-of-the-art of the technique leading to the realization of a combined, real-time fast-neutron and γ -ray radiography system will also be presented, as well as the first experimental results. • This paper presents the potential of a real-time fast neutron and γ -ray imaging technique. • The technique would be suitable for the characterization of low-mass, solid-phase media. • Lithium Ion polymer can be discerned from some hazardous materials under neutron radiography. [ABSTRACT FROM AUTHOR]

Epidemiological studies indicate that clavicle fractures are predominant, particularly in men. Hydrated lime was found to be a suitable substance to mimic the bone composition. It is durable and has a good X-ray image intensity compared with that of a real bone. In contrast, silicone exhibits an X-ray diffraction spectrum similar to that of soft tissues. In this paper, phantoms with different sites of clavicle fractures were fabricated using hydrated lime, for education and quality assurance purposes. Phantoms with different pathologies of the left clavicle were fabricated via a multi-step technique. The clavicle phantoms were broken at different sites, representing most fractures reported in the literature. The clavicle phantom was radiographed along with the real clavicle bone using an X-ray machine (Definium 6000, General electric, 2009) with imaging parameters of 53 kV, 100 mA, and 1.2 mAs. This was performed to compare their structures and densities. The resulting mean grey values were 243.03, 248.97, and 253.53 for the real bone, bone fabricated using hydrated lime, and fabricated bone coated with silicone, respectively. This indicates a contrast of 0.02 between the real and fabricated bones and a contrast of 0.04 between the real and fabricated bones coated with silicone. Similar effective atomic number between bone and lime and low contrast values between the real bone and fabricated phantoms support the possibility of successful fabrication of clavicle phantoms using hydrated lime, for the purposes of education and quality assurance. • Clavicle phantoms were fabricated using hydrated lime. • Fabricated phantoms were broken at places to simulate fractures. • Fabricated phantoms along with a real clavicle bone were radiographed. • Low contrast between the grey values for the real bone and phantoms were recorded. [ABSTRACT FROM AUTHOR]

In this paper, a natural rubber (NR) with the addition of antimony oxide (Sb 2 O 3) has been developed for flexible radiation shielding materials. The composites of NR were prepared various amounts of Sb 2 O 3 concentrations. The mechanical properties including modulus at 100% elongation, tensile strength, elongation at break, hardness, and specific gravity of the NR composites were investigated. The gamma-ray shielding properties were measured in the energy range of 0.223 MeV–0.662 MeV by using the Compton scattering technique and compared with the theoretical values. From the results, it was found that the values of mass attenuation coefficient (μ m), effective atomic number (Z e f f ), and effective electron density (N e f f ) increased with an increase of the Sb 2 O 3 content. For the X-ray shielding properties, the mass attenuation coefficient (μ m) of NR composites was also higher with increasing Sb 2 O 3 concentration. Moreover, the half-value layer (HVL) of 20, 40, and 100 phr composites have been improved compared to the commercial windows, concrete, and red brick. These results reflected that the NR/Sb 2 O 3 composites are suitable for use as flexible radiation shielding materials. • New flexible shielding materials made from natural rubber (NR). • Natural rubber/Sb 2 O 3 enhanced shielding properties for gamma and X-ray. • Shielding properties show better than commercial windows, concrete, and red brick. • Natural rubber/Sb 2 O 3 composite is suitable for use as flexible radiation shielding materials. [ABSTRACT FROM AUTHOR]

Due to the increasing security needs, X-ray devices have started to be used more and more in security systems. Dual-energy X-ray devices are preferred to conventional ones since they enable Effective Atomic Number (Z e f f) estimation that cannot be provided by traditional devices, which use density-based segmentation. In this paper, pure material samples are used to obtain system characteristics. Linear mass attenuation coefficients (μ) of the materials can be calculated by using two leveled images, and these coefficients provide information about the Z e f f of substances. After that, they can be classified as organic and inorganic via the effective atomic number method and explicitly identified. As well as this, organic explosives can be detected thanks to this simple and effective approach. [ABSTRACT FROM AUTHOR]

