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In this paper, the gamma radiation shielding properties of S-TV/TiX glasses are investigated at different photon energies using data from FLUKA simulations and the XCOM library. Three samples of TV screen glass (S-TV) doped with TiO2 were prepared using cold isostatic pressing. The samples were designated as S-TV, S-TV/Ti10, and S-TV/Ti20 for TiO2 concentrations of 0 wt.%, 10 wt.%, and 20 wt.%, respectively. The gamma radiation transmission data for the samples obtained from FLUKA simulations and the XCOM database were used to compute the mass attenuation coefficient (µ/ρ) of the S-TV/TiX samples. Other photon interaction parameters, including the half-value layer (HVL ), mean free path (λ ), effective atomic number (Z eff ), electron density ( N eff ), specific gamma constants (Γ ), dose rate ( D r ), equivalent atomic number ( Z eq ), exposure (EBF ), and energy absorption (EABF ) buildup factors were calculated from the µ/ρ data based on standard expressions and procedures. The µ/ρ values were in the range of 0.02442–12.57505 cm2/g, 0.02438–13.54632 cm2/g, and 0.02434–14.50959 cm2/g for S-TV, S-TV/Ti10, and S-TV/Ti20, respectively. Based on the obtained HVLs, it was observed that as the TiO2 content increased, the glass thickness required to attenuate photons also increased. Analysis of the effective atomic number and electron density showed that the glass sample with lower TiO2 content exhibited more electron interaction and hence absorbed more photons. The photon scattering potential of the glasses varied with glass composition and gamma energy. The study further showed that the trend of photon scattering ability among the glasses fluctuated at different energies. However, at 1.5 MeV, the glasses with lower TiO2 content exhibited higher photon buildup factors. In comparison with standard radiation shielding materials such as concrete and glasses, TiO2-doped S-TV glasses have better gamma absorption capacity and are therefore suitable for gamma-shielding applications, especially for low (keV) energies. [ABSTRACT FROM AUTHOR]

This paper focuses on examining the radiation shielding features of seven boro-tellurite glasses in the form of TeO2–B2O3–SrCl2–LiF–Bi2O3. Gamma rays and neutrons shielding features of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), mean free path (MFP), effective atomic number (Zeff), and removal cross section (∑R). The μ/ρ values of the present glasses were simulated by Geant4 Monte Carlo simulations over an extended energy range of 0.015 − 20 MeV and then the generated data were verified using the calculated values of WinXCOM software. Additionally, geometric progression (G–P) method was used to estimate gamma ray exposure buildup factor (EBF) for the prepared glasses. It is noted that μ/ρ and Zeff values increase, while MFP and HVL values decrease as TeO2 content increases in the glass sample. The EBF values would be useful to design or develop the present glasses for gamma shielding applications. Results reveal that the present glasses have good capability for gamma rays shielding compared with some commercial radiation shielding materials. [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]

Studies of bioactive glasses give an advanced roadbook to realize radiation applications in nuclear medicine and other medical applications. This paper aims to investigate the gamma ray interaction parameters of the PbCl2–SnCl2–P2O5 glass system. The mass attenuation coefficients (μm) of the selected bioactive glasses have been obtained using XCOM and dosimetry Phy-X/PSD programs in the photon energy range 10–150 keV and also correlated with those simulated through MCNP5 code. The other parameters, such as the effective atomic number (Zeff), electron density (Ne), and mean free path (MFP), tenth-value layer (TVL), and half-value layer (HVL) values have also been computed. Among all the selected bioactive glasses, the S4 bioactive glass has the lowest MFP, HVL, and TVL, showing that it is highly effective in absorbing gamma rays. The values of MFP of all samples (S1–S8) are also compared to the RS 253G18 and RS 360 commercial glasses at energy 150 keV. The fast neutron removal cross-sections have been obtained to study the fast neutron absorption behavior with the selected bioactive glasses. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the gamma radiation shielding properties of P2O5-SiO2-K2O-MgO-CaO-MoO3 glasses. The mass attenuation coefficients (µm) have been computed via Photon Shielding and Dosimetry (Phy-X/PSD) software in the energy range 0.015-15 MeV. The other shielding factors are also computed as the effective atomic number (Zeff), electron density (Ne), and mean free path (MFP) values, exposure (EBF) and energy absorption (EABF) buildup factors for a penetration depths 20 mfp. The values of the shielding parameters are strongly dependent on energy and chemical composition. The PSKMCM6 possesses the lowest value of MFP and highest value of µm and Zeff, among the glasses. The glass sample PSKMCM6 has minimum value of EBF and EABF as compared to other samples. [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]

Abstract: DEXA (dual-energy X-ray absorption) is widely used in airport scanners, industrial scanners and bone densitometers. DEXA determines the properties of materials by measuring the absorption differences of X-rays from a bremsstrahlung tube source with and without filtering. Filtering creates a beam with a higher mean energy, which causes lower material absorption. The absorption difference between measurements (those with a filter subtracted from those without a filter) is a positive number that increases with the effective atomic number of the material. In this paper, the concept of using a filter to create a dual beam and an absorption difference in materials is applied to radiation from a 252Cf source, called NEUDEG (neutron and dual-energy gamma absorption). NEUDEG includes absorptions for fast neutrons as well as the dual photon beams and thus an incentive for developing the method is that, unlike DEXA, it is inherently sensitive to the hydrogen content of materials. In this paper, a model for the absorption difference and absorption sum in NEUDEG is presented using the combined gamma ray and fast neutron mass attenuation coefficients. Absorption differences can be either positive or negative in NEUDEG, increasing with increases in the effective atomic number and decreasing with increases in the hydrogen content. Sample sets of absorption difference curves are calculated for materials with typical gamma-ray and fast neutron mass attenuation coefficients. The model, which uses tabulated mass attenuated coefficients, agrees with experimental data for porcelain tiles and polyethylene sheets. The effects of “beam hardening” are also investigated. [Copyright &y& Elsevier]

Photoelectric absorption is an interaction in which an incoming gamma ray virtually transfers all of its energy to an atomic electron, usually the most tightly bound K-shell electron of an atom. This paper uses the Win XCOM computer code as a reference base. We found analytical photoelectric attenuation coefficients for researchers using the Monte Carlo simulation program for Z∈ [1; 100] and E∈[10 keV; 3 MeV]. We define a photoelectric effect operator and coefficient operators and a series for photoelectric absorption. We have calculated two polynomial coefficient operators for use with XCOM for photoelectric absorption. We determined 14 energies and atomic number limits for elements, and we find that they are accurate limits of photoelectric absorption for fitting with XCOM. [ABSTRACT FROM PUBLISHER]

The photoelectric factor (PEF) is an important well-logging tool to distinguish between different types of reservoir rocks because PEF measurement is sensitive to elements with high atomic numbers. Furthermore, the ratio of rock minerals could be determined by combining PEF log with other well logs. However, PEF logs could be missing in some cases such as in old well logs and wells drilled with barite-based mud. Therefore, developing models for estimating missing PEF logs is essential in those circumstances. In this work, we developed various machine learning models to predict PEF values using the following well logs as inputs: bulk density (RHOB), neutron porosity (NPHI), gamma ray (GR), compressional and shear velocity. The predictions of PEF values using adaptive-network-fuzzy inference system (ANFIS) and artificial neural network (ANN) models have errors of about 16% and 14% average absolute percentage error (AAPE) in the testing dataset, respectively. Thus, a different approach was proposed that is based on the concept of automated machine learning. It works by automatically searching for the optimal model type and optimizes its hyperparameters for the dataset under investigation. This approach selected a Gaussian process regression (GPR) model for the accurate estimation of PEF values. The developed GPR model decreases the AAPE of the predicted PEF values in the testing dataset to about 10% AAPE. This error could be further decreased to about 2% by modeling the potential noise in the measurements using the GPR model. [ABSTRACT FROM AUTHOR]

This paper revises the use of polymer nanocomposites to attenuate high-energy electromagnetic radiation (HE-EMR), such as gamma radiation. As known, high-energy radiation produces drastic damage not only in facilities or electronic devices but also to life and the environment. Among the different approaches to attenuate the HE-EMR, we consider the use of compounds with a high atomic number (Z), such as lead, but as known, lead is toxic. Therefore, different works have considered low-toxicity post-transitional metal-based compounds, such as bismuth. Additionally, nanosized particles have shown higher performance to attenuate HE-EMR than those that are micro-sized. On the other hand, materials with π-conjugated systems can also play a role in spreading the energy of electrons ejected as a consequence of the interaction of HE-EMR with matter, preventing the ionization and bond scission of polymers. The different effects produced by the interactions of the matter with HE-EMR are revised. The increase of the shielding properties of lightweight, flexible, and versatile materials such as polymer-based materials can be a contribution for developing technologies to obtain more efficient materials for preventing the damage produced for the HE-EMR in different industries where it is found. [ABSTRACT FROM AUTHOR]