In this paper, the structural, thermal and nuclear radiation shielding properties of a new Lead–Lithium-Phosphate glass system with different amount lithium oxide were studied. The glass samples were prepared by the conventional melt-quenching method and they having compositions (75-x) P 2 O 5 – 25PbO- xLi 2 O with x = 0, 5, 10, 15, 20 mol%. The influence of Li 2 O content on the structural, thermal, radiation shielding properties, and other related properties of the synthesized glasses was studied. The structural properties were investigated using XRD and Raman spectroscopy. The glass transition temperature T g and crystallization onset temperature T x are estimated from the DSC profile. The GEANT4 Monte Carlo simulation code was used to estimate thermal neutron attenuation coefficient (μ nt) in a wide neutron energy range of 0.0253–100 eV and ParShield code was used to calculate effective fast neutrons removal cross-section (∑R). The gamma-ray attenuation parameters such as mass attenuation coefficients (μ m), effective atomic number (Z eff), effective electron density (N eff) and half-value layer (HVL) have been computed by using ParShield code in the energy range of 0.103–1.33 MeV. However, the total mass stopping power (MSP) and projected range (PR) values have been estimated for alpha particles (4He2+) and Triton particle (3H) by using SRIM in the energy range of 0.1–10 MeV. [ABSTRACT FROM AUTHOR]

In this paper, a summary of experimental data published in the period of time between 1955 to february-2016 was presented in a tabular form for L i subshell fluorescence yields ( ω L1 , ω L2 and ω L3 ) taken from different sources. First, a critical examination of these data using the weighted average values ω Li - W was presented. Then, an interpolation using the famous analytical function ( ω Li - W / ( 1 − ω Li - W ) ) 1 / 4 vs the atomic number Z was proformed to deduce a new empirical L i subshell fluorescence yields for elements in the range 40≤Z≤96 for ω L1 and ω L2 and 23≤Z≤96 for ω L3 . At last, our calculated empirical L i subshell fluorescence yields have been compared with other theoretical and empirical values reported in the literature. [ABSTRACT FROM AUTHOR]

Recent calculations (Mahmoud and Lugli, 2013, [21] ) of gold leads sandwiching carbon chains which are separated by diphenyl–dimethyl demonstrated that the negative differential resistance (NDR) effect appears only for “odd” numbers of carbon atoms. In this paper, according to a first-principles study based on non-equilibrium Green's function combining density functional theory, we find that the NDR effect appears both for “odd” and for “even” numbers of carbon atoms when the chains are doped by nitrogen atom. Our calculations remove the restriction of “odd/even” chains for the NDR effect, which may promise the potential applications of carbon chains in the nano-scale or molecular devices in the future. [ABSTRACT FROM AUTHOR]

In this paper, multiple scattering of 137 Cs gamma photons from composite materials is studied experimentally. Photons scattered in backward direction of 90° to the incident beam are detected by a NaI (Tl) detector. Single scattered events are reconstructed analytically to extract multiple scattered photons from the measured spectrum. We observe that for an increase in target thickness, there is an increase in multiple backscattered photons. After a particular thickness called as saturation thickness, multiple backscattered photons becomes almost a constant. The saturation thickness of the multiple scattered photons is used to assign effective atomic number for HDPE, UHMW, Nylon, Bakelite, Glass-epoxy, local wood ( Hopea parviflora ) and Portland Cement (grade 43). Experimental results are compared with Monte Carlo simulation. The ratio of single scattering events to multiple scattering events decreases for an increase in target thickness. [ABSTRACT FROM AUTHOR]

In this paper we discussed the optical and radiation shielding properties are strongly dependent on the physical parameter viz; (i) interionic interaction parameter, A(n 0) , (ii) coordination number, CN, (iii) single bond strength (B M-O) and (i v) optical basicity, Λ(n 0) of glasses (95-x) TeO 2 – 5Ta 2 O 5 -xBi 2 O 3) where x = 5, 10, 15, and 20 in mol %. Furthermore, the various optical parameters viz ; linear refractive index, optical absorption coefficient, optical energy gap, Urbach energy, density, oxygen molar volume, nonlinear refractive index, molar refraction, oxygen packing density, reflection loss, molar electronic polarizability of fabricated glasses were estimated. The shielding parameters viz; mass attenuation coefficient, linear attenuation coefficient, half value layer, mean free path, tenth value layer, effective electron number, effective atomic number, atomic and electronic cross sections have been calculated of fabricated glass against a wide range of ionizing energy ranging from 0.015 to 15 MeV. Results showed that increasing the concentration of Bi 2 O 5 from 5 to 20% led to an increase in the linear attenuation coefficient (LAC). Compared with commercially available standards and reported some tellurite glasses to contain Bi 2 O 3 in the literature, the investigated material showed superior performance at energies ranging between 800 keV and 10 MeV. Radiation protection efficiency (PRE) of 70TeO 2 –5Ta 2 O 5 –20Bi 2 O 3 glass varied from 99.9 to 83.9% at low energy from 15 to 200 KeV. Therefore, this glass has a high density, refractive index, and a superior capability of radiation shielding materials at low energy. • Increasing Bi 2 O 3 into the glass structure enhances optical and radiation protection efficiency (PRE%) characteristics. • The TTB1 glass has the lowest value of E o p t = 2.71 eV and TTB4 has the lowest value of Δ E = 0.41 eV. • The prepared glass system can be used for radiation shielding in medical applications at low energy from 15 to 200 keV. • The RPE% of the fabricated glasses decreased from 100 to 72.75% with the photon energy increased from 15 to 200 keV. [ABSTRACT FROM AUTHOR]