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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]

The gamma ray, neutron, and electron radiation interaction parameters were calculated for some topological insulating (TI) materials such as Sb2Te3, Bi2Se3, Bi2Te2Se and Bi2Te3 at various energies. The gamma ray interaction parameters such as mass attenuation coefficient, half value layer, tenth value layer, effective atomic number, equivalent atomic number, exposure buildup factor, and energy absorption buildup factor were calculated in the energy range of 0.015–15 MeV at penetration depths of 1–40 mfp by using the five-parameter Geometric Progression (G-P) fitting approximation method. The buildup factors were found to be dependent on the energy of the incident photon, penetration depth, and material elemental composition, and they were also found to be higher for Sb2Te3 than for other TI materials throughout the energy region of investigation. The neutron interaction parameters, such as fast neutron removal cross section, were calculated for the selected topological insulator materials using Phy-X/PSD software and found to be higher for Bi2Te3 than for the other three materials. The electron stopping power values were calculated for the selected topological insulator materials in the energy range of 0.01 MeV to 1000 MeV using the ESTAR program. It was found that the stopping power values decreased slowly with increasing electron energy in the lower energy region, remained almost constant in the medium energy region, and increased rapidly in the higher energy region. [ABSTRACT FROM AUTHOR]

Nuclear radiation shielding parameters for glass samples composed of 20 mol.% Li2O-40 mol.% ZnO-40 mol.% P2O5: x wt.% Yb2O3 (x = 0, 0.2, 0.4, 0.6, 0.8, 1, 2) were evaluated. The samples were synthesized using the melt-quenching technique. The prepared samples were encoded Yb0.0, Yb0.2, Yb0.4, Yb0.6, Yb0.8, Yb1 and Yb2 according to the Yb2O3 content. X-ray diffraction (XRD) reveals that all the prepared samples were amorphous. The gamma ray shielding parameters such as mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half value layer (HVL) and mean free path (MFP) were obtained using Phy-X/PSD and XCOM software programs. The atomic cross section (ACS), electronic cross section (ECS), effective atomic number (Zeff), and electron density (Neff) were evaluated, as well as exposure buildup factor (EBF) and energy absorption buildup factor (EABF). The MAC values were found to be 26.304–31.872 cm2/g for Yb0.0–Yb2, respectively. The HVL and MFP values were found to be (0.008–0.007 cm) and (0.012–0.010 cm) for Yb0.0–Yb2, respectively. The ACS and ECS values were found to be (9.912 × 10−21 cm2/g) up to 13.06 × 10−21 cm2/g) and (3.990 × 10−23 up to 4.900 × 10−23 cm2/g) for Yb0.0–Yb2, respectively. The Zeff and Neff values were found to be (24.83–26.64) and (6.59 × 1023 up to 6.50 × 1023 electrons/g) for Yb0.0–Yb2, respectively. The results showed that the addition of Yb2O3 improves gamma-ray shielding properties of the glass. On the other hand, adding Yb2O3 to the prepared glass leads to a decrease in the removal cross section for fast neutrons (ƩR) from 0.103 to 0.096 cm for Yb0.0–Yb2, respectively. The gamma-ray shielding parameters for the present samples were compared with commercial concrete and glass used as gamma ray shields. [ABSTRACT FROM AUTHOR]

In this paper, the effective atomic numbers (Zeff) and electron densities (Neff) representing interaction of gamma rays with oxides of lanthanides were studied. The effective atomic numbers for photon energyabsorption (ZPEAeff), photon interaction (ZPIeff), relative to air ZReff, the effective electron densities for photon energy-absorption (NPEAeff) and photon interaction (NPIeff) were calculated using the values of the mass attenuation and energy absorption coefficients. In the continuous energy region, agreements and disagreements were observed between photon interaction and photon energy-absorption for Zeffs and Neffs of compounds in different energy regions. In addition, absorption edge effects on Zeffs leading more than a single value of Zeff at a specific energy have been discussed for the given compounds. Comparisons with experiments wherever possible have been carried out for calculated values of Zeff and Neff. [ABSTRACT FROM AUTHOR]

In this study, we synthesized binary germanate glasses with compositions of GeO2 – Bi2O3, GeO2 – PbF2, and GeO2 – V2O5. The traditional melt-quenching method was used for glass synthesis. The radiation shielding properties of the synthesized samples were calculated theoretically and measured experimentally as well. A narrow-beam transmission geometry, which uses a NaI(Tl) detector, was employed to measure linear attenuation coefficient, mass attenuation coefficient, half-value layer, and effective atomic number values of the glasses at gamma-ray energies of 662, 1173, and 1332 keV and, 137Cs, and 60Co radioactive point sources were used to produce gamma-ray photons of these energies. Additionally, all the above parameters were also calculated theoretically using the WinXCOM software in the 0.015-15 MeV energy range to confirm the accuracy of the measurements. A good agreement between theoretical and experimental findings was observed. It was also found that the increase in the concentrations of Bi2O3, PbF2, and V2O5 network modifiers improved the radiation shielding capacity of synthesized germanate glasses. The results revealed that the GeBi30 glass has superior shielding properties among the synthesized germanate glasses. [ABSTRACT FROM AUTHOR]

Gamma rays is widely used in modern science and technology, but it may cause health damage to practitioners. In the present study, natural composites based on leather and high-Z elements (atomic number ≥ 56) were fabricated and used as gamma rays shielding materials. These shielding materials were prepared by coating rare earth nanoparticles (Er2O3 or La2O3) onto the surface of natural leather, which was first impregnated with Bi3+ and Ba2+. Results show that the attenuation efficiency of the prepared Er1.31Bi5.46-NL (1.31 and 5.46 mmol cm−3 loaded elements) with thickness of 3.2 mm was 61.57% for incident rays at 121.78 keV (152Eu) and reached 96.4% in the incident of 59.5 keV (241Am), which is comparable to that of 0.25-mm lead plate (54.54 mmol cm−3). In addition, these natural-leather-based shielding materials exhibited low density (approximately 1/10 of Pb), high strength and wearable behaviors. [ABSTRACT FROM AUTHOR]

This paper evaluates the γ-radiation shielding traits of some new types of borate glasses of composition (70–x)B 2 O 3 –10Bi 2 O 3 –10BaO–10CdO–xPbO (where 0 ≤ x ≤ 20 mol%) prepared using melt quenching method. As-quenched samples were characterized to determine the effects of various PbO contents on their γ-radiation shielding properties. XRD patterns of the samples verified their amorphous nature. The Phy-X and XCOM was used to compute the mass attenuation coefficients of the glasses and then compared with the experimental data. The γ-radiation shielding performance of the proposed glasses were evaluated in terms of diverse attenuation parameters like mean free path, half and tenth value layer, atomic cross-section, electronic cross-section, effective atomic number and effective electron density. The γ-radiation shielding performance of the glasses were significantly improved with the increase of PbO contents. This new borate glass system is established to be advantageous for the radiation shielding applications. • The borate glass samples with different PbO content were prepared by the standard melt-quenching method. • The μ/ρ values of the glasses were increased with the increase of the PbO content. • The relatively higher Zeff at lower energies due to the dominance of PE effect. • Promising HVT and TVL achieved with the new prepared glasses. • The proposed glass improves the efficiency of IR shielding material. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to develop a method to correct the absorbed radiation (the mass attenuation coefficient curve) in low energy (E <30keV) applied to a biological matrix based on the Rayleigh to Compton scattering ratio and the effective atomic number. For calibration, scattering measurements were performed on standard samples of radiation produced by a gamma-ray source of 241Am (59.54keV) also applied to certified biological samples of milk powder, hay powder and bovine liver (NIST 1557B). In addition, six methods of effective atomic number determination were used as described in literature to determinate the Rayleigh to Compton scattering ratio (R/C), in order to calculate the mass attenuation coefficient. The results obtained by the proposed method were compared with those obtained using the transmission method. The experimental results were in good agreement with transmission values suggesting that the method to correct radiation absorption presented in this paper is adequate for biological samples. [Copyright &y& Elsevier]