A recently published detailed and exhaustive paper on cross-sections for ionisation induced by keV electrons clearly shows that electron phenomena occurring in parallel with X-ray processes may have been dramatically overlooked for many years, mainly when low atomic number species are involved since, in these cases, the fluorescence coefficient is smaller than the Auger yield. An immediate problem is encountered while attempting to tackle the issue. Accounting for electron phenomena requires the knowledge of the stopping power of electrons within, at least, a reasonably small error. Still, the Bethe formula for stopping powers is known to not be valid for electron energies below 30 keV, and its use leads to values far off experimental ones. Recently, a few authors have addressed this problem and both detailed tables of electron stopping powers for various atomic species and attempts to simplify the calculations, have emerged. Nevertheless, its implementation in software routines to efficiently calculate keV electron effects in materials quickly becomes a bit cumbersome. Following a procedure already used to establish efficient methods to calculate ionisation cross-sections by protons and alpha particles, it became clear that a simple polynomial approximation could be set, which allows retrieving the electronic stopping powers with errors of less than 20% for energies above 500 eV and less than 50% for energies between 50 eV and 500 eV. In this work, we present this approximation which, based on just six parameters, allows to recover electron stopping power values that are less than 20% different from recently published experimentally validated tabulated data. [ABSTRACT FROM AUTHOR]

In this paper, the interaction of gamma rays with some shielding materials has been studied. The total mass attenuation coefficient ( μ t ) for eight shielding materials has been calculated by using WinXCOM program in the energy range from 1 keV to 100 GeV. Also, the effective atomic number ( Z eff ) and the effective electron density ( N eff ) were calculated using the values of the total mass attenuation coefficient. The dependence of these parameters on the incident photon energy and the chemical composition has been examined. [ABSTRACT FROM AUTHOR]

In high-energy heavy-ion collisions, partonic collectivity is evidenced by the constituent quark number scaling of elliptic flow anisotropy for identified hadrons. A breaking of this scaling and dominance of baryonic interactions is found for identified hadron collective flow measurements in s NN = 3 GeV Au+Au collisions. In this paper, we report measurements of the first- and second-order azimuthal anisotropic parameters, v 1 and v 2 , of light nuclei (d , t , 3He, 4He) produced in s NN = 3 GeV Au+Au collisions at the STAR experiment. An atomic mass number scaling is found in the measured v 1 slopes of light nuclei at mid-rapidity. For the measured v 2 magnitude, a strong rapidity dependence is observed. Unlike v 2 at higher collision energies, the v 2 values at mid-rapidity for all light nuclei are negative and no scaling is observed with the atomic mass number. Calculations by the Jet AA Microscopic Transport Model (JAM), with baryonic mean-field plus nucleon coalescence, are in good agreement with our observations, implying baryonic interactions dominate the collective dynamics in 3 GeV Au+Au collisions at RHIC. [ABSTRACT FROM AUTHOR]

Dual energy based X-Ray baggage inspection system (XBIS) are widely deployed for the detection of objects for security applications. We have presented a comprehensive approach for processing of the raw image data obtained from X-ray detectors for material classification and for pseudo-color representation in three classes of materials. Monte Carlo simulation studies were carried out to understand the variation of R-values with atomic number of materials. Since the R-values show dependence on the thickness of materials, an overlap of R values has been observed for materials of different atomic number. Hence, for material classification, an algorithm was developed to process the raw image data obtained from the detector system hardware using test objects. The dual energy data, i.e. low energy and high energy data obtained was integrated as one data using a wavelet based data fusion algorithm. The fused image was represented as a pseudo-colored image to indicate material classification of various objects. Standard Test Piece image and other images obtained through various processing steps were analyzed for accuracy of material classification. The data processing methods presented in this paper show improved accuracy and speed for material classification of objects in XBIS. • Data processing techniques from acquired detector data to the display of pseudo colored images. • DWT image fusion technique, high information transfer from LE and HE has been achieved. • An improved material discrimination algorithm for dual energy XBIS has been demonstrated. • The outcome of algorithm shown to prove the good accuracy with cluster of objects. [ABSTRACT FROM AUTHOR]