The paper describes the effect of high effective atomic number (Z eff) materials loading in polystyrene based thin-film Plastic Scintillators (PS). Thin plastic scintillator sheets have been loaded with high Z materials such as BaFBr:Eu, Gd 2 O 2 S:Tb, Gd 2 O 3 , BaF 2 , CeO 2 and Bi 2 O 3. Polystyrene based PS sheets of 250 ± 50 μ m thickness have been prepared by dissolving predetermined quantities of polystyrene, 2,5-Diphenyloxazole (PPO) and 1,4-bis(5-phenyl-2-oxazolyl) benzene (POPOP) in the p-xylene solvent. High Z eff material powders of 23 μ m size are mixed in the plastic scintillator solution and coated over the cellulose acetate-based transparency sheets. The dried films are peeled off, and their photoluminescence, radioluminescence, pulse height spectrum and response to alpha, beta, gamma and neutron radiations are studied by adopting suitable methods. The high Z eff materials for loading in PS are selected based on their physical properties like refractive index, bandgap, Z eff , Photoluminescence (PL) properties. While the composite scintillator loaded with 14.3 wt% of BaFBr:Eu2+ showed significant increase compare to other high Z materials. The loading concentration has been optimized as 14.3 wt% from the BaFBr:Eu2+ studies. Most of the composite scintillators showed improvement in radioluminescence and pulse height spectra for different radiations. • Polystyrene based thin plastic scintillator have been prepared by solvent-based fabrication method. • Thin composite plastic scintillator are studied with high Z eff material loading. • High Z eff material loaded composite scintillators showed enhanced response to radiation. • BaFBr:Eu loaded composite PS has shown the best promising result. [ABSTRACT FROM AUTHOR]

This study aimed to perform an extensive characterization of a 74.75TeO2–0.25V2O5–(25 − x)B2O3-xNd2O3 glass system with (x = 0, 0.5, 1.0, and 1.5 mol%) for radiation shielding properties. Linear and mass attenuation coefficients were determined using Phy-X PSD software and compared with the simulation using Monte Carlo software MCNPX (version 2.7.0). Half value layer, mean free path, tenth value layer, effective atomic number, exposure buildup factor, and energy absorption buildup factors of VTBNd0.0, VTBNd0.5, VTBNd1.0, and VTBNd1.5 glasses were determined, respectively. The results showed that boron (III) oxide and neodymium (III) oxide substitution has an obvious impact on the gamma ray attenuation properties of the studied glasses. It can be concluded that the VTBNd1.5 sample with the highest content of neodymium (III) oxide (1.5 mol%) is the superior sample for shielding of gamma radiation in the investigated energy range. [ABSTRACT FROM AUTHOR]

We report on the measurements of the spectra of gamma radiation generated by 855 MeV electrons in bent silicon and germanium crystals at MAMI (MAinzer MIkrotron). The crystals were 15 μ m thick along the beam direction to ensure high deflection efficiency. Their (111) crystalline planes were bent by means of a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature. In such a way it was possible to investigate the radiation emitted under planar channeling and volume reflection as a function of the curvature of the crystalline planes. We showed that, using volume reflection, intense gamma radiation can be produced – with intensity comparable to that obtained in channeling but with higher angular acceptance. We studied the trade-off between radiation intensity and angular acceptance at different values of the crystal curvature. The measurements of radiation spectra have been carried out for the first time in bent germanium crystals. In particular, the intensity of radiation in the germanium crystal is higher than in the silicon one due to the higher atomic number, which is important for the development of the X-ray and gamma radiation sources based on higher-Z deformed crystals, such as crystalline undulators. [ABSTRACT FROM AUTHOR]

We employed measurement of the Pockels electro-optic effect to study the electric field and space charge dynamics in semi-insulating CdTe doped with indium. We performed measurements of time and temperature dependence of the electric field. The polarization due to space charge build-up decreases with increasing temperature. Increase of temperature, therefore, leads to de-polarization in CdTe:In detectors which are opposite to the CdTe:Cl samples studied to date. We have shown that the thermally activated depolarization cannot be explained by the conventional model used for the description of space charge formation so far and an alternative model involving a recombination level was suggested and successfully used. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a biodegradable organic acid of polymeric chain that has as chemical structure the monomer C 3 H 4 O 2 and it is one of the most used materials in rapid prototyping among 3D printers. Due to the ease of manufacturing PLA parts and because of its low atomic number, PLA can be used as holder to radiation source and detectors to establish fixed geometries in experiments using gamma radiation, hence the importance in knowing more about PLA characteristics. In this way, the novelty of this paper is to determine the mass attenuation coefficient of 3D printed PLA samples using gamma densitometry. A mathematical model was developed using MCNPX code and consisted of a PLA sample, a NaI(Tl) detector and gamma rays of 661.6 keV as radiation source (narrow beam). The mathematical model was experimentally validated using the same geometry and a lead collimator. Besides that, PLA weight fractions and density were also determined in order to use this information as input data in the MCNPX code. The obtained mass attenuation coefficients were in good agreement with the NIST theoretical reference value, presenting relative errors of 0.99% (MCNPX) and 2.00% (experimental). The proposed methodology was repeated replacing PLA for aluminum samples and comparing its results with NIST. In addition, the mass attenuation coefficient for some polymers was calculated using this model aiming to validate the geometry developed with MCNPX code. • Simulation of mass attenuation coefficients using MCNPX code. • Absorber material are 3D printed polylactic acid samples. • Experimental validation of the methodology using gamma densitometry. • Simulation of others absorber materials. [ABSTRACT FROM AUTHOR]

This paper focuses on the role of antimony oxide (up to 15 wt%) in the physical, structural, optical, and radiation attenuating characteristics of boro-bismuth glasses within B 2 O 3 -20Bi 2 O 3 - 20Na 2 O 2 - Sb 2 O 3 system. This glass system was prepared by melting at 1250°C and quenching into water. The physical properties were studied by measuring the density, molar volume, and x-ray diffraction for the prepared glass system. The structural features were investigated by determining packing density, passion ratio, oxygen packing density, and oxygen molar volume. The optical attributes were explored by evaluating bandgap, Urbach energy, refractive index, and other related parameters such as dielectric constant, reflection loss, molar polarizability, molar refractivity, optical dielectric constant, optical electronegativity, electron polarizability, optical basicity, metallization, and cut-off wavelength. On the other hand, the shielding properties of the prepared glasses were studied against different types of radiation such as gamma, electron, proton, and neutron beams. The radiation studies were carried out by utilizing Geant4 simulations and the newly developed Phy-X/PSD program. The radiation-shielding characteristics of the present samples were examined in terms of mass attenuation coefficient, stopping power, half value layer, removal cross section, mean free path, and effective atomic number of gamma, electron, and proton beams. The results showed that antimony oxide content had an important influence on the shielding ability against all of the types of radiations. Additionally, the obtained results were compared with those of standard radiation shields. It can be concluded that the present glasses have a promising future to be used as radiation shielding material, wherein the antimony oxide concentration can be balanced according to the desired application. [ABSTRACT FROM AUTHOR]

Luminescence and scintillation properties of Eu2+- and Ce3+-doped TlSr2Cl5 crystals are reported for large effective atomic number (Zeff = 63.7) that have potential applications in X-ray and gamma ray detection. We have previously developed TlSr2Cl5 crystalline scintillators. To improve the scintillation properties of TlSr2Cl5, Ce3+ and Eu2+ were doped into the crystals in this study. The scintillation emission bands of Eu2+-doped TlSr2Cl5 were observed at 420 nm and those for Ce3+-doped TlSr2Cl5 were observed at 380, 450, and 500 nm. Band peaks at 450 and 500 nm were similar to those of undoped TlSr2Cl5, which are characteristic of self-activated thallium-based chloride crystals. The light yields of Ce3+- and Eu2+-doped TlSr2Cl5 were estimated to be approximately 16,000 and 21,000 photons/MeV, respectively. The light yield of Eu2+-doped TlSr2Cl5 is higher than that of undoped TlSr2Cl5 crystals (19,000 photons/MeV). It was suggested that Eu2+ is more suitable dopant for TlSr2Cl5 than Ce3+. The higher light yield of Eu2+-doped TlSr2Cl5 is due to the emissions by Eu2+ ions, which makes it easier to distinguish peaks from noise and improve the energy resolution. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC) loaded with different filler levels equal to 0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 2.5, 3.5 and 5.0 wt% (weight percent) of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O or BNP) were prepared by dispersion of filler in PC solution, followed by casting. The values of mass attenuation coefficient (μm), effective atomic number (Zeff), effective electron density (Nel), half value layer (HVL) thickness, tenth value layer (TVL) thickness and photon mean free path (MFP or λ) were determined for specific gamma photon energies ranging from 303 up to 1332 keV, both computationally and experimentally. Considerable variation in the radiation attenuation parameters was observed, which is mainly dependent on the energy of incident gamma ray photon and the concentration of BNP incorporated as filler within the PC matrix. Values of the experimentally determined parameters like μm, Zeff and Nel were compared with the computationally estimated values, and they are found to be in good agreement. The results are discussed, taking into consideration our understanding of the interaction of gamma radiation with matter. [ABSTRACT FROM AUTHOR]

This article reports the characteristics of thermoluminescence (TL) dosimeter of dysprosium doped strontium borate glass for NaO, Li2O, and CaO modifiers imposed by 10–90 Gy dose of 60Co gamma ray irradiation. The different elements are (70.0 – x) B2O3–20SrO–10NaO–xDy2O3, 10Li2O–20SrO–(70 – x)B2O3–(x)Dy2O3 and 10CaO–20SrO–(70.0 – x)B2O3–(x)Dy2O3 (x = 0, 0.10, 0.30, 0.50, 0.70 mol %). The glass was formed by melt quenching method and the ranges of Dy2O3 were 0.0 to 0.7 mol %. Calcium strontium borate doped with 0.3 mol % Dy2O3 shows very good linearity on dose response and gives an excellent sensitivity at 50 Gy dose of 60Co gamma ray irradiation. The samples N1, L1, C3 were completely amorphous. The optimums anneal temperature, time, concentration of Dy2O3 and heating rate were investigated for glass samples N1, L1, C3. The systematic characteristics of glow curve, TL intensity, reproducibility, sensitivity, kinetic parameters and effective atomic number were studied for three selected samples. All samples show the maximum peak from 154–200°C temperatures. [ABSTRACT FROM AUTHOR]

In this paper, we report the effective atomic number of some H, C, N and O based sugars and amino acids. These have been determined by using a handy expression which is based on the theoretical angle integrated small angle (coherent+incoherent) scattering cross sections of seven elements of Z ≤ 13 in four angular ranges of (0–4°), (0–6°), (0–8°) and (0–10°)for 241 Am (59.54 keV) and 137 Cs (661.6 keV) gamma rays. The theoretical scattering cross sections were computed by a suitable numerical integration of the atomic form factor and incoherent scattering function compilations of Hubbell et al. (1975) which make use of the non-relativistic Hartree–Fock (NRHF) model for the atomic charge distribution of the elements in the angular ranges of interest. The angle integrated small angle scattering cross sections of the H, C, N and O based sugars and amino acids measured by a new method reported recently by the authors were used in the handy expression to derive their effective atomic number. The results are compared with the other available data and discussed. Possible conclusions are drawn based on the present study. [ABSTRACT FROM AUTHOR]

CADMIUM zinc telluride (CdZnTe) and cadmium manganese telluride (CdMnTe) are prime materials for detecting X-rays and gamma-rays at room temperature due to their high average atomic numbers that are essential to having high stopping-power for incident high-energy electromagnetic radiations. A major obstacle in developing CdZnTe and CdMnTe detectors lies in growing crystals free from defects, such as Te inclusions, dislocations, sub-grain boundary networks, and precipitates. We present the results of our study of the relationship between carbon coating of the growth ampoule and dislocations in CdZnTe and sub-grain boundary networks in CdMnTe, grown by Bridgman method. For the CdZnTe crystals, a carbon-coating of 2~\mu\m on the ampoule generated fewer dislocations than did a thinner 0.2 - \mu\m carbon-coated one. Furthermore, the ampoule’s design (normal- or tapered-shape) did not affect the densities of etch pits as much as did the thickness of the carbon-coating. For a CdMnTe ingot with a carbon coating of about 2~\mu\m, created by cracking spectroscopic-grade acetone at \sim 900^\circ C, we observed very few grain boundaries and grain-boundary networks. [ABSTRACT FROM AUTHOR]

In this study, effective atomic numbers of composite materials, polyethylene and coal have been estimated by using Compton scattering of 662keV gamma rays emitted from 137Cs source. In order to estimate the effective atomic numbers, the Klein-Nishina theoretical cross sections were obtained from 500 to 1000 angles. Then, the scattering cross sections of the samples were experimentally determined. By using this method, effective atomic numbers of polyethylene and coal are obtained as 2.25 and 2.39 respectively. [ABSTRACT FROM AUTHOR]

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